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What are the two main veins in the neck, returning blood from the brain to the heart?

Cardiovascular System of the Head and Neck Home > Cardiovascular System > Cardiovascular System of the Head and Neck Cardiovascular System of the Head and Neck The cardiovascular system of the head and neck includes the vital arteries that provide oxygenated blood to the brain and organs of the head, including the mouth and eyes. It also includes the veins that return deoxygenated blood from these organs to the heart. Among these blood vessels are several unique and important structures that have evolved to help maintain the continuous flow of blood to the brain. The human brain is so powerful and metabolically active that it uses about 20% of all of the oxygen and glucose taken in by the body each day.... Move up/down/left/right: Click compass arrows Rotate image: Click and drag in any direction, anywhere in the frame Identify objects: Click on them in the image 2D Interactive 3D Rotate & Zoom Change Anatomical System Change View Angle Full Cardiovascular System of the Head and Neck Description [Continued from above] . . . Any interruption in the blood flow to the brain very quickly results in the decline of mental function, loss of consciousness, and eventually death if not corrected. Oxygenated blood enters the neck from the trunk through four major arteries: the left and right vertebral arteries and the left and right common carotid arteries. The vertebral arteries travel through the transverse foramina of the cervical vertebrae before entering the skull at the foramen magnum and joining at the base of the brain to form the basilar artery. From there the basilar artery provides blood to the posterior structures of the brain, including the brain stem, cerebellum, and cerebrum. The left and right carotid arteries each divide in the neck to form the left and right internal carotid as well as the left and right external carotid arteries. The internal carotid arteries pass into the skull inferior to the brain through the left and right carotid foramina. At the base of the brain, the internal carotid arteries branch off into the left and right anterior cerebral arteries and the left and right middle cerebral arteries that supply blood to the middle and anterior regions of the brain. At the base of the brain several communicating arteries form anastomoses, or passages, between the left and right posterior cerebral, left and right internal carotid, and left and right anterior cerebral arteries. These arteries collectively form a ring of blood vessels known as the Circle of Willis. The Circle of Willis provides insurance that the brain will continue to receive blood flow in the event that one of its major arteries is blocked by allowing blood flow between all of the major arteries to all of the regions of the brain. In the neck and head exterior to the skull, the external carotid artery provides blood flow to the skin, muscles, and organs. Several major arteries - including the facial, superficial temporal, and occipital arteries - branch off from the external carotid to provide blood to the many superficial structures of the head. Three pairs of major veins return deoxygenated blood from the tissues of the head and neck to the heart. The left and right vertebral veins descend through the transverse foramina of the cervical vertebrae to drain blood from the spinal cord, cervical vertebrae, and muscles of the neck. In the head, superficial structures on the exterior of the skull are drained by the pair of external jugular veins, which descend through the neck lateral to the vertebral veins. Most importantly, the brain is drained by a group of large cavities in the dura mater layer of the meninges known as dural venous sinuses. Blood collected in these sinuses drains into the largest veins in the head and neck - the left and right internal jugular veins. The internal jugular veins collect blood from the brain as well as the superficial structures of the head and neck before descending through the neck towards the heart. Prepared by Tim Taylor, Anatomy and Physiology Instructor  

Jugular vein

What is the term fro a series of uncontrollable intakes of air caused by sudden spasms of the diaphragm?

Blood Vessel Distribution Blood Vessel Distribution     Pulmonary Circuit         The pulmonary circuit begins at the semilunar valve of the pulmonary trunk that carries deoxygenated blood to the lungs. The pulmonary trunk divides into left and right pulmonary arteries that go to each lung. Blood is oxygenated in capillaries that flow through the alveoli of the lungs. Oxygenated blood is then returned to the left atrium of the heart by four pulmonary veins.  Systemic Circuit        The systemic circuit begins at the aortic semilunar valve with the ascending aorta. As previously noted, the coronary arteries come off at base of the ascending aorta. The curving aortic arch connects the ascending aorta with the descending aorta.        Three elastic arteries come of aortic arch:   1. brachiocephalic trunk (a.k.a. innominate artery) divides into the right common carotid and right subclavian arteries.   2. left common carotid a.       These arteries supply blood to the head, neck, shoulders and arms.          The subclavian a. give off three major arteries before leaving the thoracic cavity:        1. Thyrocervical trunk        2. Internal thoracic a.        3. Vertebral a.      After leaving the thoracic cavity and passing over the first rib, the subclavian a. becomes the axillary (axillary = armpit) a. After giving off branches that supply the shoulder and chest, the axillary a. enters the arm and becomes the brachial a. In the region of the elbow, the brachial a. divides into the arteries that supply the forearm, the radial a. that follows the radius, and the ulnar a. that follows the ulna. Both the radial and ulnar aa. extend to the wrist.  Systemic Veins      The systemic veins return deoxygenated blood to the right atrium of the heart via the superior vena cava and inferior vena cava.      Many systemic veins run alongside systemic arteries and have the same name as the accompanying artery. In the neck and limbs, in addition to the deep veins that run alongside deep arteries there are superficial veins that are much more variable.      The superior vena cava receives blood from the head, neck, shoulder, chest and arms.  Venous return from upper limb      The superficial veins of the upper limb include the cephalic v. that ascends along radial side of forearm and stays on the lateral side of the arm until it fuses with the axillary v. The basilic v. ascends along the ulnar side of the forearm and stays on the medial side of the arm until it fuses with the brachial v  and continues as the axillary v. The median cubital v. interconnects cephalic and basilic veins.      The deep veins are alongside the arteries and have the same names. The radial and ulnar veins fuse to form brachial v. The brachial v. receives blood from basilic v and becomes axillary v. and the axillary v. receives blood from the cephalic v. and becomes the subclavian v.   Carotid Arteries and the Blood Supply to the Brain          The common carotid a. ascends the neck and divides at the larynx into internal carotid a. and external carotid a. The external carotid a. supplies blood to the neck, pharynx, esophagus, larynx, lower jaw and face. The internal carotid a. enters the cranium through the carotid canal and divides into the:     3. Middle cerebral a.         Blood is also supplied to the brain by the vertebral a. The vertebral a. comes off the subclavian a., ascends through the transverse foramina of the cervical vertebrae and enters cranium through foramen magnum. On the medulla oblongata it fuses to form the basilar a. At the pons the basilar a. divides into the posterior cerebral arteries.        Although the internal carotid a. supplies the anterior brain and the vertebral a. supplies the posterior brain, blood supply to the entire brain is ensured by anastomoses between the vessels from these two sources. This complex of anastomosing arteries is called the cerebral arterial circle (circle of Willis) and includes:   Anterior cerebral arteries linked by anterior communicating artery   Posterior cerebral arteries linked to internal carotids by the posterior communicating arteries  Veins returning blood from cranium      The superficial veins drain blood from cerebrum into dural sinuses. These dural sinuses form within the dura mater of the brain. The location of some of these sinuses can be easily seen by the impressions they leave on the inner surface of the skull. These include the superior sagittal sinus, transverse sinus and sigmoid sinus.      The deep veins that drain blood from the brain, also ultimately drain into the dural sinuses. The blood collected from the brain drains into the sigmoid sinus which exits the cranium by the jugular foramen to become the internal jugular vein.      The vertebral v. collects blood from the cervical spinal cord and rear of the skull. It travels alongside the vertebral a. through transverse foramina of cervical vertebrae.  Superficial veins of head and neck        The facial, temporal and maxillary veins drain blood from the superficial tissues of the head. The temporal and maxillary veins drain into the external jugular v. and the facial vein drains into the internal jugular v. There is a broad anastomosis between the internal and external jugular veins at the angle of the mandible.      The external jugular vein drains into the subclavian v. and the internal jugular v. joins the subclavian v. to form the brachiocephalic v.  Veins within thorax      In the thorax, the external and internal jugular veins fuse with the subclavian v. and become the brachiocephalic v. The right and left brachiocephalic veins fuse to form the superior vena cava.      The azygos v. ascends from lumbar region on right side of vertebral column and drains into the superior vena cava at the level of the second thoracic vertebra. The  smaller hemiazygos v. collects blood from the left side of the thorax and drains into the azygos v. The azygos v. and hemiazygos v are the chief collecting vessels of the thorax.      The inferior vena cava collects blood from organs inferior to diaphragm.  Abdominal Aorta        The descending aorta is divided into thoracic aorta and abdominal aorta by diaphragm. The thoracic aorta supplies blood to viscera of the thoracic cavity and the chest wall.   The abdominal aorta gives off three unpaired arteries:   1. The celiac trunk divides into:    a. Left gastric a. that supplies stomach and esophagus.   b. Splenic a. that supplies spleen, stomach and pancreas.   c. Common hepatic a. that supplies liver, stomach, gall bladder, duodenum and pancreas.   2. Superior mesenteric a. that supplies pancreas, duodenum, small intestines and most of large intestines.   3. Inferior mesenteric a. that supplies the terminal portions of colon and the rectum.   Paired arteries come off the abdominal aorta and include:   Suprarenal a. that supply the adrenal glands.   Renal a. that supply adrenal glands and kidneys.   Gonadal a. that supply ovaries and testes.        The abdominal aorta ends at the level of the fourth lumbar vertebra (L4) where it divides into right and left common iliac arteries. This region is called the terminal segment of the aorta.  Veins draining abdomen       The inferior vena cava drains blood from the lumbar wall, liver, kidneys,  adrenal gland and the diaphragm. The following veins are involved:   1. Lumbar veins drain blood from the lumbar portion of the abdomen.   2. Gonadal veins drain blood from the testicles or ovaries. The left gonadal usually drains into the left renal vein.    3. Hepatic veins drain blood from the liver.   4. Renal veins drain blood from the kidneys.    5. Suprarenal veins drain blood from the adrenal glands.    6. Phrenic veins drain blood from the diaphragm.   Hepatic Portal System       Of the digestive organs, only blood draining from the liver goes directly to the inferior vena cava. Blood from the small intestines, large intestines, stomach, pancreas and spleen flows into the liver by the hepatic portal vein.      The veins that drain into the hepatic portal vein include the superior mesenteric v., inferior mesenteric v. and splenic v. This blood is nutrient-rich but oxygen-poor. Oxygen-rich blood is delivered to the liver by the hepatic artery proper. This arrangement allows the liver to perform its processing and storage functions.      The blood from the hepatic portal vein flows through sinusoids in the liver and is collected by the hepatic veins.  Arteries of Pelvis and Lower Limbs        The common iliac a. supplies pelvis and lower limb. At the level of the lumbosacral joint it divides into:        1. Internal iliac a. that supplies urinary bladder, pelvis, external genitalia and medial side of thigh.        2. External iliac a. that supplies lower limb. The external iliac a. penetrates abdominal wall and becomes the femoral a. The deep femoral a. that supplies the muscles of the thigh branches off the femoral a. The femoral a. continues on the back side of the femur and becomes the popliteal a. after it pierces through the adductor magnus and crosses the popliteal fossa. The popliteal a. divides into the anterior tibial a. and the posterior tibial a. Veins draining lower limbs        The deep veins of the lower limbs are again alongside the arteries of the same name. The anterior tibial v. and posterior tibial v. drain blood from lower leg and fuse to form the popliteal v. The ascends alongside the femur and becomes the femoral v. The deep femoral v. that collects blood from the inner thigh drains into the femoral v. When the femoral v. penetrates the abdominal wall it is called the internal iliac v.      The superficial veins of the lower limb include the great saphenous v. that ascend along the medial aspect of the leg and thigh and drains into the femoral v. and the small saphenous v. that ascends along the posterior and lateral side of the leg and joins the popliteal v.   Veins draining pelvis      Inside the pelvis external iliac v. merges with internal iliac v. to form common iliac v.  The common iliac veins fuse at the 5th lumbar vertebra to form the inferior vena cava.   Fetal Circulation         Differences between the adult and fetal circulation reflect differences in the nutritional and respiratory support. The fetus depends upon the maternal circulation for oxygen, nutrients and waste removal. Exchange takes place at the placenta. In the fetus, two umbilical arteries branch off internal iliac arteries and go to the placenta and a single umbilical vein drains the placenta.      The umbilical vein drains oxygenated and nutrient-rich blood into ductus venosus in liver. The ductus venosus also receives deoxygenated blood from the liver and drains into the inferior vena cava.      The fetal pulmonary circuit is not as important to the fetus as the lung is collapsed. Some of the blood that enters the right atrium bypasses the pulmonary circuit by going through an opening in the interatrial septum called the foramen ovale. As blood leaves the right ventricle another major portion of blood bypasses the pulmonary circuit by going through a short muscular artery that connects the pulmonary trunk with the aorta called the ductus arteriosus.      At birth, the lungs open and receive air and the pulmonary circuit becomes important. The ductus arteriosus undergoes vasoconstriction that is strong enough to stop the flow of blood. The ductus arteriosus then undergoes fibrosis to become the ligamentum arteriosum. As blood pressure rises in the left atrium a one way valve closes the foramen ovale and it adheres to the wall and undergoes fibrosis. It leaves a remnant in the interatrial septum called the fossa ovalis.      At birth, the neonate also begins to rely on its own digestive system. The ductus venosus vasoconstricts and undergoes fibrosis to become the ligamentum venosum. Blood ceases to flow to the placenta by the umbilical arteries that collapse and become the median umbilical ligaments. The umbilical vein also collapses and becomes the round ligament or ligamentum teres.      The following summarizes the changes:  

i don't know

Which part of the eye contains about 137 million light-sensitive cells in one square inch?

Eye | Creation Facts Creation Facts Evidence From Anatomy September 13th, 2009 The eye is an incredibly complex organ that moves 100,000 times in an average day. Numerous muscles and tear ducts are in place to keep the eye constantly moist, protected, and functional. Our eyes process 1.5 million bits of information simultaneously and provide 80% of the sensory stimulation sent to the brain. They receive light images traveling at 186,000 miles per second through the iris, which opens or closes to let in just the right amount of light. These images travel through a lens, made of transparent cells, which focuses them on the retina at the back of the eyeball. The retina covers less than one square inch of surface, yet this square inch contains approximately 137 million light-sensitive receptor  cells. Approximately 130 million are rod cells (designed specifically to see in black and white), and 7 million are cone cells (allowing color vision). Finally, the image is sent at a rate of 300 miles per hour to the brain for processing. How could all of this have come about by some step-by-step, random-chance evolutionary process? Mankind has designed and patterned the camera after the eye. It is only reasonable to acknowledge that the eye, which is an infinitely more complex instrument, was also designed by intelligence.

Retina

What is the more common name for the tympanic membrane?

photoreception | biology | Britannica.com Photoreception visual pigment Photoreception, any of the biological responses of animals to stimulation by light . The mammalian eye has a cornea and a lens and functions as a dioptric system, in which light rays … Encyclopædia Britannica, Inc. In animals photoreception refers to mechanisms of light detection that lead to vision and depends on specialized light-sensitive cells called photoreceptors, which are located in the eye . The quality of vision provided by photoreceptors varies enormously among animals. For example, some simple eyes such as those of flatworms have few photoreceptors and are capable of determining only the approximate direction of a light source. In contrast, the human eye has 100 million photoreceptors and can resolve one minute of arc (one-sixtieth of a degree), which is about 4,000 times better than the resolution achieved by the flatworm eye. The following article discusses the diversity and evolution of eyes, the structure and function of photoreceptors, and the central processing of visual information in the brain . For more information about the detection of light, see optics ; for general aspects concerning the response of organisms to their environments, see sensory reception . Diversity of eyes The eyes of animals are diverse not only in size and shape but also in the ways in which they function. For example, the eyes of fish from the deep sea often show variations on the basic spherical design of the eye. In these fish, the eye’s field of view is restricted to the upward direction, presumably because this is the only direction from which there is any light from the surface. This makes the eye tubular in shape. Some fish living in the deep sea have reduced eyelike structures directed downward (e.g., Bathylychnops, which has a second lens and retina attached to the main eye); it is thought that the function of these structures is to detect bioluminescent creatures. On the ocean floor, where no light from the sky penetrates, eyes are often reduced or absent. However, in the case of Ipnops, which appears to be eyeless, the retina is still present as a pair of plates covering the front of the top of the head, although there is no lens or any other optical structure. The function of this eye is unknown. The optical arrangements of eyes differ among nocturnal, arhythmic, and diurnal animals. Encyclopædia Britannica, Inc. chemoreception The placing of the eyes in the head varies. Predators, such as felines and owls , have forward-pointing eyes and the ability to judge distance by binocular triangulation. Herbivorous species that are likely to be victims of predation, such as mice and rabbits , usually have their eyes almost opposite each other, giving near-complete coverage of their surroundings. In addition to placement in the head, the structure of the eye varies among animals. Nocturnal animals, such as the house mouse and opossum , have almost spherical lenses filling most of the eye cavity. This design allows the eye to capture the maximum amount of light possible. In contrast, diurnal animals, such as humans and most birds , have smaller, thinner lenses placed well forward in the eye. Nocturnal animals usually have retinas with a preponderance of photoreceptors called rods , which do not detect colour but perceive size, shape, and brightness. Strictly diurnal animals, such as squirrels and many birds, have retinas containing photoreceptors called cones , which perceive both colour and fine detail. A slit pupil is common in nocturnal animals, as it can be closed more effectively in bright light than a round pupil. In addition, nocturnal animals, such as cats and bush babies , are usually equipped with a tapetum lucidum , a reflector behind the retina designed to give receptors a second chance to catch photons that were missed on their first passage through the retina. The almost spherical lenses in opossum eyes ensure high light-gathering ability at night. Encyclopædia Britannica, Inc. Nocturnal animals such as opossums have eyes with large, nearly spherical lenses. W. Perry Conway/Corbis Ringling Bros. Folds Its Tent Animals such as seals , otters , and diving birds, which move from air to water and back, have evolved uniquely shaped corneas —the transparent membrane in front of the eye that separates fluids inside the eye from fluids outside the eye. The cornea functions to increase the focusing power of the eye; however, optical power is greatly reduced when there is fluid on both sides of the membrane. As a result, seals, which have a nearly flat cornea with little optical power in air or water, rely on a re-evolved spherical lens to produce images. Diving ducks , on the other hand, compensate for the loss of optical power in water by squeezing the lens into the bony ring around the iris, forming a high curvature blip on the lens surface, which shortens its focal length (the distance from the retina to the centre of the lens). One of the most interesting examples of amphibious optics occurs in the “four-eyed fish” of the genus Anableps , which cruises the surface meniscus with the upper part of the eye looking into air and the lower part looking into water. It makes use of an elliptical lens, with the relatively flat sides adding little to the power of the cornea and the higher curvature ends focusing light from below the surface, where the cornea is ineffective. Though the eyes of animals are diverse in structure and use distinct optical mechanisms to achieve resolution, eyes can be differentiated into two primary types: single-chambered and compound . Single-chambered eyes (sometimes called camera eyes) are concave structures in which the photoreceptors are supplied with light that enters the eye through a single lens. In contrast, compound eyes are convex structures in which the photoreceptors are supplied with light that enters the eye through multiple lenses. The possession of multiple lenses is what gives these eyes their characteristic faceted appearance. Single-chambered eyes Science Quiz Pigment cup eyes In most of the invertebrate phyla, eyes consist of a cup of dark pigment that contains anywhere from a few photoreceptors to a few hundred photoreceptors. In most pigment cup eyes there is no optical system other than the opening, or aperture , through which light enters the cup. This aperture acts as a wide pinhole and restricts the width of the cone of light that reaches any one photoreceptor, thereby providing a very limited degree of resolution. Pigment cup eyes are very small, typically 100 μm (0.004 inch) or less in diameter. They are capable of supplying information about the general direction of light, which is adequate for finding the right part of the environment in which to seek food. However, they are of little value for hunting prey or evading predators. In 1977 Austrian zoologist Luitfried von Salvini-Plawen and American biologist Ernst Mayr estimated that pigment cup eyes evolved independently between 40 and 65 times across the animal kingdom. These estimates were based on a variety of differences in microstructure among pigment cup eyes of different organisms. Pigment cup eyes were undoubtedly the starting point for the evolution of the much larger and more optically complex eyes of mollusks and vertebrates . Pinhole eyes Facebook Twitter YouTube Instagram Pinterest Pinhole eyes, in which the size of the pigment aperture is reduced, have better resolution than pigment cup eyes. The most impressive pinhole eyes are found in the mollusk genus Nautilus , a member of a cephalopod group that has changed little since the Cambrian Period (about 542 million to 488 million years ago). These organisms have eyes that are large, about 10 mm (0.39 inch) across, with millions of photoreceptors. They also have muscles that move the eyes and pupils that can vary in diameter, from 0.4–2.8 mm (0.02–0.11 inch), with light intensity. These features all suggest an eye that should be comparable in performance to the eyes of other cephalopods, such as the genus Octopus . However, because there is no lens and each photoreceptor must cover a wide angle of the field of view, the image in the Nautilus eye is of very poor resolution. Even with the pupil at its smallest, each receptor views an angle of more than two degrees, compared with a few fractions of a degree in Octopus. In addition, because the pupil has to be small in order to achieve even a modest degree of resolution, the image produced in the Nautilus eye is extremely dim. Thus, a limitation of pinhole eyes is that any improvement in resolution is at the expense of sensitivity; this is not true of eyes that contain lenses. There are one or two other eyes in gastropod mollusks that could qualify as pinhole eyes, notably those of the abalone genus Haliotis. However, none of these eyes rival the eyes of Nautilus in size or complexity. The chambered nautilus (Nautilus) has eyes that are large, about 10 mm (0.39 inch) … Douglas Faulkner Editor Picks: Exploring 10 Types of Basketball Movies Relative to pinhole eyes, lens eyes have greatly improved resolution and image brightness . Lenses were formed by increasing the refractive index of material in the chamber by adding denser material, such as mucus or protein. This converged incoming rays of light, thereby reducing the angle over which each photoreceptor receives light. The continuation of this process ultimately results in a lens capable of forming an image focused on the retina. Most lenses in aquatic animals are spherical, because this shape gives the shortest focal length for a lens of a given diameter, which in turn gives the brightest image. Lens eyes focus an image either by physically moving the lens toward or away from the retina or by using eye muscles to adjust the shape of the lens. True octopuses (genus Octopus) have lens eyes that contain photoreceptors capable … Beckmannjan For many years the lens properties that allow for the formation of quality images in the eye were poorly understood. Lenses made of homogeneous material (e.g., glass or dry protein) suffer from a defect known as spherical aberration , in which peripheral rays are focused too strongly, resulting in a poor image. In the 19th century, Scottish mathematician and physicist James Clerk Maxwell discovered that the lens of the eye must contain a gradient of refractive index , with the highest degree of refraction occurring in the centre of the lens. In the late 19th century the physiologist Matthiessen showed that this was true for fish, marine mammals , and cephalopod mollusks. It is also true of many gastropod mollusks, some marine worms (family Alciopidae), and at least one group of crustaceans , the copepod genus Labidocera. Two measurements, focal length and radius of curvature of the lens, can be used to distinguish gradient lenses from homogeneous lenses. For example, gradient lenses have a much shorter focal length than homogeneous lenses with the same central refractive index , and the radius of curvature of a gradient lens is about 2.5 lens radii, compared with 4 radii for a homogeneous lens. The ratio of focal length to radius of curvature is known as the Matthiessen ratio (named for its discoverer, German physicist and zoologist Ludwig Matthiessen) and is used to determine the optical quality of lenses. Trending Topics Opium Wars The lens eyes of fish and cephalopod mollusks are superficially very similar. Both are spherical and have a Matthiessen ratio lens that can be focused by moving it toward and away from the retina, an iris that can contract, and external muscles that move the eyes in similar ways. However, fish and cephalopod mollusks evolved quite independently of each other. An obvious difference between the eyes of these organisms is in the structure of the retina. The vertebrate retina is inverse, with the neurons emerging from the front of the retina and the nerve fibres burrowing out through the optic disk at the back of the eye to form the optic nerve . The cephalopod retina is everse, meaning the fibres of the neurons leave the eye directly from the rear portions of the photoreceptors. The photoreceptors themselves are different too. Vertebrate photoreceptors, the rods and cones , are made of disks derived from cilia , and they hyperpolarize (become more negative) when light strikes them. In contrast, cephalopod photoreceptors are made from arrays of microvilli (fingerlike projections) and depolarize (become less negative) in response to light. The developmental origins of the eyes are also different. Vertebrate eyes come from neural tissue, whereas cephalopod eyes come from epidermal tissue. This is a classic case of convergent evolution and demonstrates the development of functional similarities derived from common constraints. Corneal eyes When vertebrates emerged onto land, they acquired a new refracting surface, the cornea. Because of the difference in refractive index between air and water, a curved cornea is an image-forming lens in its own right. Its focal length is given by f = nr/(n-1), where n is the refractive index of the fluid of the eye, and r is the radius of curvature of the cornea. All land vertebrates have lenses, but the lens is flattened and weakened compared with a fish lens. In the human eye the cornea is responsible for about two-thirds of the eye’s optical power, and the lens provides the remaining one-third. Spherical corneas, similar to spherical lenses, can suffer from spherical aberration . To avoid this, the human cornea developed an ellipsoidal shape, with the highest curvature in the centre. A consequence of this nonspherical design is that the cornea has only one axis of symmetry, and the best image quality occurs close to this axis, which corresponds with central vision (as opposed to peripheral vision). In addition, central vision is aided by a region of high photoreceptor density, known as the fovea or the less clearly defined “area centralis,” that lies close to the central axis of the eye and specializes in acute vision. Corneal eyes are found in spiders , many of which have eyes with excellent image-forming capabilities. Spiders typically have eight eyes, two of which, the principal eyes, point forward and are used in tasks such as the recognition of members of their own species. Hunting spiders use the remaining three pairs, secondary eyes, as movement detectors. However, in web-building spiders, the secondary eyes are underfocused and are used as navigation aids, detecting the position of the Sun and the pattern of polarized light in the sky. Jumping spiders have the best vision of any spider group, and their principal eyes can resolve a few minutes of arc, which is many times better than the eyes of the insects on which they prey. The eyes of jumping spiders are also unusual in that the retinas scan to and fro across the image while the spider identifies the nature of its target. Jumping spiders, so named because they stalk and leap upon their prey, have keener vision than most … Steve Taylor—Stone/Getty Images Insects also have corneal single-chambered eyes. The main eyes of many insect larvae consist of a small number of ocelli, each with a single cornea. The main organs of sight of most insects as adults are the compound eyes, but flying insects also have three simple dorsal ocelli. These are generally underfocused, giving blurred images; their function is to monitor the zenith and the horizon, supplying a rapid reaction system for maintaining level flight. Concave mirror eyes Scallops ( Pecten) have about 50–100 single-chambered eyes in which the image is formed not by a lens but by a concave mirror. In 1965 British neurobiologist Michael F. Land (the author of this article) found that although scallop eyes have a lens, it is too weak to produce an image in the eye. In order to form a visible image, the back of the eye contains a mirror that reflects light to the photoreceptors. The mirror in Pecten is a multilayer structure made of alternating layers of guanine and cytoplasm , and each layer is a quarter of a wavelength (about 0.1 μm in the visible spectrum ) thick. The structure produces constructive interference for green light, which gives it its high reflectance. Many other mirrors in animals are constructed in a similar manner, including the scales of silvery fish, the wings of certain butterflies (e.g., the Morpho genus), and the iridescent feathers of many birds. The eyes of Pecten also have two retinas, one made up of a layer of conventional microvillus receptors close to the mirror and out of focus, and the second made up of a layer with ciliary receptors in the plane of the image. The second layer responds when the image of a dark object moves across it; this response causes the scallop to shut its shell in defense against potential predation. Reflecting eyes such as those of Pecten are not common. A number of copepod and ostracod crustaceans possess eyes with mirrors, but the mirrors are so small that it is difficult to tell whether the images are used. An exception is the large ostracod Gigantocypris, a creature with two parabolic reflectors several millimetres across. It lives in the deep ocean and probably uses its eyes to detect bioluminescent organisms on which it preys. The images are poor, but the light-gathering power is enormous. A problem with all concave mirror eyes is that light passes through the retina once, unfocused, before it returns, focused, from the mirror. As a result, photoreceptors see a low-contrast image, and this design flaw probably accounts for the rare occurrence of these eyes. Compound eyes Compound eyes are made up of many optical elements arranged around the outside of a convex supporting structure. They fall into two broad categories with fundamentally different optical mechanisms. In apposition compound eyes each lens with its associated photoreceptors is an independent unit (the ommatidium ), which views the light from a small region of the outside world. In superposition eyes the optical elements do not act independently; instead, they act together to produce a single erect image lying deep in the eye. In this respect they have more in common with single-chambered eyes, even though the way the image is produced is quite different. Apposition eyes Apposition eyes were almost certainly the original type of compound eye and are the oldest fossil eyes known, identified from the trilobites of the Cambrian Period . Although compound eyes are most often associated with the arthropods , especially insects and crustaceans , compound eyes evolved independently in two other phyla, the mollusks and the annelids . In the mollusk phylum, clams of the genera Arca and Barbatia have numerous tiny compound eyes, each with up to a hundred ommatidia, situated around their mantles . In these tiny eyes each ommatidium consists of a photoreceptor cell and screening pigment cells. The eyes have no lenses and rely simply on shadowing from the pigment tube to restrict the field of view. In the annelid phylum the tube worms of the family Sabellidae have eyes similar to those of Arca and Barbatia at various locations on the tentacles. However, these eyes differ in that they have lenses. The function of the eyes of both mollusks and annelids is much the same as the mirror eyes of Pecten; they see movement and initiate protective behaviour, causing the shell to shut or the organism to withdraw into a tube. Apposition eyes have short ommatidia, each of which focuses on only a small area of the field of … Encyclopædia Britannica, Inc. Image formation In arthropods most apposition eyes have a similar structure. Each ommatidium consists of a cornea , which in land insects is curved and acts as a lens. Beneath the cornea is a transparent crystalline cone through which rays converge to an image at the tip of a receptive structure, known as the rhabdom . The rhabdom is rodlike and consists of interdigitating fingerlike processes ( microvilli ) contributed by a small number of photoreceptor cells. The number of microvilli varies, with eight being the typical number found in insects . In addition, there are pigment cells of various kinds that separate one ommatidium from the next; these cells may act to restrict the amount of light that each rhabdom receives. Beneath the photoreceptor cells there are usually three ganglionic layers—the lamina, the medulla, and the lobula—that form a set of neuronal relays, and the rhabdom is connected to these layers by a single axon . The neuronal relays map and remap input from the retinal photoreceptors, thereby generating increasingly complex responses to contrast, motion, and form. In aquatic insects and crustaceans the corneal surface cannot act as a lens because it has no refractive power. Some water bugs (e.g., Notonecta, or back swimmers ) use curved surfaces behind and within the lens to achieve the required ray bending, whereas others use a structure known as a lens cylinder. Similar to fish lenses, lens cylinders bend light, using an internal gradient of refractive index , highest on the axis and falling parabolically to the cylinder wall. In the 1890s Austrian physiologist Sigmund Exner was the first to show that lens cylinders can be used to form images in the eye. He discovered this during his studies of the ommatidia of the horseshoe crab Limulus . A problem that remained poorly understood until the 1960s is the relationship between the inverted images formed in individual ommatidia and the image formed across the eye as a whole. The question was first raised in the 1690s when Dutch scientist Antonie van Leeuwenhoek observed multiple inverted images of his candle flame through the cleaned cornea of an insect eye. Later investigations of the ommatidial structure revealed that in apposition eyes each ommatidium is independent and sees a small portion of the field of view. The field of view is defined by the lens, which also serves to increase the amount of light reaching the rhabdom. Each rhabdom scrambles and averages the light it receives, and the individual ommatidial images are sent via neurons from the ommatidia to the brain . In the brain, the separate images are perceived as a single overall image. The array of images formed by the convex sampling surface of the apposition compound eye is functionally equivalent to the concave sampling surface of the retina in a single-chambered eye. Neural superposition eyes Conventional apposition eyes, such as those of bees and crabs , have a similar optical design to the eyes of flies ( Diptera ). However, in fly eyes the photopigment-bearing membrane regions of the photoreceptors are not fused into a single rhabdom. Instead, they stay separated as eight individual rodlets (effectively seven, since two lie one above the other), known as rhabdomeres, each with its own axon . This means that each ommatidium should be capable of a seven-point resolution of the image, which raises the problem of incorporating multiple inverted images into a single erect image that the ordinary apposition eye avoids. In 1967 German biologist Kuno Kirschfeld showed that the angles between the individual rhabdomeres in one ommatidium are the same as those between adjacent ommatidia. As a result, each of the seven rhabdomeres in one ommatidium shares a field of view with a rhabdomere in a neighbouring ommatidium. In addition, all seven rhabdomeres that share a common field of view send their axons to the same place in the first ganglionic layer—the lamina. Thus, at the level of the lamina the image is no different from that in an ordinary apposition eye. However, because each of the seven photoreceptor axon inputs connects to second-order neurons , the image at the level of the lamina is effectively seven times brighter than in the photoreceptors themselves. This allows flies to fly earlier in the morning and later in the evening than other insects with eyes of similar resolution. This variant of the apposition eye has been called neural superposition. Wavelength and plane of polarization Although there is no further spatial resolution within a rhabdom , the various photoreceptors in each ommatidium do have the capacity to resolve two other features of the image, wavelength and plane of polarization . The different photoreceptors do not all have the same spectral sensitivities (sensitivities to different wavelengths). For example, in the honeybee there are three photopigments in each ommatidium, with maximum sensitivities in the ultraviolet, the blue, and the green regions of the spectrum. This forms the basis of a trichromatic colour vision system that allows bees to distinguish accurately between different flower colours. Some butterflies have four visual pigments , one of which is maximally sensitive to red wavelengths. The most impressive array of pigments is found in mantis shrimps (order Stomatopoda), where there are 12 visual pigments in a special band across the eye. Eight pigments cover the visible spectrum, and four cover the ultraviolet region. Unlike humans, many arthropods have the ability to resolve the plane of polarized light. Single photons of light are wave packets in which the electrical and magnetic components of the wave are at right angles. The plane that contains the electrical component is known as the plane of polarization. Sunlight contains photons polarized in all possible planes and therefore is unpolarized. However, the atmosphere scatters light selectively, in a way that results in a pattern of polarization in the sky that is directly related to the position of the Sun. Austrian zoologist Karl von Frisch showed that bees could navigate by using the pattern of polarization instead of the Sun when the sky was overcast. The organization of the photopigment molecules on the microvilli in the rhabdoms of bees makes this type of navigation possible. A photon will be detected only if the light-sensitive double bond of the photopigment molecule lies in the plane of polarization of the photon. The rhabdoms in the dorsal regions of bee eyes have their photopigment molecules aligned with the axes of the microvilli , which lie parallel to one another in the photoreceptor. As a result, each photoreceptor is able to act as a detector for a particular plane of polarization. The whole array of detectors in the bee’s eyes is arranged in a way that matches the polarization pattern in the sky, thus enabling the bee to easily detect the symmetry plane of the pattern, which is the plane containing the Sun. The other physical process that results in polarization is reflection . For example, a water surface polarizes reflected light so that the plane of polarization is parallel to the plane of the surface. Many insects, including back swimmers of Notonecta, make use of this property to find water when flying between pools. The mechanism is essentially the same as in the bee eye. There are pairs of photoreceptors with opposing microvillar orientations in the downward-pointing region of the eye, and when the photoreceptors are differentially stimulated by the polarized light from a reflecting surface, the insect makes a dive. The reason that humans cannot detect polarized light is that the photopigment molecules can take up all possible orientations within the disks of the rods and cones , unlike the microvilli of arthropods, in which the molecules are constrained to lie parallel to the microvillar axis. Back swimmers (genus Notonecta) have eyes capable of detecting the plane of … Jane Burton/Bruce Coleman Ltd. Differences in resolution The number of ommatidia in apposition eyes varies from a handful, as in primitive wingless insects and some ants , to as many as 30,000 in each eye of some dragonflies (order Odonata ). The housefly has 3,000 ommatidia per eye, and the vinegar fly (or fruit fly) has 700 per eye. In general, the resolution of the eye increases with increasing ommatidial number. However, the physical principle of diffraction means that the smaller the lens, the worse the resolution of the image. This is why astronomical telescopes have huge lenses (or mirrors), and it is also why the tiny lenses of compound eyes have poor resolution. A bee’s eye, with 25-μm- (0.001-inch-) wide lenses, can resolve about one degree. The human eye, with normal visual acuity (20/20 vision), can resolve lines spaced less than one arc minute (one-sixtieth of one degree) apart, which is about 60 times better than a bee. In addition, the single lens of the human eye has an aperture diameter (in daylight) of 2.5 mm (0.1 inch), 100 times wider than that of a single lens of a bee. If a bee were to attempt to improve its resolution by a factor of two, it would have to double the diameter of each lens, and it would need to double the number of ommatidia to exploit the improved resolution. As a result, the size of an apposition eye would increase as the square of the required resolution, leading to absurdly large eyes. In 1894 British physicist Henry Mallock calculated that a compound eye with the same resolution as human central vision would have a radius of 6 metres (19 feet). Given this problem, a resolution of one-quarter of a degree, found in the large eyes of dragonflies, is probably the best that any insect can manage. Because increased resolution comes at a very high cost in terms of overall eye size, many insects have eyes with local regions of increased resolution (acute zones), in which the lenses are larger. The need for higher resolution is usually connected with sex or predation. In many male dipteran flies and male (drone) bees, there is an area in the upper frontal region of the eyes where the facets are enlarged, giving resolution that is up to three times more acute than elsewhere in the eye. The acute resolution is used in the detection and pursuit of females. In one hover fly genus (Syritta) the males make use of their superior resolution to stay just outside the distance at which females can detect them. In this way a male can stalk a female on the wing until she lands on a flower, at which point he pounces. In a few flies, such as male bibionids ( March flies ) and simuliids ( black flies ), the high- and low-resolution parts of the eye form separate structures, making the eye appear doubled. Insects that catch other insects on the wing also have special “acute zones.” Both sexes of robber fly (family Asilidae) have enlarged facets in the frontal region of the eye, and dragonflies have a variety of more or less upward-pointing high-resolution regions that they use to spot flying insects against the sky. The hyperiid amphipods , medium-sized crustaceans from the shallow and deep waters of the ocean, have visual problems similar to those of dragonflies, although in this case they are trying to spot the silhouettes of potential prey against the residual light from the surface. This has led to the development of highly specialized divided eyes in some species, most notably in Phronima, in which the whole of the top of the head is used to provide high resolution and sensitivity over a narrow (about 10 degrees) field of view. Not all acute zones are upward-pointing. Some empid flies (or dance flies ), which cruise around just above ponds looking for insects trapped in the water surface, have enlarged facets arranged in a belt around the eye’s equator—the region that views the water surface. Superposition eyes Crepuscular (active at twilight) and nocturnal insects (e.g., moths ), as well as many crustaceans from the dim midwater regions of the ocean, have compound eyes known as superposition eyes, which are fundamentally different from the apposition type. Superposition eyes look superficially similar to apposition eyes in that they have an array of facets around a convex structure. However, outside of this superficial resemblance, the two types differ greatly. The key anatomical features of superposition eyes include the existence of a wide transparent clear zone beneath the optical elements and a deep-lying retinal layer, usually situated about halfway between the eye surface and the centre of curvature of the eye. Unlike apposition eyes, where the lenses each form a small inverted image, the optical elements in superposition eyes form a single erect image, located deep in the eye on the surface of the retina. The image is formed by the superimposed (hence the name superposition) ray-contributions from a large number of facets. Thus, in some ways this type of eye resembles the single-chambered eye in that there is only one image, which is projected through a transparent region onto the retina. Refracting, reflecting, and parabolic optical mechanisms In superposition eyes the number of facets that contribute to the production of a single image depends on the type of optical mechanism involved. There are three general mechanisms, based on lenses (refracting superposition), mirrors (reflecting superposition), and lens-mirror combinations (parabolic superposition). The refracting superposition mechanism was discovered by Austrian physiologist Sigmund Exner in the 1880s. He reasoned that the geometrical requirement for superposition was that each lens element should bend light in such a way that rays entering the element at a given angle to its axis would emerge at a similar angle on the same side of the axis. Exner realized that this was not the behaviour of a normal lens, which forms an image on the opposite side of the axis from the entering ray. He worked out that the only optical structures capable of producing the required ray paths were two-lens devices, specifically two-lens inverting telescopes. However, the lenslike elements of superposition eyes lack the necessary power in their outer and inner refracting surfaces to operate as telescopes. Exner solved this by postulating that the elements have a lens cylinder structure with a gradient of refractive index capable of bending light rays continuously within the structure. This is similar to the apposition lens cylinder elements in the Limulus eye (see above Apposition eyes ); the difference is that the telescope lenses would be twice as long. The lens cylinder arrangement produces the equivalent of a pair of lenses, with the first lens producing a small image halfway down the structure and the second lens turning the image back into a parallel beam. In the process the ray direction is reversed. Thus, the emerging beam is on the same side of the axis as the entering beam—the condition for obtaining a superposition image from the whole array. In the 1970s, studies using an interference microscope , a device capable of exploring the refractive index distribution in sections of minute objects, showed that Exner’s brilliant idea was accurate in all important details. There is one group of animals with eyes that fit the anatomical criteria for superposition but that have optical elements that are not lenses or lens cylinders. These are the long-bodied decapod crustaceans, such as shrimps , prawns , crayfish , and lobsters . The optical structures are peculiar in that they have a square rather than a circular cross section, and they are made of homogeneous low-refractive index jelly. For a period of 20 years—between 1955, when interference microscopy showed that the jelly structures lacked appropriate refracting properties, and 1975, when the true nature of these structures was discovered—there was much confusion about how these eyes might function. Working with crayfish eyes, German neurobiologist Klaus Vogt found that these unpromising jelly boxes were silvered with a multilayer reflector coating. A set of plane mirrors, aligned at right angles to the eye surface, change the direction of rays (in much the same way as len cylinders), thereby producing a single erect image by superposition. The square arrangement of the mirrors has particular significance. Rays entering the eye at an oblique angle encounter two surfaces of each mirror box rather than one surface. In this case, the pair of mirrors at right angles acts as a corner reflector. Corner reflectors reflect an incoming ray through 180 degrees, irrespective of the ray’s original direction. As a result, the reflectors behave as though they were a single plane mirror at right angles to the ray. This ensures that all parallel rays reach the same focal point and means that the eye as a whole has no single axis, which allows the eye to operate over a wide angle. The third type of superposition eye, discovered in 1988 in the crab genus Macropipus by Swedish zoologist Dan-Eric Nilsson , has optical elements that use a combination of a single lens and a parabolic mirror. The lens focuses an image near the top of the clear zone (similar to an apposition eye), but oblique rays are intercepted by a parabolic mirror surface that lines the crystalline cone beneath the lens. The parabolic mirror unfocuses the light and redirects it back across the axis of the structure, producing an emerging ray path similar to that of a refracting or reflecting superposition eye. All three types of superposition eyes have adaptation mechanisms that restrict the amount of light reaching the retina in bright conditions. In most cases, light is restricted by the migration of dark pigment (held between the crystalline cones in the dark) into the clear zone; this cuts off the most oblique rays. However, as the pigment progresses inward, it cuts off more and more of the image-forming beam until only the central optical element supplies light to the rhabdom (located immediately below the central optical element). This effectively converts the superposition eye into an apposition eye, since in the dark-adapted condition up to a thousand facets may contribute to the image at any one point on the retina, potentially reducing the retinal illumination a thousandfold. Optics of superposition eyes Superposition optics requires that parallel rays from a large portion of the eye surface meet at a single point in the image. As a result, superposition eyes should have a simple spherical geometry, and, in fact, most superposition eyes in both insects and crustaceans are spherical. Some moth eyes do depart slightly from a spherical form, but it is in the euphausiid crustaceans ( krill ) from the mid-waters of the ocean that striking asymmetries are found. In many krill species the eyes are double. One part, with a small field of view, points upward, and a second part, with a wide field of view, points downward (similar to the apposition eyes of hyperiid amphipods). It is likely that the upper part is used to spot potential prey against the residual light from the sky, and the lower part scans the abyss for bioluminescent organisms. The most extraordinary double superposition eyes occur in the tropical mysid shrimp genus Dioptromysis, which has a normal-looking eye that contains a single enormous facet embedded in the back, with an equally large lens cylinder behind the facet. This single optical element supplies a fine-grain retina, which seems to act as the “fovea” of the eye as a whole. At certain times the eyes rotate so that the single facets are directed forward to view the scene ahead with higher resolution, much as one would use a pair of binoculars . Page 1 of 3

i don't know

What is the name for a red blood cell?

What is a Red Blood Cell? (with pictures) What is a Red Blood Cell? Originally Written By: Michael Anissimov Revised By: Jillian O Keeffe Edited By: Bronwyn Harris Last Modified Date: 08 December 2016 Copyright Protected: Top 10 facts about the world A red blood cell, or erythrocyte , is the most common type of cell in blood. It carries oxygen throughout the circulatory system, from the lungs to the rest of the body, and brings carbon dioxide waste back the other way. All of the body's tissues are dependent upon oxygen from these cells — if the flow is cut off, the tissue dies. There are several medical conditions associated with red blood cells specifically, including sickle-cell anemia, thalassemia, and spherocytosis, but changes in the amount of these cells can also be a sign of other disorders. Characteristics Red blood cells have a diameter of about 6 to 8 micrometers (millionths of a meter), which is similar in size to most cells in the body. They are round and red, with a depression in the center. Adult humans have 20 to 30 trillion of these cells in their bodies, with men having more on average than women, and each one lives for about 120 days before being broken down. They are very flexible, which is important for their functioning, since they often have to squeeze through small openings. Ad Function The main purpose of red blood cells is to transport oxygen and carbon dioxide through the circulatory system. The reason they can do this is that they contain an iron-containing protein called hemoglobin, which binds to oxygen. When the oxygen and the hemoglobin combine, they cause the cells to become bright red. This is why blood looks red when it goes outside of the body as well — when exposed to the open through a cut, the cells become exposed to a lot of atmospheric oxygen. Once all the oxygen connected to the cells is used up, then they collect carbon dioxide and other waste gases from the body and bring it back to the lungs, where they swap it for oxygen and start the cycle again. Related Disorders There are a variety of medical disorders associated with red blood cells, with one of the most common being sickle-cell disease. This is a genetic disorder that causes the cells to become stiff and sickle-shaped. This makes them unable to move properly throughout the circulatory system, and can lead to a variety of problems, including strokes, blindness, and chronic pain. Spherocytosis is another genetic condition that changes the shape of cells and makes them brittle, but unlike sickle-cell disease, it makes them spherical. Several other conditions cause red blood cell abnormalities by disrupting the proper production of hemoglobin. This includes thalassemia, a genetic disorder that causes abnormal hemoglobin molecules, and pernicious anemia, in which the body doesn't absorb enough B12, which is needed for making hemoglobin. Additionally, conditions like G6PD deficiency, hemolytic disease of the fetus and newborn, and aplastic anemia can cause problems with the creation and life of red blood cells. Besides conditions that affect the cells themselves, having an increase or decrease in the number of red blood cells in the body can be a symptom of several conditions. A high red blood cell count, also called polycythemia, can be caused by poor circulation to the kidneys, genetic heart problems, Chronic Obstructive Pulmonary Disease ( COPD ), and pulmonary fibrosis . Some people are also born with genetic variants that cause them to have higher than normal red blood cell counts. A lower than normal count can be a sign of poor nutrition, problems with bone marrow, and leukemia , among other things. Ad

Red blood cell

What is the scientific name for the windpipe?

Red Blood Cells Red Blood Cells Red Blood Cells The red blood cells carry oxygen to the body's tissues and remove carbon dioxide and other wastes. Credits Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine Specialist Medical ReviewerBrian Leber, MDCM, FRCPC - Hematology Current as ofFebruary 20, 2015 WebMD Medical Reference from Healthwise This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.© 1995-2015 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated. Top Picks

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Where do the Graafian follicles develop?

Graafian follicle | definition of graafian follicle by Medical dictionary Graafian follicle | definition of graafian follicle by Medical dictionary http://medical-dictionary.thefreedictionary.com/graafian+follicle Related to graafian follicle: ovarian follicle , ovulation , corpus luteum graafian follicle  [graf´e-an] a small sac, embedded in the ovary , that encloses an ovum . At puberty each ovary has a large number of immature follicles ( primordial follicles ), each of which contains an undeveloped egg cell. About every 28 days between puberty and the onset of menopause, one of the follicles develops to maturity, or ripens, into a graafian follicle (or vesicular ovarian follicle ). As it ripens, it increases in size. The ovum within becomes larger, the follicular wall becomes thicker, and fluid collects in the follicle and surrounds the ovum. The follicle also secretes estradiol, the hormone that prepares the endometrium to receive a fertilized egg. As the follicle matures, it moves to the surface of the ovary and forms a projection. When fully mature, the graafian follicle breaks open and releases the ovum, which passes into the fallopian tubes . This release of the ovum is called ovulation ; it occurs midway in the menstrual cycle, generally about 14 days after the commencement of the menstrual flow. The released ovum travels down the tube to the uterus, a process that takes about 3 days. Meanwhile, the empty graafian follicle in the ovary becomes filled with cells containing a yellow substance, the corpus luteum . The corpus luteum secretes progesterone , a hormone that causes further change in the endometrium, allowing it to provide a good milieu in which a zygote (fertilized ovum) can grow through the stages of gestation to become a fetus . ve·sic·u·lar o·var·i·an fol·li·cle [TA] a follicle in which the primary oocyte attains its full size and is surrounded by an extracellular glycoprotein layer (zona pellucida) that separates it from a peripheral layer of follicular cells permeated by one or more fluid-filled antra; the primary oocyte occupies the cumulus oophorus; the theca of the follicle develops into internal and external layers. Any of the fluid-filled vesicles in the mammalian ovary containing a maturing ovum. graafian follicle [grä′fē·ən, -grā′-] Etymology: Reijnier de Graaf, Dutch physician, 1641-1673; L, folliculus, small bag a mature ovarian vesicle, measuring about 10 to 12 mm in diameter, that ruptures during ovulation to release the ovum. Many primary ovarian follicles, each containing an immature ovum about 35 μm in diameter, are embedded near the surface of the ovary, just below the tunica albuginea. Under the influence of the follicle-stimulating hormone from the adenohypophysis, one ovarian follicle ripens into a graafian follicle during the proliferative phase of each menstrual cycle. The cells that form the graafian follicle are arranged in a layer three to four cells thick around a relatively large volume of follicular fluid. Within the follicle the ovum grows to about 100 μm in diameter, ruptures, and is swept into the fimbriated opening of the uterine tube. The cavity of the follicle collapses when the ovum is released, and the remaining follicular cells greatly enlarge to become the corpus luteum. If the ovum is fertilized, the corpus luteum grows and becomes the corpus luteum of pregnancy, which degenerates by the end of 9 months and has a diameter of about 30 mm. As the ovarian follicle ripens into the graafian follicle, it produces estrogen, which stimulates the proliferation of the endometrium and the enlargement of the uterine glands. The growing corpus luteum produces progesterone, which triggers endometrial gland secretion and prepares the uterus to receive the fertilized ovum. If the ovum is not fertilized, the graafian follicle forms the corpus luteum of menstruation, which degenerates before the next menstrual cycle, leaving the small scarred corpus albicans. ve·sic·u·lar o·var·i·an fol·li·cle (vĕ-sik'yū-lăr ō-var'ē-ăn fol'i-kĕl) [TA] A follicle in which the oocyte attains its full size and is surrounded by an extracellular glycoprotein layer (zona pellucida) that separates it from a peripheral layer of follicular cells permeated by one or more fluid-filled antra; the theca of the follicle develops into internal and external layers. Synonym(s): antral follicle , graafian follicle , secondary follicle . Graafian follicle A nest of cells in the ovary that develops into a fluid-filled cyst containing a maturing egg (ovum). One or more of these develops in each menstrual cycle, releasing one or more ova into the FALLOPIAN TUBE and leaving behind the CORPUS LUTEUM . (Regnier de Graaf, 1641–73, Dutch anatomist). Fig. 179 Graafian follicle . General structure. Graafian follicle a structure in the ovary of a female mammal, consisting of an OOCYTE surrounded by granular FOLLICLE cells which enclose also a large, fluid filled cavity, the whole structure being encased in a wall of connective tissue. See Fig. 179 . The Graafian follicle begins to form deep inside the ovary, stimulated by FSH as the OESTROUS CYCLE develops, gradually enlarging and maturing as it moves to the surface, eventually appearing like a blister on the surface, just prior to release of the oocyte (ovulation) by rupture of the wall. After ovulation the follicle becomes a CORPUS LUTEUM . Further ovulation is normally prevented by the corpus luteum secreting PROGESTERONE , which in turn inhibits FSH production by the PITUITARY GLAND , so no further follicles develop. The presence of the cavity distinguishes the Graafian follicle (named after Regnier de Graaf) from the OVARIAN FOLLICLES of other vertebrates. Graaf, Reijnier de, Dutch physiologist and histologist, 1641-1673. graafian follicle - a follicle in which the oocyte attains its full size. Synonym(s): vesicular ovarian follicle graafian follicle a small sac, embedded in the ovary , that encloses an ovum. At sexual maturity each ovary has a large number of immature follicles, each of which contains an undeveloped egg cell. These structures are called primordial, or primitive, follicles. At varying intervals in the different animal species, one of these follicles develops to maturity, or ripens; as it does so the animal shows the signs of sexual receptivity known as estrus . As the follicle ripens, it increases in size. The ovum within becomes larger, the follicular wall becomes thicker, and fluid collects in the follicle and surrounds the egg. At this point, it is also known as a vesicular ovarian follicle. The follicle also secretes estradiol, the hormone that prepares the endometrium to receive a fertilized egg. As the follicle matures, it moves to the surface of the ovary and forms a projection. When fully mature, the graafian follicle breaks open and releases the ovum, which passes into the uterine tubes. This release of the ovum is called ovulation . The released ovum travels down the tube to the uterus. Meanwhile, the empty graafian follicle in the ovary becomes transformed into the corpus luteum, or yellow body, by becoming filled with cells containing a yellow substance. The corpus luteum secretes progesterone, a hormone that causes further change in the endometrium, allowing it to provide a good milieu in which a fertilized ovum can grow through the stages of gestation to become a fetus. atretic graafian follicle a follicle which enlarges and then regresses without proceeding to ovulation; occurs normally in animals as waves of follicles developing and regressing during estrous cycles and sometimes during pregnancy; occurs also in seasonally anestrous females. Follicular atresia can be a disease when it occurs at a time when the female should be coming into estrus but is on an inadequate diet, or suffering from a debilitating primary disease. The effect is a failure of the animal to come into estrus and to be fertile. cystic graafian follicle

Ovary

Where would you find the pisiform bone?

Antral Follicle Counts, Testing Ovarian Reserve Predicts IVF Response Antral Follicle Counts, Resting Follicles and Ovarian Reserve Testing egg supply and predicting response to ovarian stimulation Page author Richard Sherbahn MD Ovarian reserve, antral follicles and egg supply Women are born with all the eggs they will ever have. Eggs are lost constantly until menopause, when none remain. " Ovarian reserve " refers to the reserve of the ovaries (remaining egg supply) to be able to make babies. We want a test that shows how many eggs a woman has at a point in time - as well as telling us about the quality of the eggs. Antral follicle counts by ultrasound are one of the best ovarian reserve tests that we currently have available. Related Pages IVF stimulation protocols What Are Antral Follicles? Antral follicles are small follicles (about 2-9 mm in diameter) that we can see - and measure and count - with ultrasound. Antral follicles are also referred to as resting follicles. Vaginal ultrasound is the best way to accurately assess and count these small structures. Watch a video of antral follicle counting being done Antral follicle counts (along with female age) are by far the best tool that we currently have for estimating ovarian reserve, the expected response to ovarian stimulating drugs, and the chance for successful pregnancy with in vitro fertilization. The number of antral follicles visible on ultrasound is indicative of the number of microscopic (and sound asleep) primordial follicles remaining in the ovary. Each primordial follicle contains an immature egg that can potentially develop and ovulate in the future. When there are only a few antral follicles visible, there are far fewer eggs remaining as compared to when there are more antrals. As women age, they have less eggs (primordial follicles) remaining and they have fewer antral follicles. Antral follicle counts are a good predictor of the number of mature follicles that we will be able to stimulate in the woman's ovaries when we give injectable FSH medications that are used for in vitro fertilization. The number of eggs retrieved correlates with IVF success rates . When there are an average (or high) number of antral follicles, we tend to get a "good" response with many mature follicles. We tend to get a good number of eggs at retrieval in these cases. Pregnancy rates are higher than average. When there are few antral follicles, we tend to get a poor response with few mature follicles. Cancellation of an IVF cycle is much more common when there is a low antral count. Pregnancy rates are lower overall in this group. The reduction in success rates is more pronounced in women over 35 years old. When the number of antral follicles is intermediate, the response is not as predictable. In most cases the response is intermediate. However, we could also have either a low or a good response when the antral counts are intermediate. Pregnancy rates are pretty good overall in this group. More on egg quantity and quality issues and ovarian reserve High ovarian volume and high antral follicle counts Ultrasound image of an ovary at the beginning of a menstrual cycle. No medications being given. The ovary is outlined in blue. There are numerous antral follicles visible - marked with red. 16 are seen in this image. Ovary had a total of 35 antrals (only 1 plane is shown). This is a polycystic ovary , with a high antral count and high volume (ovary = 37 by 19.5mm) This woman had irregular periods and was a "high responder" to injectable FSH drugs. Normal ovarian volume and "normal" antral follicle counts Ultrasound image of an ovary early in the menstrual cycle. No medications being given. The ovary is outlined in blue. 9 antral follicles are seen - marked with red. The ovary has normal volume (cursors measuring ovary = 30 by 18mm). Expect a normal response to injectable FSH. Low ovarian volume and low antral follicle counts An ovary is outlined in blue and is small (low volume) with only 1 antral Her other ovary had only 2 antrals She had regular periods and a normal day 3 FSH test Attempts to stimulate her "sleepy" ovaries for IVF were not successful How many antral follicles is "good"? There is not a perfect answer to this question. Unfortunately, we do not live in a perfect world, and some ovaries have not yet read up on antral follicle counts to know how they are supposed to respond to stimulation. Antral follicle counts can also be somewhat "observer-dependent". This means that if we had several different trained ultrasonographers do an antral count on a woman, they would not all get exactly the same result. Therefore, what we decide looks like 6 antral follicles, at another clinic might have been read as 4 or 8, etc. From our own observations and experience, here are some general guidelines: Total number of antral follicles Expected response to injectable stimulating drugs and chances for IVF success Less than 4 Higher risk for overstimulation and ovarian hyperstimulation syndrome if a Lupron trigger is not utilized. Very good pregnancy rate overall. Correlation of antral counts and IVF outcomes As shown below, there is a strong association between antral numbers and: Ovarian response to stimulating medications Chances for IVF success Risk of having a canceled cycle The association between success rates and female age is obvious. Most of the decline with advancing age is due to increasing rates of chromosomal abnormalities in older eggs. Some couples have their embryos screened for chromosomal errors with PGS, preimplantation genetic screening In the charts below:

i don't know

What is the scientific name for the kneecap?

What is the scientific name for the knee cap? - YouTube What is the scientific name for the knee cap? Want to watch this again later? Sign in to add this video to a playlist. Need to report the video? Sign in to report inappropriate content. The interactive transcript could not be loaded. Loading... Rating is available when the video has been rented. This feature is not available right now. Please try again later. Published on Aug 1, 2013 This improves the knowledge of the children indirectly as they never know that they are learning. - Category

Patella

What is protected by the cranium?

Kneecap Dislocation - Signs and Treatment Kneecap Dislocation By Jonathan Cluett, MD - Reviewed by a board-certified physician. Updated March 29, 2016 A dislocation of the kneecap occurs when the patella comes completely out of its groove on the end of the thigh bone (femur), and comes to rest on the outside of the knee joint. Kneecap dislocations usually occur as a significant injury the first time the injury occurs, but the kneecap may dislocate much more easily thereafter. Signs of a Kneecap Dislocation A kneecap dislocation causes significant pain and deformity of the knee joint . The kneecap always dislocates to the outside of the joint. Pain and swelling are common symptoms of a kneecap dislocation. Over time, bruising may also develop around and below the knee joint. A kneecap dislocation should not be confused with a knee dislocation . A knee dislocation occurs when the thigh bone (femur) and shin bone (tibia) lose contact. A kneecap dislocation occurs with the kneecap dislodges from its groove on the thigh bone. Sometimes people use the words knee dislocation to describe a kneecap dislocation; this is incorrect. Recurrent Kneecap Dislocations When the kneecap comes out of joint the first time, ligaments that were holding the kneecap in position are torn. The most important torn structure is called the medial patellofemoral ligament, or MPFL. This ligament secures the patella to the inside (medial) of the knee. When a kneecap dislocation occurs, the MPFL must be torn. Once the MPFL is torn, it often does not heal with proper tension, and the kneecap can subsequently dislocate more easily. That is why recurrent dislocation of the kneecap occurs in a high percentage of patients who have this injury. Treatment of a Kneecap Dislocation Most kneecap dislocations are initially with prompt reduction (repositioning) of the kneecap. Most patients will go to emergency room, and while repositioning the kneecap is relatively straightforward, pain and muscle spasm can prevent this from being easily accomplished. Therefore, anesthesia (either local or general) may be administered to help reposition the bone. Most kneecap dislocations can be repositioned by simply straightening the knee once control of the pain and spasm allows. After repositioning the kneecap, treatment usually begins with R.I.C.E. treatment to control pain and help with swelling. Crutches and a knee brace are usually offered to help control pain. While preventing weight on the leg may help with pain, it is not necessary to keep all weight off of the leg. Once the acute swelling has subsided, treatment may progress. The next phase of treatment usually consists of physical therapy and bracing the kneecap. As discussed earlier, kneecap dislocations can become a recurrent problem. By strengthening the muscles around the joint, and with the use of specialized knee braces, the hope is to help prevent recurrent injury. In patients who have recurrent (repeat) dislocations, there are surgical options . The usual treatment is to loosen the lateral (outside) ligaments that pull the kneecap, called a lateral release procedure . Some surgeons also recommend either tightening the muscle or reconstructing the ligaments that pull from the inside of the kneecap. In some rare circumstances, a realignment of the extremity, involving cutting and repositioning bone, may be recommended. Is Surgery an Option After a First-Time Dislocation? Recent interest has developed in preventing these recurrent dislocations. Each time the kneecap dislocates, the cartilage can be injured, and the ligaments can become more stretched out. Concerns about increasing the liklihood of arthritis development from repeated trauma have made some doctors more aggressive in trying to prevent repeat dislocations. Some surgeons are trying to restore the normal anatomy by repairing the MPFL after a first-time dislocation. This surgery is controversial because not all patients who dislocate their kneecap will have another dislocation. In addition, early surgery has not been shown through scientific study to be helpful in preventing arthritis. Sources:

i don't know

What is the name of the large muscle just beneath the lungs?

Your Lungs & Respiratory System Your Lungs & Respiratory System What's something that you do all day, every day, no matter where you are or who you're with? (a) think about what's for lunch tomorrow (b) put your finger in your nose (c) hum your favorite song (d) breathe It's possible that some kids could say (a) or (c) or that others might even say — yikes! — (b). But every single person in the world has to say (d). Breathing air is necessary for keeping humans (and many animals) alive. And the two parts that are large and in charge when it comes to breathing? If you guessed your lungs, you're right! Your lungs make up one of the largest organs in your body, and they work with your respiratory system to allow you to take in fresh air, get rid of stale air, and even talk. Let's take a tour of the lungs! Locate Those Lungs Your lungs are in your chest, and they are so large that they take up most of the space in there. You have two lungs, but they aren't the same size the way your eyes or nostrils are. Instead, the lung on the left side of your body is a bit smaller than the lung on the right. This extra space on the left leaves room for your heart. Your lungs are protected by your rib cage, which is made up of 12 sets of ribs. These ribs are connected to your spine in your back and go around your lungs to keep them safe. Beneath the lungs is the diaphragm (say: DY-uh-fram), a dome-shaped muscle that works with your lungs to allow you to inhale (breathe in) and exhale (breathe out) air. You can't see your lungs, but it's easy to feel them in action: Put your hands on your chest and breathe in very deeply. You will feel your chest getting slightly bigger. Now breathe out the air, and feel your chest return to its regular size. You've just felt the power of your lungs! continue A Look Inside the Lungs From the outside, lungs are pink and a bit squishy, like a sponge. But the inside contains the real lowdown on the lungs! At the bottom of the trachea (say: TRAY-kee-uh), or windpipe, there are two large tubes. These tubes are called the main stem bronchi (say: BRONG-kye), and one heads left into the left lung, while the other heads right into the right lung. Each main stem bronchus (say: BRONG-kuss) — the name for just one of the bronchi — then branches off into tubes, or bronchi, that get smaller and even smaller still, like branches on a big tree. The tiniest tubes are called bronchioles (say: BRONG-kee-oles), and there are about 30,000 of them in each lung. Each bronchiole is about the same thickness as a hair. At the end of each bronchiole is a special area that leads into clumps of teeny tiny air sacs called alveoli (say: al-VEE-oh-lie). There are about 600 million alveoli in your lungs and if you stretched them out, they would cover an entire tennis court. Now that's a load of alveoli! Each alveolus (say: al-VEE-oh-luss) — what we call just one of the alveoli — has a mesh-like covering of very small blood vessels called capillaries (say: CAP-ill-er-ees). These capillaries are so tiny that the cells in your blood need to line up single file just to march through them. All About Inhaling When you're walking your dog, cleaning your room, or spiking a volleyball, you probably don't think about inhaling (breathing in) — you've got other things on your mind! But every time you inhale air, dozens of body parts work together to help get that air in there without you ever thinking about it. As you breathe in, your diaphragm contracts and flattens out. This allows it to move down, so your lungs have more room to grow larger as they fill up with air. "Move over, diaphragm, I'm filling up!" is what your lungs would say. And the diaphragm isn't the only part that gives your lungs the room they need. Your rib muscles also lift the ribs up and outward to give the lungs more space. At the same time, you inhale air through your mouth and nose, and the air heads down your trachea, or windpipe. On the way down the windpipe, tiny hairs called cilia (say: SILL-ee-uh) move gently to keep mucus and dirt out of the lungs. The air then goes through the series of branches in your lungs, through the bronchi and the bronchioles. previous continue Thank You, Alveoli! The air finally ends up in the 600 million alveoli. As these millions of alveoli fill up with air, the lungs get bigger. Remember that experiment where you felt your lungs get larger? Well, you were really feeling the power of those awesome alveoli! It's the alveoli that allow oxygen from the air to pass into your blood. All the cells in the body need oxygen every minute of the day. Oxygen passes through the walls of each alveolus into the tiny capillaries that surround it. The oxygen enters the blood in the tiny capillaries, hitching a ride on red blood cells and traveling through layers of blood vessels to the heart. The heart then sends the oxygenated (filled with oxygen) blood out to all the cells in the body.   Waiting to Exhale When it's time to exhale (breathe out), everything happens in reverse: Now it's the diaphragm's turn to say, "Move it!" Your diaphragm relaxes and moves up, pushing air out of the lungs. Your rib muscles become relaxed, and your ribs move in again, creating a smaller space in your chest. By now your cells have used the oxygen they need, and your blood is carrying carbon dioxide and other wastes that must leave your body. The blood comes back through the capillaries and the wastes enter the alveoli. Then you breathe them out in the reverse order of how they came in — the air goes through the bronchioles, out the bronchi, out the trachea, and finally out through your mouth and nose. The air that you breathe out not only contains wastes and carbon dioxide, but it's warm, too! As air travels through your body, it picks up heat along the way. You can feel this heat by putting your hand in front of your mouth or nose as you breathe out. What is the temperature of the air that comes out of your mouth or nose? With all this movement, you might be wondering why things don't get stuck as the lungs fill and empty! Luckily, your lungs are covered by two really slick special layers called pleural (say: PLOO-ral) membranes. These membranes are separated by a fluid that allows them to slide around easily while you inhale and exhale. previous continue Time for Talk Your lungs are important for breathing . . . and also for talking! Above the trachea (windpipe) is the larynx (say: LAIR-inks), which is sometimes called the voice box. Across the voice box are two tiny ridges called vocal cords, which open and close to make sounds. When you exhale air from the lungs, it comes through the trachea and larynx and reaches the vocal cords. If the vocal cords are closed and the air flows between them, the vocal cords vibrate and a sound is made. The amount of air you blow out from your lungs determines how loud a sound will be and how long you can make the sound. Try inhaling very deeply and saying the names of all the kids in your class — how far can you get without taking the next breath? The next time you're outside, try shouting and see what happens — shouting requires lots of air, so you'll need to breathe in more frequently than you would if you were only saying the words. Experiment with different sounds and the air it takes to make them — when you giggle, you let out your breath in short bits, but when you burp , you let swallowed air in your stomach out in one long one! When you hiccup, it's because the diaphragm moves in a funny way that causes you to breathe in air suddenly, and that air hits your vocal cords when you're not ready. Love Your Lungs Your lungs are amazing. They allow you to breathe, talk to your friend, shout at a game, sing, laugh, cry, and more! And speaking of a game, your lungs even work with your brain to help you inhale and exhale a larger amount of air at a more rapid rate when you're running a mile — all without you even thinking about it once. Keeping your lungs looking and feeling healthy is a smart idea, and the best way to keep your lungs pink and healthy is not to smoke. Smoking isn't good for any part of your body, and your lungs especially hate it. Cigarette smoke damages the cilia in the trachea so they can no longer move to keep dirt and other substances out of the lungs. Your alveoli get hurt too, because the chemicals in cigarette smoke can cause the walls of the delicate alveoli to break down, making it much harder to breathe. Finally, cigarette smoke can damage the cells of the lungs so much that the healthy cells go away, only to be replaced by cancer cells. Lungs are normally tough and strong, but when it comes to cigarettes, they can be hurt easily — and it's often very difficult or impossible to make them better. If you need to work with chemicals in an art or shop class, be sure to wear a protective mask to keep chemical fumes from entering your lungs. You can also show your love for your lungs by exercising! Exercise is good for every part of your body, and especially for your lungs and heart. When you take part in vigorous exercise (like biking, running, or swimming, for example), your lungs require more air to give your cells the extra oxygen they need. As you breathe more deeply and take in more air, your lungs become stronger and better at supplying your body with the air it needs to succeed. Keep your lungs healthy and they will thank you for life!

Diaphragm

Where in the body is the thyroid?

Human Physiology/The respiratory system - Wikibooks, open books for an open world Human Physiology/The respiratory system Homeostasis — Cells — Integumentary — Nervous — Senses — Muscular — Blood — Cardiovascular — Immune — Urinary — Respiratory — Gastrointestinal — Nutrition — Endocrine — Reproduction (male) — Reproduction (female) — Pregnancy — Genetics — Development — Answers The Respiratory System is vital to every human being. Without it, we would cease to live outside of the womb. Let us begin by taking a look at the structure of the respiratory system and how vital it is to life. During inhalation or exhalation air is pulled towards or away from the lungs, by several cavities, tubes, and openings. The organs of the respiratory system make sure that oxygen enters our bodies and carbon dioxide leaves our bodies. The respiratory tract is the path of air from the nose to the lungs. It is divided into two sections: Upper Respiratory Tract and the Lower Respiratory Tract. Included in the upper respiratory tract are the Nostrils, Nasal Cavities, Pharynx, Epiglottis, and the Larynx. The lower respiratory tract consists of the Trachea, Bronchi, Bronchioles, and the Lungs. As air moves along the respiratory tract it is warmed, moistened and filtered. The lungs flank the heart and great vessels in the chest cavity. (Source: Gray's Anatomy of the Human Body, 20th ed. 1918.) Contents In this chapter we will discuss the four processes of respiration. They are: BREATHING or ventilation EXTERNAL RESPIRATION, which is the exchange of gases (oxygen and carbon dioxide) between inhaled air and the blood. INTERNAL RESPIRATION, which is the exchange of gases between the blood and tissue fluids. CELLULAR RESPIRATION In addition to these main processes, the respiratory system serves for: REGULATION OF BLOOD pH, which occurs in coordination with the kidneys, and as a DEFENSE AGAINST MICROBES Control of body temperature due to loss of evaporate during expiration Breathing and Lung Mechanics[ edit ] Ventilation is the exchange of air between the external environment and the alveoli. Air moves by bulk flow from an area of high pressure to low pressure. All pressures in the respiratory system are relative to atmospheric pressure (760mmHg at sea level). Air will move in or out of the lungs depending on the pressure in the alveoli. The body changes the pressure in the alveoli by changing the volume of the lungs. As volume increases pressure decreases and as volume decreases pressure increases. There are two phases of ventilation; inspiration and expiration. During each phase the body changes the lung dimensions to produce a flow of air either in or out of the lungs. The body is able to stay at the dimensions of the lungs because of the relationship of the lungs to the thoracic wall. Each lung is completely enclosed in a sac called the pleural sac. Two structures contribute to the formation of this sac. The parietal pleura is attached to the thoracic wall where as the visceral pleura is attached to the lung itself. In-between these two membranes is a thin layer of intrapleural fluid. The intrapleural fluid completely surrounds the lungs and lubricates the two surfaces so that they can slide across each other. Changing the pressure of this fluid also allows the lungs and the thoracic wall to move together during normal breathing. Much the way two glass slides with water in-between them are difficult to pull apart, such is the relationship of the lungs to the thoracic wall. The rhythm of ventilation is also controlled by the "Respiratory Center" which is located largely in the medulla oblongata of the brain stem. This is part of the autonomic system and as such is not controlled voluntarily (one can increase or decrease breathing rate voluntarily, but that involves a different part of the brain). While resting, the respiratory center sends out action potentials that travel along the phrenic nerves into the diaphragm and the external intercostal muscles of the rib cage, causing inhalation. Relaxed exhalation occurs between impulses when the muscles relax. Normal adults have a breathing rate of 12-20 respirations per minute. The Pathway of Air[ edit ] When one breathes air in at sea level, the inhalation is composed of different gases. These gases and their quantities are Oxygen which makes up 21%, Nitrogen which is 78%, Carbon Dioxide with 0.04% and others with significantly smaller portions. Diagram of the Pharynx. In the process of breathing, air enters into the nasal cavity through the nostrils and is filtered by coarse hairs (vibrissae) and mucous that are found there. The vibrissae filter macroparticles, which are particles of large size. Dust, pollen, smoke, and fine particles are trapped in the mucous that lines the nasal cavities (hollow spaces within the bones of the skull that warm, moisten, and filter the air). There are three bony projections inside the nasal cavity. The superior, middle, and inferior nasal conchae. Air passes between these conchae via the nasal meatuses. Air then travels past the nasopharynx, oropharynx, and laryngopharynx, which are the three portions that make up the pharynx. The pharynx is a funnel-shaped tube that connects our nasal and oral cavities to the larynx. The tonsils which are part of the lymphatic system, form a ring at the connection of the oral cavity and the pharynx. Here, they protect against foreign invasion of antigens. Therefore, the respiratory tract aids the immune system through this protection. Then the air travels through the larynx. The larynx closes at the epiglottis to prevent the passage of food or drink as a protection to our trachea and lungs. The larynx is also our voicebox; it contains vocal cords, in which it produces sound. Sound is produced from the vibration of the vocal cords when air passes through them. The trachea, which is also known as our windpipe, has ciliated cells and mucous secreting cells lining it, and is held open by C-shaped cartilage rings. One of its functions is similar to the larynx and nasal cavity, by way of protection from dust and other particles. The dust will adhere to the sticky mucous and the cilia helps propel it back up the trachea, to where it is either swallowed or coughed up. The mucociliary escalator extends from the top of the trachea all the way down to the bronchioles, which we will discuss later. Through the trachea, the air is now able to pass into the bronchi, bronchioles and finally alveoli before entering the pulmonary capillaries. Inspiration[ edit ] Inspiration is initiated by contraction of the diaphragm and in some cases the intercostals muscles when they receive nervous impulses. During normal quiet breathing, the phrenic nerves stimulate the diaphragm to contract and move downward into the abdomen. This downward movement of the diaphragm enlarges the thorax. When necessary, the intercostal muscles also increase the thorax by contacting and drawing the ribs upward and outward. As the diaphragm contracts inferiorly and thoracic muscles pull the chest wall outwardly, the volume of the thoracic cavity increases. The lungs are held to the thoracic wall by negative pressure in the pleural cavity, a very thin space filled with a few milliliters of lubricating pleural fluid. The negative pressure in the pleural cavity is enough to hold the lungs open in spite of the inherent elasticity of the tissue. Hence, as the thoracic cavity increases in volume the lungs are pulled from all sides to expand, causing a drop in the pressure (a partial vacuum) within the lung itself (but note that this negative pressure is still not as great as the negative pressure within the pleural cavity--otherwise the lungs would pull away from the chest wall). Assuming the airway is open, air from the external environment then follows its pressure gradient down and expands the alveoli of the lungs, where gas exchange with the blood takes place. As long as pressure within the alveoli is lower than atmospheric pressure air will continue to move inwardly, but as soon as the pressure is stabilized air movement stops. Expiration[ edit ] During quiet breathing, expiration is normally a passive process and does not require muscles to work (rather it is the result of the muscles relaxing). When the lungs are stretched and expanded, stretch receptors within the alveoli send inhibitory nerve impulses to the medulla oblongata, causing it to stop sending signals to the rib cage and diaphragm to contract. The muscles of respiration and the lungs themselves are elastic, so when the diaphragm and intercostal muscles relax there is an elastic recoil, which creates a positive pressure (pressure in the lungs becomes greater than atmospheric pressure), and air moves out of the lungs by flowing down its pressure gradient. Although the respiratory system is primarily under involuntary control, and regulated by the medulla oblongata, we have some voluntary control over it also. This is due to the higher brain function of the cerebral cortex. When under physical or emotional stress, more frequent and deep breathing is needed, and both inspiration and expiration will work as active processes. Additional muscles in the rib cage forcefully contract and push air quickly out of the lungs. In addition to deeper breathing, when coughing or sneezing we exhale forcibly. Our abdominal muscles will contract suddenly (when there is an urge to cough or sneeze), raising the abdominal pressure. The rapid increase in pressure pushes the relaxed diaphragm up against the pleural cavity. This causes air to be forced out of the lungs. Another function of the respiratory system is to sing and to speak. By exerting conscious control over our breathing and regulating flow of air across the vocal cords we are able to create and modify sounds. Lung Compliance[ edit ] Lung Compliance is the magnitude of the change in lung volume produced by a change in pulmonary pressure. Compliance can be considered the opposite of stiffness. A low lung compliance would mean that the lungs would need a greater than average change in intrapleural pressure to change the volume of the lungs. A high lung compliance would indicate that little pressure difference in intrapleural pressure is needed to change the volume of the lungs. More energy is required to breathe normally in a person with low lung compliance. Persons with low lung compliance due to disease therefore tend to take shallow breaths and breathe more frequently. Determination of Lung Compliance Two major things determine lung compliance. The first is the elasticity of the lung tissue. Any thickening of lung tissues due to disease will decrease lung compliance. The second is surface tensions at air water interfaces in the alveoli. The surface of the alveoli cells is moist. The attractive force, between the water cells on the alveoli, is called surface tension. Thus, energy is required not only to expand the tissues of the lung but also to overcome the surface tension of the water that lines the alveoli. To overcome the forces of surface tension, certain alveoli cells (Type II pneumocytes) secrete a protein and lipid complex called ""Surfactant””, which acts like a detergent by disrupting the hydrogen bonding of water that lines the alveoli, hence decreasing surface tension. Control of respiration[ edit ] Peripheral control[ edit ] CO2 is converted to HCO3; most CO2 produced at the tissue cells is carried to lungs in the form of HCO3 CO2 & H2O form carbonic acid (H2CO3) changes to H CO3 & H+ ions result is H+ ions are buffered by plasma proteins Respiratory System: Upper and Lower Respiratory Tracts[ edit ] For the sake of convenience, we will divide the respiratory system in to the upper and lower respiratory tracts: Upper Respiratory Tract[ edit ] The upper respiratory tract consists of the nose and the pharynx. Its primary function is to receive the air from the external environment and filter, warm, and humidify it before it reaches the delicate lungs where gas exchange will occur. Air enters through the nostrils of the nose and is partially filtered by the nose hairs, then flows into the nasal cavity. The nasal cavity is lined with epithelial tissue, containing blood vessels, which help warm the air; and secrete mucous, which further filters the air. The endothelial lining of the nasal cavity also contains tiny hairlike projections, called cilia. The cilia serve to transport dust and other foreign particles, trapped in mucous, to the back of the nasal cavity and to the pharynx. There the mucus is either coughed out, or swallowed and digested by powerful stomach acids. After passing through the nasal cavity, the air flows down the pharynx to the larynx. Lower Respiratory Tract[ edit ] The lower respiratory tract starts with the larynx, and includes the trachea, the two bronchi that branch from the trachea, and the lungs themselves. This is where gas exchange actually takes place. Larynx The larynx (plural larynges), colloquially known as the voice box, is an organ in our neck involved in protection of the trachea and sound production. The larynx houses the vocal cords, and is situated just below where the tract of the pharynx splits into the trachea and the esophagus. The larynx contains two important structures: the epiglottis and the vocal cords. The epiglottis is a flap of cartilage located at the opening to the larynx. During swallowing, the larynx (at the epiglottis and at the glottis) closes to prevent swallowed material from entering the lungs; the larynx is also pulled upwards to assist this process. Stimulation of the larynx by ingested matter produces a strong cough reflex to protect the lungs. Note: choking occurs when the epiglottis fails to cover the trachea, and food becomes lodged in our windpipe. The vocal cords consist of two folds of connective tissue that stretch and vibrate when air passes through them, causing vocalization. The length the vocal cords are stretched determines what pitch the sound will have. The strength of expiration from the lungs also contributes to the loudness of the sound. Our ability to have some voluntary control over the respiratory system enables us to sing and to speak. In order for the larynx to function and produce sound, we need air. That is why we can't talk when we're swallowing. Trachea Homeostasis and Gas Exchange[ edit ] Gas exchange Homeostasis is maintained by the respiratory system in two ways: gas exchange and regulation of blood pH. Gas exchange is performed by the lungs by eliminating carbon dioxide, a waste product given off by cellular respiration. As carbon dioxide exits the body, oxygen needed for cellular respiration enters the body through the lungs. ATP, produced by cellular respiration, provides the energy for the body to perform many functions, including nerve conduction and muscle contraction. Lack of oxygen affects brain function, sense of judgment, and a host of other problems. Gas Exchange[ edit ] Gas exchange in the lungs and in the alveoli is between the alveolar air and the blood in the pulmonary capillaries. This exchange is a result of increased concentration of oxygen, and a decrease of C02. This process of exchange is done through diffusion. External Respiration[ edit ] External respiration is the exchange of gas between the air in the alveoli and the blood within the pulmonary capillaries. A normal rate of respiration is 12-25 breaths per minute. In external respiration, gases diffuse in either direction across the walls of the alveoli. Oxygen diffuses from the air into the blood and carbon dioxide diffuses out of the blood into the air. Most of the carbon dioxide is carried to the lungs in plasma as bicarbonate ions (HCO3-). When blood enters the pulmonary capillaries, the bicarbonate ions and hydrogen ions are converted to carbonic acid (H2CO3) and then back into carbon dioxide (CO2) and water. This chemical reaction also uses up hydrogen ions. The removal of these ions gives the blood a more neutral pH, allowing hemoglobin to bind up more oxygen. De-oxygenated blood "blue blood" coming from the pulmonary arteries, generally has an oxygen partial pressure (pp) of 40 mmHg and CO2 pp of 45 mmHg. Oxygenated blood leaving the lungs via the pulmonary veins has an O2 pp of 100 mmHg and CO2 pp of 40 mmHg. It should be noted that alveolar O2 pp is 105 mmHg, and not 100 mmHg. The reason why pulmonary venous return blood has a lower than expected O2 pp can be explained by "Ventilation Perfusion Mismatch". Internal respiration is the exchanging of gases at the cellular level. The Passage Way From the Trachea to the Bronchioles[ edit ] There is a point at the inferior portion of the trachea where it branches into two directions that form the right and left primary bronchus. This point is called the Carina which is the keel-like cartilage plate at the division point. We are now at the Bronchial Tree. It is named so because it has a series of respiratory tubes that branch off into smaller and smaller tubes as they run throughout the lungs. Right and Left Lungs[ edit ] Diagram of the lungs The Right Primary Bronchus is the first portion we come to, it then branches off into the Lobar (secondary) Bronchi, Segmental (tertiary) Bronchi, then to the Bronchioles which have little cartilage and are lined by simple cuboidal epithelium (See fig. 1). The bronchi are lined by pseudostratified columnar epithelium. Objects will likely lodge here at the junction of the Carina and the Right Primary Bronchus because of the vertical structure. Items have a tendency to fall in it, where as the Left Primary Bronchus has more of a curve to it which would make it hard to have things lodge there. The Left Primary Bronchus has the same setup as the right with the lobar, segmental bronchi and the bronchioles. The lungs are attached to the heart and trachea through structures that are called the roots of the lungs. The roots of the lungs are the bronchi, pulmonary vessels, bronchial vessels, lymphatic vessels, and nerves. These structures enter and leave at the hilus of the lung which is "the depression in the medial surface of a lung that forms the opening through which the bronchus, blood vessels, and nerves pass" (medlineplus.gov). There are a number of terminal bronchioles connected to respiratory bronchioles which then advance into the alveolar ducts that then become alveolar sacs. Each bronchiole terminates in an elongated space enclosed by many air sacs called alveoli which are surrounded by blood capillaries. Present there as well, are Alveolar Macrophages, they ingest any microbes that reach the alveoli. The Pulmonary Alveoli are microscopic, which means they can only be seen through a microscope, membranous air sacs within the lungs. They are units of respiration and the site of gas exchange between the respiratory and circulatory systems. Cellular Respiration[ edit ] First the oxygen must diffuse from the alveolus into the capillaries. It is able to do this because the capillaries are permeable to oxygen. After it is in the capillary, about 5% will be dissolved in the blood plasma. The other oxygen will bind to red blood cells. The red blood cells contain hemoglobin that carries oxygen. Blood with hemoglobin is able to transport 26 times more oxygen than plasma without hemoglobin. Our bodies would have to work much harder pumping more blood to supply our cells with oxygen without the help of hemoglobin. Once it diffuses by osmosis it combines with the hemoglobin to form oxyhemoglobin. Now the blood carrying oxygen is pumped through the heart to the rest of the body. Oxygen will travel in the blood into arteries, arterioles, and eventually capillaries where it will be very close to body cells. Now with different conditions in temperature and pH (warmer and more acidic than in the lungs), and with pressure being exerted on the cells, the hemoglobin will give up the oxygen where it will diffuse to the cells to be used for cellular respiration, also called aerobic respiration. Cellular respiration is the process of moving energy from one chemical form (glucose) into another (ATP), since all cells use ATP for all metabolic reactions. It is in the mitochondria of the cells where oxygen is actually consumed and carbon dioxide produced. Oxygen is produced as it combines with hydrogen ions to form water at the end of the electron transport chain (see chapter on cells). As cells take apart the carbon molecules from glucose, these get released as carbon dioxide. Each body cell releases carbon dioxide into nearby capillaries by diffusion, because the level of carbon dioxide is higher in the body cells than in the blood. In the capillaries, some of the carbon dioxide is dissolved in plasma and some is taken by the hemoglobin, but most enters the red blood cells where it binds with water to form carbonic acid. It travels to the capillaries surrounding the lung where a water molecule leaves, causing it to turn back into carbon dioxide. It then enters the lungs where it is exhaled into the atmosphere. Lung Capacity[ edit ] The normal volume moved in or out of the lungs during quiet breathing is called tidal volume. When we are in a relaxed state, only a small amount of air is brought in and out, about 500 mL. You can increase both the amount you inhale, and the amount you exhale, by breathing deeply. Breathing in very deeply is Inspiratory Reserve Volume and can increase lung volume by 2900 mL, which is quite a bit more than the tidal volume of 500 mL. We can also increase expiration by contracting our thoracic and abdominal muscles. This is called expiratory reserve volume and is about 1400 ml of air. Vital capacity is the total of tidal, inspiratory reserve and expiratory reserve volumes; it is called vital capacity because it is vital for life, and the more air you can move, the better off you are. There are a number of illnesses that we will discuss later in the chapter that decrease vital capacity. Vital Capacity can vary a little depending on how much we can increase inspiration by expanding our chest and lungs. Some air that we breathe never even reaches the lungs! Instead it fills our nasal cavities, trachea, bronchi, and bronchioles. These passages aren't used in gas exchange so they are considered to be dead air space. To make sure that the inhaled air gets to the lungs, we need to breathe slowly and deeply. Even when we exhale deeply some air is still in the lungs,(about 1000 ml) and is called residual volume. This air isn't useful for gas exchange. There are certain types of diseases of the lung where residual volume builds up because the person cannot fully empty the lungs. This means that the vital capacity is also reduced because their lungs are filled with useless air. Stimulation of Breathing[ edit ] There are two pathways of motor neuron stimulation of the respiratory muscles. The first is the control of voluntary breathing by the cerebral cortex. The second is involuntary breathing controlled by the medulla oblongata. There are chemoreceptors in the aorta, the carotid body of carotid arteries, and in the medulla oblongata of the brainstem that are sensitive to pH. As carbon dioxide levels increase there is a buildup of carbonic acid, which releases hydrogen ions and lowers pH. Thus, the chemoreceptors do not respond to changes in oxygen levels (which actually change much more slowly), but to pH, which is dependent upon plasma carbon dioxide levels. In other words, CO2 is the driving force for breathing. The receptors in the aorta and the carotid sinus initiate a reflex that immediately stimulates breathing rate and the receptors in the medulla stimulate a sustained increase in breathing until blood pH returns to normal. This response can be experienced by running a 100-meter dash. During this exertion (or any other sustained exercise) your muscle cells must metabolize ATP at a much faster rate than usual, and thus will produce much higher quantities of CO2. The blood pH drops as CO2 levels increase, and you will involuntarily increase breathing rate very soon after beginning the sprint. You will continue to breathe heavily after the race, thus expelling more carbon dioxide, until pH has returned to normal. Metabolic acidosis therefore is acutely corrected by respiratory compensation (hyperventilation). Regulation of Blood pH[ edit ] Many of us are not aware of the importance of maintaining the acid/base balance of our blood. It is vital to our survival. Normal blood pH is set at 7.4, which is slightly alkaline or "basic". If the pH of our blood drops below 7.2 or rises above 7.6 then very soon our brains would cease functioning normally and we would be in big trouble. Blood pH levels below 6.9 or above 7.9 are usually fatal if they last for more than a short time. Another wonder of our amazing bodies is the ability to cope with every pH change – large or small. There are three factors in this process: the lungs, the kidneys and buffers. So what exactly is pH? pH is the concentration of hydrogen ions (H+). Buffers are molecules which take in or release ions in order to maintain the H+ ion concentration at a certain level. When blood pH is too low and the blood becomes too acidic (acidosis), the presence of too many H+ ions is to blame. Buffers help to soak up those extra H+ ions. On the other hand, the lack of H+ ions causes the blood to be too basic (alkalosis). In this situation, buffers release H+ ions. Buffers function to maintain the pH of our blood by either donating or grabbing H+ ions as necessary to keep the number of H+ ions floating around the blood at just the right amount. The most important buffer we have in our bodies is a mixture of carbon dioxide (CO2) and bicarbonate ion (HCO3). CO2 forms carbonic acid (H2CO3) when it dissolves in water and acts as an acid giving up hydrogen ions (H+) when needed. HCO3 is a base and soaks up hydrogen ions (H+) when there are too many of them. In a nutshell, blood pH is determined by a balance between bicarbonate and carbon dioxide. Bicarbonate Buffer System. With this important system our bodies maintain homeostasis. (Note that H2CO3 is Carbonic Acid and HCO3 is Bicarbonate) CO2 + H2O <---> H2CO3 <---> (H+) + HCO3 If pH is too high, carbonic acid will donate hydrogen ions (H+) and pH will drop. If pH is too low, bicarbonate will bond with hydrogen ions (H+) and pH will rise. Too much CO2 or too little HCO3 in the blood will cause acidosis. The CO2 level is increased when hypoventilation or slow breathing occurs, such as if you have emphysema or pneumonia. Bicarbonate will be lowered by ketoacidosis, a condition caused by excess fat metabolism (diabetes mellitus). Too much HCO3 or too little CO2 in the blood will cause alkalosis. This condition is less common than acidosis. CO2 can be lowered by hyperventilation. So, in summary, if you are going into respiratory acidosis the above equation will move to the right. The body's H+ and CO2 levels will rise and the pH will drop. To counteract this the body will breathe more and release H+. In contrast, if you are going into respiratory alkalosis the equation will move to the left. The body's H+ and CO2 levels will fall and the pH will rise. So the body will try to breathe less to release HCO3. You can think of it like a leak in a pipe: where ever there is a leak, the body will "fill the hole". Problems Associated With the Respiratory Tract and Breathing[ edit ] The environment of the lung is very moist, which makes it a hospitable environment for bacteria. Many respiratory illnesses are the result of bacterial or viral infection of the lungs. Because we are constantly being exposed to harmful bacteria and viruses in our environment, our respiratory health can be adversely affected. There are a number of illnesses and diseases that can cause problems with breathing. Some are simple infections, and others are disorders that can be quite serious. Carbon Monoxide Poisoning: caused when carbon monoxide binds to hemoglobin in place of oxygen. Carbon monoxide binds much tighter, without releasing, causing the hemoglobin to become unavailable to oxygen. The result can be fatal in a very short amount of time. Mild Symptoms: flu like symptoms, dizziness, fatigue, headaches, nausea, and irregular breathing Moderate Symptoms: chest pain, rapid heart beat, difficulty thinking, blurred vision, shortness of breath and unsteadiness Severe Symptoms: seizures, palpitations, disorientation, irregular heart beat, low blood pressure, coma and death. Pulmonary Embolism: blockage of the pulmonary artery (or one of its branches) by a blood clot, fat, air or clumped tumor cells. By far the most common form of pulmonary embolism is a thromboembolism, which occurs when a blood clot, generally a venous thrombus, becomes dislodged from its site of formation and embolizes to the arterial blood supply of one of the lungs. Symptoms may include difficulty breathing, pain during breathing, and more rarely circulatory instability and death. Treatment, usually, is with anticoagulant medication. Upper Respiratory Tract Infections[ edit ] The upper respiratory tract consists of our nasal cavities, pharynx, and larynx. Upper respiratory infections (URI) can spread from our nasal cavities to our sinuses, ears, and larynx. Sometimes a viral infection can lead to what is called a secondary bacterial infection. "Strep throat" is a primary bacterial infection and can lead to an upper respiratory infection that can be generalized or even systemic (affects the body as a whole). Antibiotics aren't used to treat viral infections, but are successful in treating most bacterial infections, including strep throat. The symptoms of strep throat can be a high fever, severe sore throat, white patches on a dark red throat, and stomach ache. Sinusitis An infection of the cranial sinuses is called sinusitis. Only about 1-3% of URI's are accompanied by sinusitis. This "sinus infection" develops when nasal congestion blocks off the tiny openings that lead to the sinuses. Some symptoms include: post nasal discharge, facial pain that worsens when bending forward, and sometimes even tooth pain can be a symptom. Successful treatment depends on restoring the proper drainage of the sinuses. Taking a hot shower or sleeping upright can be very helpful. Otherwise, using a spray decongestant or sometimes a prescribed antibiotic will be necessary. Otitis Media Otitis media in an infection of the middle ear. Even though the middle ear is not part of the respiratory tract, it is discussed here because it is often a complication seen in children who has a nasal infection. The infection can be spread by way of the 'auditory (Eustachian) tube that leads form the nasopharynx to the middle ear. The main symptom is usually pain. Sometimes though, vertigo, hearing loss, and dizziness may be present. Antibiotics can be prescribed and tubes are placed in the eardrum to prevent the buildup of pressure in the middle ear and the possibility of hearing loss. Photo of Tonsillitis. Tonsillitis Tonsillitis occurs when the tonsils become swollen and inflamed. The tonsils located in the posterior wall of the nasopharynx are often referred to as adenoids. If you suffer from tonsillitis frequently and breathing becomes difficult, they can be removed surgically in a procedure called a tonsillectomy. Laryngitis An infection of the larynx is called laryngitis. It is accompanied by hoarseness and being unable to speak in an audible voice. Usually, laryngitis disappears with treatment of the URI. Persistent hoarseness without a URI is a warning sign of cancer, and should be checked into by your physician. Lower Respiratory Tract Disorders[ edit ] Lower respiratory tract disorders include infections, restrictive pulmonary disorders, obstructive pulmonary disorders, and lung cancer. Lower Respiratory Infections[ edit ] Acute bronchitis An infection that is located in the primary and secondary bronchi is called bronchitis. Most of the time, it is preceded by a viral URI that led to a secondary bacterial infection. Usually, a nonproductive cough turns into a deep cough that will expectorate mucus and sometimes pus. Pneumonia A bacterial or viral infection in the lungs where the bronchi and the alveoli fill with a thick fluid. Usually it is preceded by influenza. Symptoms of pneumonia include high fever & chills, with headache and chest pain. Pneumonia can be located in several lobules of the lung and obviously, the more lobules involved, the more serious the infection. It can be caused by a bacteria that is usually held in check, but due to stress or reduced immunity has gained the upper hand. Restrictive Pulmonary Disorders[ edit ] Pulmonary Fibrosis Vital capacity is reduced in these types of disorders because the lungs have lost their elasticity. Inhaling particles such as sand, asbestos, coal dust, or fiberglass can lead to pulmonary fibrosis, a condition where fibrous tissue builds up in the lungs. This makes it so our lungs cannot inflate properly and are always tending toward deflation. Diagram of the lungs during an asthma attack. Asthma Asthma is a respiratory disease of the bronchi and bronchioles. The symptoms include wheezing, shortness of breath, and sometimes a cough that will expel mucus. The airways are very sensitive to irritants which can include pollen, dust, animal dander, and tobacco. Even being out in cold air can be an irritant. When exposed to an irritant, the smooth muscle in the bronchioles undergoes spasms. Most asthma patients have at least some degree of bronchial inflammation that reduces the diameter of the airways and contributes to the seriousness of the attack. Emphysema Emphysema is a type of chronic obstructive pulmonary disease. Typically characterized by a loss of elasticity and surfactant in the alveoli, a loss of surface area decreases the gas exchange in the lungs. These patients have difficulty with too little expiratory pressure, not retaining inspired air long enough for sufficient gas exchange to happen. Chronic Bronchitis Another type of chronic obstructive pulmonary disease, Chronic Bronchitis is caused by overproduction of mucus in the airways, causing an inadequate expiration of inspired air. Retention of air in the lungs reduces gas exchange at the alveoli, and can lead to a hypoxic drive. These patients are known as "blue bloaters", vulnerable to cyanosis and often have increased thoracic diameters. Respiratory Distress Syndrome[ edit ] Pathophysiology At birth the pressure needed to expand the lungs requires high inspiratory pressure. In the presence of normal surfactant levels the lungs retain as much as 40% of the residual volume after the first breath and thereafter will only require far lower inspiratory pressures. In the case of deficiency of surfactant the lungs will collapse between breaths, this makes the infant work hard and each breath is as hard as the first breath. If this goes on further the pulmonary capillary membranes become more permeable, letting in fibrin rich fluids between the alveolar spaces and in turn forms a hyaline membrane. The hyaline membrane is a barrier to gas exchange, this hyaline membrane then causes hypoxemia and carbon dioxide retention that in turn will further impair surfactant production. Etiology Type two alveolar cells produce surfactant and do not develop until the 25th to the 28th week of gestation, in this, respiratory distress syndrome is one of the most common respiratory disease in premature infants. Furthermore, surfactant deficiency and pulmonary immaturity together leads to alveolar collapse. Predisposing factors that contribute to poorly functioning type II alveolar cells in a premature baby are if the child is a preterm male, white infants, infants of mothers with diabetes, precipitous deliveries, cesarean section performed before the 38th week of gestation. Surfactant synthesis is influenced by hormones, this ranges form insulin and cortisol. Insulin inhibits surfactant production, explaining why infants of mothers with diabetes type 1 are at risk of development of respiratory distress syndrome. Cortisol can speed up maturation of type II cells and therefore production of surfactant. Finally, in the baby delivered by cesarean section are at greater risk of developing respiratory distress syndrome because the reduction of cortisol produced because the lack of stress that happens during vaginal delivery, hence cortisol increases in high stress and helps in the maturation of type II cells of the alveoli that cause surfactant. Treatment Today to prevent respiratory distress syndrome are animal sources and synthetic surfactants, and administrated through the airways by an endotracheal tube and the surfactant is suspended in a saline solution. Treatment is initiated post birth and in infants who are at high risk for respiratory distress syndrome. Sleep Apnea[ edit ] CPAP is the most common treatment for obstructive sleep apnea. Sleep apnea or sleep apnoea is a sleep disorder characterized by pauses in breathing during sleep. These episodes, called apneas (literally, "without breath"), each last long enough so one or more breaths are missed, and occur repeatedly throughout sleep. The standard definition of any apneic event includes a minimum 10 second interval between breaths, with either a neurological arousal (3-second or greater shift in EEG frequency, measured at C3, C4, O1, or O2), or a blood oxygen desaturation of 3-4 percent or greater, or both arousal and desaturation. Sleep apnea is diagnosed with an overnight sleep test called polysomnogram. One method of treating central sleep apnea is with a special kind of CPAP, APAP, or VPAP machine with a Spontaneous Time (ST) feature. This machine forces the wearer to breathe a constant number of breaths per minute. (CPAP), or continuous positive airway pressure, in which a controlled air compressor generates an airstream at a constant pressure. This pressure is prescribed by the patient's physician, based on an overnight test or titration. Nutrition for COPD (Chronic Obstructive Pulmonary Disease) Patients[ edit ] Nutrition is particularly important for ventilator-dependent patient. When metabolizing macronutrients carbon dioxide and water are produced. The respiratory quotient (RQ) is a ratio of produced carbon dioxide to amount consumed. Carbohydrates metabolism produces the most amount of carbon dioxide so they have the highest (RQ). Fats produce the least amount of carbon dioxide along with proteins. Protein has a slightly higher RQ ratio. It is recommended that this kind of patient not exceed a 1.0 respiratory quotient (RQ). Lowering carbohydrates and supplementing fat or protein in the diet might not result in maintaining the desired outcome because, excess amounts fat or protein may also result in a respiratory quotient (RQ) higher than 1.0. Please reference source and fact accuracy. It seems like by definition, it is impossible to exceed a respiratory quotient (RQ) of 1.0. * Case Study[ edit ] Cystic Fibrosis This disease is most common in Caucasians and will happen to 1 in every 2500 people. It is most known for its effects on the respiratory tract although it does effect other systems as well. The respiratory passages become clogged with a thick mucus that is difficult to expel even with vigorous coughing. Breathing becomes difficult and affected individuals run the risk of choking to death on their own secretions unless strenuous effort is made to clear the lungs multiple times every day. Victims frequently will die in the 20's of pneumonia. All of us secrete mucus by certain cells in the epithelium that line the respiratory passageways. In normal cases the cells also secrete a watery fluid that will dilute the mucus making it easier to pass through the airways. In cystic fibrosis that secretion of watery fluid is impaired. This makes the mucus thicker and difficult to clear from the passageways. A recent discovery found that in cystic fibrosis is caused by a defect in a type of chloride protein found in apical membranes of epithelial calls in the respiratory system and elsewhere. This defect directly impedes the chlorine ions transport, which will then indirectly effect the transport of potassium ions. This causes the epithelium, to not create its osmotic gradient necessary for water secretion. It has been known for a long time that cystic fibrosis is caused by a recessive gene inheritance. This gene codes for a portion of the chloride channel protein, which can malfunction in a variety of ways, each with specific treatment required. Mader, Sylvia S. Human Biology. McGraw Hill Publishing, Burr Ridge, IL. 2004. Van De Graaff, Kent M. Human Anatomy. McGraw Hill Publishing, Burr Ridge, IL. 2002. Department of Environmental Biology, University of Adelaide, Adelaide, South Australia

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Which organ in the body stores excess sugar as glycogen?

The Liver & Blood Sugar :: Diabetes Education Online Diabetes Education Online « Controlling Blood Sugar During a meal, your liver stores sugar for later. When you’re not eating, the liver supplies sugar by turning glycogen into glucose in a process called glycogenolysis. The liver both stores and produces sugar… The liver acts as the body’s glucose (or fuel) reservoir, and helps to keep your circulating blood sugar levels and other body fuels steady and constant. The liver both stores and manufactures glucose depending upon the body’s need. The need to store or release glucose is primarily signaled by the hormones insulin and glucagon . During a meal, your liver will store sugar, or glucose, as glycogen for a later time when your body needs it. The high levels of insulin and suppressed levels of glucagon during a meal promote the storage of glucose as glycogen. The liver makes sugar when you need it…. When you’re not eating – especially overnight or between meals, the body has to make its own sugar. The liver supplies sugar or glucose by turning glycogen into glucose in a process called glycogenolysis. The liver also can manufacture necessary sugar or glucose by harvesting amino acids, waste products and fat byproducts. This process is called gluconeogenesis. The liver also makes another fuel, ketones, when sugar is in short supply…. When your body’s glycogen storage is running low, the body starts to conserve the sugar supplies for the organs that always require sugar. These include: the brain, red blood cells and parts of the kidney. To supplement the limited sugar supply, the liver makes alternative fuels called ketones from fats. This process is called ketogenesis. The hormone signal for ketogenesis to begin is a low level of insulin. Ketones are burned as fuel by muscle and other body organs. And the sugar is saved for the organs that need it. The terms “gluconeogenesis, glycogenolysis and ketogenesis” may seem like complicated concepts or words on a biology test. Take a moment to review the definitions and illustrations above. When you have diabetes, these processes can be thrown off balance, and if you fully understand what is happening, you can take steps to fix the problem. Gluconeogenesis? Glycogenolysis? Ketogenesis? What are they? You need to know. Self-assessment Quiz Self assessment quizzes are available for topics covered in this website. To find out how much you have learned about  Facts about Diabetes, take our self assessment quiz when you have completed this section.  The quiz is multiple choice. Please choose the single best answer to each question. At the end of the quiz, your score will display. If your score is over 70% correct, you are doing very well. If your score is less than 70%, you can return to this section and review the information.  

Liver

What name is given to the small bones which form the spinal column?

How Our Bodies Turn Food Into Energy Classes & Events How Our Bodies Turn Food Into Energy All parts of the body (muscles, brain, heart, and liver) need energy to work. This energy comes from the food we eat. Our bodies digest the food we eat by mixing it with fluids (acids and enzymes) in the stomach. When the stomach digests food, the carbohydrate (sugars and starches) in the food breaks down into another type of sugar, called glucose. The stomach and small intestines absorb the glucose and then release it into the bloodstream. Once in the bloodstream, glucose can be used immediately for energy or stored in our bodies, to be used later. However, our bodies need insulin in order to use or store glucose for energy. Without insulin, glucose stays in the bloodstream, keeping blood sugar levels high. How the Body Makes Insulin Insulin is a hormone made by beta cells in the pancreas. Beta cells are very sensitive to the amount of glucose in the bloodstream. Normally beta cells check the blood's glucose level every few seconds and sense when they need to speed up or slow down the amount of insulin they're making and releasing. When someone eats something high in carbohydrates, like a piece of bread, the glucose level in the blood rises and the beta cells trigger the pancreas to release more insulin into the bloodstream. See Illustration: How Insulin Works Insulin Opens Cell Doors When insulin is released from the pancreas, it travels through the bloodstream to the body's cells and tells the cell doors to open up to let the glucose in. Once inside, the cells convert glucose into energy to use right then or store it to use later. As glucose moves from the bloodstream into the cells, blood sugar levels start to drop. The beta cells in the pancreas can tell this is happening, so they slow down the amount of insulin they're making. At the same time, the pancreas slows down the amount of insulin that it's releasing into the bloodstream. When this happens, the amount of glucose going into the cells also slows down. Balancing Insulin and Blood Sugar for Energy The rise and fall in insulin and blood sugar happens many times during the day and night. The amount of glucose and insulin in our bloodstream depends on when we eat and how much. When the body is working as it should, it can keep blood sugar at a normal level, which is between 70 and 120 milligrams per deciliter. However, even in people without diabetes, blood sugar levels can go up as high as 180 during or right after a meal. Within two hours after eating, blood sugar levels should drop to under 140. After several hours without eating, blood sugar can drop as low as 70. Using glucose for energy and keeping it balanced with just the right amount of insulin — not too much and not too little — is the way our bodies maintain the energy needed to stay alive, work, play, and function even as we sleep. Insulin Helps Our Bodies Store Extra Glucose Insulin helps our cells convert glucose into energy, and it helps our bodies store extra glucose for use later. For example, if you eat a large meal and your body doesn't need that much glucose right away, insulin will help your body store it to convert to energy later. Insulin does this by turning the extra food into larger packages of glucose called glycogen. Glycogen is stored in the liver and muscles. Insulin also helps our bodies store fat and protein. Almost all body cells need protein to work and grow. The body needs fat to protect nerves and make several important hormones. Fat can also be used by the body as an energy source. How Diabetes Changes the Way This Works With diabetes, the body has stopped making insulin, has slowed down the amount of insulin it's making, or is no longer able to use its own insulin very well. When this happens, it can lead to several things. For example, glucose cannot enter the cells where it's needed, so the amount of glucose in the bloodstream continues to rise. This is called hyperglycemia (high blood sugar). When blood sugar levels reach 180 or higher, the kidneys try to get rid of the extra sugar through the urine. This makes a person urinate more than usual. It also makes a person feel thirstier because of the water he or she is losing by urinating so much. When a person loses sugar in the urine, it's the same as losing energy because the sugar isn't available for the cells to use or store. When this happens, a person might feel tired, lose weight, and feel hungry all the time. Other problems caused by high blood sugar include blurry vision and skin infections or injuries that don't heal. Women might have vaginal yeast infections more often. When the body doesn't have enough insulin to help convert sugar into energy, it often starts burning body fat instead. This sounds like it might work well, but burning too much fat for energy produces a byproduct called ketones. High levels of ketones can lead to a condition called diabetic ketoacidosis (DKA), which can be life threatening if not treated quickly. DKA is more common in type 1 diabetes because the body has stopped making insulin. Keep Blood Sugar Levels Under Control For a person with diabetes, the main focus of treatment is to control the amount of glucose in the body so that blood sugar levels stay as close to normal as possible. People with type 1 diabetes need insulin shots as part of their care plan to control their blood sugar levels. Some people with type 2 diabetes can control their blood sugar levels with a healthy diet and exercise. However, many people with type 2 diabetes will need to include diabetes pills, insulin shots, or both in their diabetes care plans. People with either type 1 or type 2 diabetes need to pay close attention to how blood sugar levels change at various times throughout the day in order to keep them as close to normal as possible. When blood sugar levels are close to normal, it means the body is getting the energy it needs to work, play, heal, and stay healthy. Clinical review by David McCulloch, MD Group Health

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Where in the body are the cerebellum, the medulla and the hypothalamus?

Brain – Human Brain Diagrams and Detailed Information Brain Cortices Full Brain Description [Continued from above] . . . in the study of the body; doctors, psychologists, and scientists are continually endeavoring to learn exactly how the many structures of the brain work together intricately to create our powerful human mind. Anatomy of the Brain There are different ways of dividing the brain anatomically into regions. Let’s use a common method and divide the brain into three main regions based on embryonic development: the forebrain, midbrain and hindbrain. Under these divisions: The forebrain (or prosencephalon) is made up of our incredible cerebrum, thalamus, hypothalamus and pineal gland among other features. Neuroanatomists call the cerebral area the telencephalon and use the term diencephalon (or interbrain) to refer to the area where our thalamus, hypothalamus and pineal gland reside. The midbrain (or mesencephalon), located near the very center of the brain between the interbrain and the hindbrain, is composed of a portion of the brainstem. The hindbrain (or rhombencephalon) consists of the remaining brainstem as well as our cerebellum and pons. Neuroanatomists have a word to describe the brainstem sub-region of our hindbrain, calling it the myelencephalon, while they use the word metencephalon in reference to our cerebellum and pons collectively. Before exploring these different regions of the brain, first let’s define the important types of cells and tissues that are the building blocks of them all. Histology Brain cells can be broken into two groups: neurons and neuroglia. Neurons, or nerve cells, are the cells that perform all of the communication and processing within the brain. Sensory neurons entering the brain from the peripheral nervous system deliver information about the condition of the body and its surroundings. Most of the neurons in the brain’s gray matter are interneurons, which are responsible for integrating and processing information delivered to the brain by sensory neurons. Interneurons send signals to motor neurons, which carry signals to muscles and glands. Neuroglia, or glial cells, act as the helper cells of the brain; they support and protect the neurons. In the brain there are four types of glial cells: astrocytes, oligodendrocytes, microglia, and ependymal cells. Astrocytes protect neurons by filtering nutrients out of the blood and preventing chemicals and pathogens from leaving the capillaries of the brain. Oligodendrocytes wrap the axons of neurons in the brain to produce the insulation known as myelin. Myelinated axons transmit nerve signals much faster than unmyelinated axons, so oligodendrocytes accelerate the communication speed of the brain. Microglia act much like white blood cells by attacking and destroying pathogens that invade the brain. Ependymal cells line the capillaries of the choroid plexuses and filter blood plasma to produce cerebrospinal fluid. The tissue of the brain can be broken down into two major classes: gray matter and white matter. Gray matter is made of mostly unmyelinated neurons, most of which are interneurons. The gray matter regions are the areas of nerve connections and processing. White matter is made of mostly myelinated neurons that connect the regions of gray matter to each other and to the rest of the body. Myelinated neurons transmit nerve signals much faster than unmyelinated axons do. The white matter acts as the information highway of the brain to speed the connections between distant parts of the brain and body. Now let’s begin exploring the main structures of our awesome human brain. HINDBRAIN (RHOMBENCEPHALON) Brainstem Connecting the brain to the spinal cord, the brainstem is the most inferior portion of our brain. Many of the most basic survival functions of the brain are controlled by the brainstem. The brainstem is made of three regions: the medulla oblongata, the pons, and the midbrain. A net-like structure of mixed gray and white matter known as the reticular formation is found in all three regions of the brainstem. The reticular formation controls muscle tone in the body and acts as the switch between consciousness and sleep in the brain. The medulla oblongata is a roughly cylindrical mass of nervous tissue that connects to the spinal cord on its inferior border and to the pons on its superior border. The medulla contains mostly white matter that carries nerve signals ascending into the brain and descending into the spinal cord. Within the medulla are several regions of gray matter that process involuntary body functions related to homeostasis. The cardiovascular center of the medulla monitors blood pressure and oxygen levels and regulates heart rate to provide sufficient oxygen supplies to the body’s tissues. The medullary rhythmicity center controls the rate of breathing to provide oxygen to the body. Vomiting, sneezing, coughing, and swallowing reflexes are coordinated in this region of the brain as well. The pons is the region of the brainstem found superior to the medulla oblongata, inferior to the midbrain, and anterior to the cerebellum. Together with the cerebellum, it forms what is called the metencephalon. About an inch long and somewhat larger and wider than the medulla, the pons acts as the bridge for nerve signals traveling to and from the cerebellum and carries signals between the superior regions of the brain and the medulla and spinal cord. Cerebellum The cerebellum is a wrinkled, hemispherical region of the brain located posterior to the brainstem and inferior to the cerebrum. The outer layer of the cerebellum, known as the cerebellar cortex, is made of tightly folded gray matter that provides the processing power of the cerebellum. Deep to the cerebellar cortex is a tree-shaped layer of white matter called the arbor vitae, which means ‘tree of life’. The arbor vitae connects the processing regions of cerebellar cortex to the rest of the brain and body. The cerebellum helps to control motor functions such as balance, posture, and coordination of complex muscle activities. The cerebellum receives sensory inputs from the muscles and joints of the body and uses this information to keep the body balanced and to maintain posture. The cerebellum also controls the timing and finesse of complex motor actions such as walking, writing, and speech. MIDBRAIN (MESENCEPHALON) The midbrain, also known as the mesencephalon, is the most superior region of the brainstem. Found between the pons and the diencephalon, the midbrain can be further subdivided into 2 main regions: the tectum and the cerebral peduncles. The tectum is the posterior region of the midbrain, containing relays for reflexes that involve auditory and visual information. The pupillary reflex (adjustment for light intensity), accommodation reflex (focus on near or far away objects), and startle reflexes are among the many reflexes relayed through this region. Forming the anterior region of the midbrain, the cerebral peduncles contain many nerve tracts and the substantia nigra. Nerve tracts passing through the cerebral peduncles connect regions of the cerebrum and thalamus to the spinal cord and lower regions of the brainstem. The substantia nigra is a region of dark melanin-containing neurons that is involved in the inhibition of movement. Degeneration of the substantia nigra leads to a loss of motor control known as Parkinson’s disease. FOREBRAIN (PROSENCEPHALON) Diencephalon Superior and anterior to the midbrain is the region known as the interbrain, or diencephalon. The thalamus, hypothalamus, and pineal glands make up the major regions of the diencephalon. The thalamus consists of a pair of oval masses of gray matter inferior to the lateral ventricles and surrounding the third ventricle. Sensory neurons entering the brain from the peripheral nervous system form relays with neurons in the thalamus that continue on to the cerebral cortex. In this way the thalamus acts like the switchboard operator of the brain by routing sensory inputs to the correct regions of the cerebral cortex. The thalamus has an important role in learning by routing sensory information into processing and memory centers of the cerebrum. The hypothalamus is a region of the brain located inferior to the thalamus and superior to the pituitary gland. The hypothalamus acts as the brain’s control center for body temperature, hunger, thirst, blood pressure, heart rate, and the production of hormones. In response to changes in the condition of the body detected by sensory receptors, the hypothalamus sends signals to glands, smooth muscles, and the heart to counteract these changes. For example, in response to increases in body temperature, the hypothalamus stimulates the secretion of sweat by sweat glands in the skin. The hypothalamus also sends signals to the cerebral cortex to produce the feelings of hunger and thirst when the body is lacking food or water. These signals stimulate the conscious mind to seek out food or water to correct this situation. The hypothalamus also directly controls the pituitary gland by producing hormones. Some of these hormones, such as oxytocin and antidiuretic hormone, are produced in the hypothalamus and stored in the posterior pituitary gland. Other hormones, such as releasing and inhibiting hormones, are secreted into the blood to stimulate or inhibit hormone production in the anterior pituitary gland. The pineal gland is a small gland located posterior to the thalamus in a sub-region called the epithalamus. The pineal gland produces the hormone melatonin. Light striking the retina of the eyes sends signals to inhibit the function of the pineal gland. In the dark, the pineal gland secretes melatonin, which has a sedative effect on the brain and helps to induce sleep. This function of the pineal gland helps to explain why darkness is sleep-inducing and light tends to disturb sleep. Babies produce large amounts of melatonin, allowing them to sleep as long as 16 hours per day. The pineal gland produces less melatonin as people age, resulting in difficulty sleeping during adulthood. Cerebrum The largest region of the human brain, our cerebrum controls higher brain functions such as language, logic, reasoning, and creativity. The cerebrum surrounds the diencephalon and is located superior to the cerebellum and brainstem. A deep furrow known as the longitudinal fissure runs midsagittally down the center of the cerebrum, dividing the cerebrum into the left and right hemispheres. Each hemisphere can be further divided into 4 lobes: frontal, parietal, temporal, and occipital. The lobes are named for the skull bones that cover them. The surface of the cerebrum is a convoluted layer of gray matter known as the cerebral cortex. Most of the processing of the cerebrum takes place within the cerebral cortex. The bulges of cortex are called gyri (singular: gyrus) while the indentations are called sulci (singular: sulcus). Deep to the cerebral cortex is a layer of cerebral white matter. White matter contains the connections between the regions of the cerebrum as well as between the cerebrum and the rest of the body. A band of white matter called the corpus callosum connects the left and right hemispheres of the cerebrum and allows the hemispheres to communicate with each other. Deep within the cerebral white matter are several regions of gray matter that make up the basal nuclei and the limbic system. The basal nuclei, including the globus pallidus, striatum, and subthalamic nucleus, work together with the substantia nigra of the midbrain to regulate and control muscle movements. Specifically, these regions help to control muscle tone, posture, and subconscious skeletal muscle. The limbic system is another group of deep gray matter regions, including the hippocampus and amygdala, which are involved in memory, survival, and emotions. The limbic system helps the body to react to emergency and highly emotional situations with fast, almost involuntary actions. With so many vital functions under the control of a single incredible organ - and so many important functions carried out in its outer layers - how does our body protect the brain from damage? Our skull clearly offers quite a bit of protection, but what protects the brain from the skull itself? Read on! Meninges Three layers of tissue, collectively known as the meninges, surround and protect the brain and spinal cord. The dura mater forms the leathery, outermost layer of the meninges. Dense irregular connective tissue made of tough collagen fibers gives the dura mater its strength. The dura mater forms a pocket around the brain and spinal cord to hold the cerebrospinal fluid and prevent mechanical damage to the soft nervous tissue. The name dura mater comes from the Latin for “tough mother,” due to its protective nature. The arachnoid mater is found lining the inside of the dura mater. Much thinner and more delicate than the dura mater, it contains many thin fibers that connect the dura mater and pia mater. The name arachnoid mater comes from the Latin for “spider-like mother”, as its fibers resemble a spider web. Beneath the arachnoid mater is a fluid-filled region known as the subarachnoid space. As the innermost of the meningeal layers, the pia mater rests directly on the surface of the brain and spinal cord. The pia mater’s many blood vessels provide nutrients and oxygen to the nervous tissue of the brain. The pia mater also helps to regulate the flow of materials from the bloodstream and cerebrospinal fluid into nervous tissue. Cerebrospinal Fluid Cerebrospinal fluid (CSF) – a clear fluid that surrounds the brain and spinal cord – provides many important functions to the central nervous system. Rather than being firmly anchored to their surrounding bones, the brain and spinal cord float within the CSF. CSF fills the subarachnoid space and exerts pressure on the outside of the brain and spinal cord. The pressure of the CSF acts as a stabilizer and shock absorber for the brain and spinal cord as they float within the hollow spaces of the skull and vertebrae. Inside of the brain, small CSF-filled cavities called ventricles expand under the pressure of CSF to lift and inflate the soft brain tissue. Cerebrospinal fluid is produced in the brain by capillaries lined with ependymal cells known as choroid plexuses. Blood plasma passing through the capillaries is filtered by the ependymal cells and released into the subarachnoid space as CSF. The CSF contains glucose, oxygen, and ions, which it helps to distribute throughout the nervous tissue. CSF also transports waste products away from nervous tissues. After circulating around the brain and spinal cord, CSF enters small structures known as arachnoid villi where it is reabsorbed into the bloodstream. Arachnoid villi are finger-like extensions of the arachnoid mater that pass through the dura mater and into the superior sagittal sinus. The superior sagittal sinus is a vein that runs through the longitudinal fissure of the brain and carries blood and cerebrospinal fluid from the brain back to the heart. Physiology of the Brain Metabolism Despite weighing only about 3 pounds, the brain consumes as much as 20% of the oxygen and glucose taken in by the body. Nervous tissue in the brain has a very high metabolic rate due to the sheer number of decisions and processes taking place within the brain at any given time. Large volumes of blood must be constantly delivered to the brain in order to maintain proper brain function. Any interruption in the delivery of blood to the brain leads very quickly to dizziness, disorientation, and eventually unconsciousness. Sensory The brain receives information about the body’s condition and surroundings from all of the sensory receptors in the body. All of this information is fed into sensory areas of the brain, which put this information together to create a perception of the body’s internal and external conditions. Some of this sensory information is autonomic sensory information that tells the brain subconsciously about the condition of the body. Body temperature, heart rate, and blood pressure are all autonomic senses that the body receives. Other information is somatic sensory information that the brain is consciously aware of. Touch, sight, sound, and hearing are all examples of somatic senses. Motor Control Our brain directly controls almost all movement in the body. A region of the cerebral cortex known as the motor area sends signals to the skeletal muscles to produce all voluntary movements. The basal nuclei of the cerebrum and gray matter in the brainstem help to control these movements subconsciously and prevent extraneous motions that are undesired. The cerebellum helps with the timing and coordination of these movements during complex motions. Finally, smooth muscle tissue, cardiac muscle tissue, and glands are stimulated by motor outputs of the autonomic regions of the brain. Processing Once sensory information has entered the brain, the association areas of the brain go to work processing and analyzing this information. Sensory information is combined, evaluated, and compared to prior experiences, providing the brain with an accurate picture of its conditions. The association areas also work to develop plans of action that are sent to the brain’s motor regions in order to produce a change in the body through muscles or glands. Association areas also work to create our thoughts, plans, and personality. Learning and Memory The brain needs to store many different types of information that it receives from the senses and that it develops through thinking in the association areas. Information in the brain is stored in a few different ways depending on its source and how long it is needed. Our brain maintains short-term memory to keep track of the tasks in which the brain is currently engaged. Short-term memory is believed to consist of a group of neurons that stimulate each other in a loop to keep data in the brain’s memory. New information replaces the old information in short-term memory within a few seconds or minutes, unless the information gets moved to long-term memory. Long-term memory is stored in the brain by the hippocampus. The hippocampus transfers information from short-term memory to memory-storage regions of the brain, particularly in the cerebral cortex of the temporal lobes. Memory related to motor skills (known as procedural memory) is stored by the cerebellum and basal nuclei. Homeostasis The brain acts as the body’s control center by maintaining the homeostasis of many diverse functions such as breathing, heart rate, body temperature, and hunger. The brainstem and the hypothalamus are the brain structures most concerned with homeostasis. In the brainstem, the medulla oblongata contains the cardiovascular center that monitors the levels of dissolved carbon dioxide and oxygen in the blood, along with blood pressure. The cardiovascular center adjusts the heart rate and blood vessel dilation to maintain healthy levels of dissolved gases in the blood and to maintain a healthy blood pressure. The medullary rhythmicity center of the medulla monitors oxygen and carbon dioxide levels in the blood and adjusts the rate of breathing to keep these levels in balance. The hypothalamus controls the homeostasis of body temperature, blood pressure, sleep, thirst, and hunger. Many autonomic sensory receptors for temperature, pressure, and chemicals feed into the hypothalamus. The hypothalamus processes the sensory information that it receives and sends the output to autonomic effectors in the body such as sweat glands, the heart, and the kidneys. Sleep While sleep may seem to be a time of rest for the brain, this organ is actually extremely active during sleep. The hypothalamus maintains the body’s 24 hour biological clock, known as the circadian clock. When the circadian clock indicates that the time for sleep has arrived, it sends signals to the reticular activating system of the brainstem to reduce its stimulation of the cerebral cortex. Reduction in the stimulation of the cerebral cortex leads to a sense of sleepiness and eventually leads to sleep. In a state of sleep, the brain stops maintaining consciousness, reduces some of its sensitivity to sensory input, relaxes skeletal muscles, and completes many administrative functions. These administrative functions include the consolidation and storage of memory, dreaming, and development of nervous tissue. There are two main stages of sleep: rapid eye movement (REM) and non-rapid eye movement (NREM). During REM sleep, the body becomes paralyzed while the eyes move back and forth quickly. Dreaming is common during REM sleep and it is believed that some memories are stored during this phase. NREM sleep is a period of slow eye movement or no eye movement, culminating in a deep sleep of low brain electrical activity. Dreaming during NREM sleep is rare, but memories are still processed and stored during this time. Reflexes A reflex is a fast, involuntary reaction to a form of internal or external stimulus. Many reflexes in the body are integrated in the brain, including the pupillary light reflex, coughing, and sneezing. Many reflexes protect the body from harm. For instance, coughing and sneezing clear the airways of the lungs. Other reflexes help the body respond to stimuli, such as adjusting the pupils to bright or dim light. All reflexes happen quickly by bypassing the control centers of the cerebral cortex and integrating in the lower regions of the brain such as the midbrain or limbic system. Prepared by Tim Taylor, Anatomy and Physiology Instructor  

Brain

What makes up 60-70% of human body weight?

How Alcohol Affects the Brain The Cerebral Cortex and Alcohol | The Limbic System and Alcohol | The Cerebellum and Alcohol | The Hypothalamus, Pituitary Gland and Alcohol | The Medulla and Alcohol The cerebral cortex and alcohol The cerebral cortex processes information from your senses, processes thoughts, initiates the majority of voluntary muscle movements and has some control over lower-order brain centers. In the cerebral cortex, alcohol can: Affect thought processes, leading to potentially poor judgement. Depresses inhibition, leading one to become more talkative and more confident. Blunts the senses and increases the threshold for pain. As the BAC increases, these effects get more pronounced. The limbic system and alcohol The limbic system, which consists of the hippocampus and septal area of the brain, controls memory and emotions. The affect of alcohol on this sytem is that the person may experience some memory loss and may have exaggerated states of emotion. The cerebellum and alcohol The cerebellum coordinates muscle movement. The cerebral cortex initiates the muscular movement by sending a signal through the medulla and spinal cord to the muscles. As the nerve signals pass through the medulla, they are influenced by nerve impulses from the cerebellum, which controls the fine movements, including those necessary for balance. When alcohol affects the cerebellum, muscle movements become uncoordinated. The hypothalamus, pituitary gland and alcohol The hypothalamus controls and influences many automatic functions of the brain (through the medulla), and coordinates hormonal release (through the pituitary gland). Alcohol depresses nerve centers in the hypothalamus that control sexual arousal and performance. With increased alcohol consumption, sexual desire increases - but sexual performance declines. By inhibiting the pituitary secretion of anti-diuretic hormone (ADH), alcohol also affects urine excretion. ADH acts on the kidney to reabsorb water, so when it is inhibitted, ADH levels drop, the kidneys don't reabsorb as much water and the kidneys produce more urine. The medulla and alcohol The medulla (brain stem) influences or controls body functions that occur automatically, such as your heart rate, temperature and breathing. When alcohol affects the medulla, a person will start to feel sleepy. Increased consumption can lead to unconscious. Needless to say, alcohol's effect on the medulla can be fatal if it is excessive. Menu

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What are the very narrow blood vessels which form a network between arteries and veins?

Blood vessels - human anatomy organs Blood vessels Tweet BLOOD VESSELS ANATOMY Blood vessels are responsible for the transportation of blood , made up arteries and veins, they creates pathways for the oxygenated blood to travel to their destination and pathways for the used deoxygenated blood to travel back to the heart or lungs . Capillaries are designed to permit the transfer of gasses within the blood, such as the delivery of oxygen and the return of carbon dioxide. The molecules from the tissues use the oxygenated blood plasma for energy and return the molecules of wastes. Blood vessels form these pathways to reach every living cell within the human body for this gaseous exchange. The network formed by the blood vessels is tubular, extensive, and in many ways fragile to outside influences. BLOOD VESSELS FUNCTIONS As the blood leaves the heart, they are filled with molecules of necessary oxygen, and traverse a passageway of progressively smaller tubular networks known as (in order) arteries, arterioles, and capillaries. The microscopic capillaries are responsible for the conjoining of arterial flow and venous flow. Capillaries create the environment for the actual gaseous exchange. As blood returns to the heart for more oxygen it passes through a tubular network of progressively larger diameter known as (in order) venules and veins. Anastomosis is the convergence arteries. While there are several places throughout the body where this process of anastomosis occurs, this includes the necks of the humerus and femur . Anastomosis occurs in areas that require a constant supply of oxygenated blood. BLOOD VESSELS DIAGRAM Image: Blood Vessels Blood vessels are comprised of three layers which form the tubular network. The outermost layer is comprised of connective tissue. This layer is known as either tunica externa or advetitia. The middle layer is known as tunica media and is comprised of thin muscular tissue. Throughout this stratum there are diverse amounts of elastic fibers. The inner most layer is a combination of simple squamous epithelium and elastin. The layer of squamous epithelium is termed as the endothelium. All blood vessels have this inner layer as their inner lining. BLOOD VESSELS STRUCTURE The structure of a capillary is a bit different. They have a basement membrane for support and have only a endothelium layer. Arteries and veins are nearly the same, with the exception of a few vital differences in their structure. The arteries are responsible for the transport of blood away from the heart while veins are responsible for the transport of blood back to the heart. An artery that is compared with the same sized vein is going to have more muscle in their structure. Cross section comparisons show that arteries are more circular than veins. Veins generally do not fill to capacity and therefore have a more relaxed shape. Veins have the capability to expand when filled with additional blood and make up the body’s venous reservoirs. Arteries are also devoid of valves , which veins are equipped with in their structure. ARTERIES In order for the arteries to expand when the heart fills them with blood and retract when there is absence of blood, the arteries have layers of elastic fibers in between their layers of smooth muscle in the tunica media section. The action of expanding and contracting helps create a more even and less volatile rhythmic pattern of alternating systole and diastole action in the smaller arteries and arterioles. The smaller the artery the less elastic fiber is built into their layers of muscle. This creates an even diameter in the smaller arteries. Larger arteries are designed to expand and contract with the rhythm set forth by the heart. ARTERIES FUNCTIONS The small muscular arteries are more rigid, thus they create more resistance through the circulatory system than veins or larger arteries. These small arteries have very narrow lumina, which is also the case with the small arterioles. The smallest of the arteries branch off to form the arterioles. Any artery that is less than 100 micrometers in diameter will create the arterioles which range between 20 and 30 micrometers in diameter. ARTERIES DIAGRAM Image: Arteries Most often the blood which pulses through the arterioles will then pass through the capillaries for the gaseous exchange. In rare instances, the blood which is pulsating through the arterioles will pass through channels known as metarterioles. This allows the formation of vascular shunts that permit blood to pass directly into the venules. The smallest members of the tubular network are the capillaries, which measure about 7 to 10 micrometers in diameter. The tiniest of the blood vessels serve as functional nits within the circulatory system by permitting the gaseous exchanges to occur across their walls. The capillary walls provide the necessary environment for the exchange of oxygen and carbon dioxide as well as nutrients and wastes between the blood and the body’s tissue. CAPILLARIES Capillaries The human body contains a highly extensive and intricate network of blood vessels which deliver oxygenated blood to the body’s more than 40 billion capillaries. The capillaries are the exchange site for gases, wastes, and nutrients that allow the body’s tissue to function properly. Without this exchange, the tissues of the body would die. The capillary system is so extensive that there isn’t a single cell much more than a fraction of a millimeter from a capillary site. Over 1,000 square miles of systematic networking of capillaries covers the internal network that nature has designed. Throughout this extensive mileage blood and interstitial fluid creates the necessary functions for each cell’s survival. CAPILLARIES STRUCTURE Capillaries only contain a maximum of about 250 milliliters of blood which brings the total blood volume to only a mere 5,000 milliliters inside the walls of the capillaries. The lumina of the veins contains the majority of the body’s blood. The specific amount of blood processing at any given moment in controlled by pre-capillary sphincter muscles. These highly specialized muscles permit only at most 10% of the capillary bed they control to remain open during a period of rest. These muscles also control the variation between capillary beds. The capillary bed for the skeletal muscles may differ from the amount of blood permitted into a capillary bed that distributes blood to a vital organ. When the pre-capillary sphincter muscles control a capillary bed for an internal organ, the blood flow is determined by the sphincter muscles as well as the amount of blood flow resistance within the organ’s arteries and arterioles. While arteries and veins are created by a complex system of layers, capillaries in turn are created by a single layer of cells. This is the endothelium layer, or the simple squamous epithelium layer. The exchange of gases, wastes, and nutrients can only happen in the capillaries because they lack smooth muscle and connective tissue. Otherwise the interstitial fluid and the blood would not be able to pass the necessary molecules through the walls of the capillaries. CAPILLARIES DIAGRAM Image: Capillaries The various distinguishing features of the various types of capillaries make them identifiable. The variation of the endothelial lining may be either continuous, discontinuous, or fenestrated. The capillaries with continuously linings are conjoined firmly together with the epithelial cells that they are flanking. The muscles, lungs, central nervous system and the body’s adipose tissue all contain continuous capillaries. The capillaries within the central nervous system require the capillaries to be continuous and devoid of an intercellular channel, as without the intercellular channels the body is able to enforce the design of the blood-brain barrier. CAPILLARIES STRUCTURE However, other continuous capillaries that reach other organs have these intercellular channels. This is how the various molecules (excluding protein) pass between the blood and the interstitial fluid as well as the body’s circulatory system. While there are still unkowns regarding the human body, studies have confirmed the notion of intercellular channels permitting the exchanges of gases via the study of the endothelial cells. Studies indicate that the endothelial cells have present the pinocytotic cells, which leads researchers to believe intercellular transport happens across the walls of the capillaries. This is the only obvious transport function of molecules within the central nervous system and is likely to account, or at least contribute to, the intense selective operations of the blood-brain barrier. The kidneys , intestines, and the endocrine glands all contain fenestrated capillaries. The large intercellular pores in conjunction with the mucoprotein layer suggest this acts in a diaphragm function for the transport of nutrients and waste gasses. The bone marrow, the liver , and the spleen all have discontinuous capillaries. These organs all have space that has the appearance of cavities due the vast voids between the endothelial cells. VEINS Veins After the exchange of gasses and wastes the occurs when blood enters the capillaries, the by-products must be removed from the blood which means the blood must return through the body and back to the heart. The veins are responsible for the transportation of blood back to the heart. The microscopic vessels which begin the blood’s trek back to the heart are called venules. The veins begin to enlarge incrementally in size as the blood gets closer to its destination. Considering that average arterial pressure is about 100 mmHg, veins carry a much lower pressure, averaging 2mmHg. The pressure in the veins and arteries represent the force applied to the side of the vessel wall indicating hydrostatic pressure. VEINS DIAGRAM Image: Veins The pressure within the veins is insufficient for unassisted return of the blood to the heart. This is especially true of the lower extremities. For the necessary assistance required for veins to be able return the blood to the heart, the veins pass by muscle groups which encourage a gentle massaging motion which increases the blood flow. Venous valves ensure that this massaging motion does not provide excessive blood flow into the heart. This assistance provided by the skeletal muscles has been termed skeletal muscle pumps. The skeletal muscle pump contributes significantly to the rate the blood is returned to the heart via the veins. When the body is at rest for a long period of time, such as recovering from significant illness, blood is permitted to accumulate in the veins due to the inactivity of the skeletal muscle pumps. The accumulation of blood can cause protuberances within the veins. The more active the human body becomes the faster the rate of return of venous blood.

Capillary

What is the ring of bones at the hip called?

The Cardiovascular System: Blood Vessels The Cardiovascular System: Blood Vessels Part 1: Overview of Blood Vessel Structure and Function Structure of Blood Vessel Walls The walls of all blood vessels except the smallest consist of three layers: the tunica intima, tunica media, and tunica externa. The tunica intima reduces friction between the vessel walls and blood; the tunica media controls vasoconstriction and vasodilation of the vessel; and the tunica externa protects, reinforces, and anchors the vessel to surrounding structures.   Arterial System   Elastic, or conducting, arteries contain large amounts of elastin, which enables these vessels to withstand and smooth out pressure fluctuations due to heart action. Muscular, or distributing, arteries deliver blood to specific body organs, and have the greatest proportion of tunica media of all vessels, making them more active in vasoconstriction. Arterioles are the smallest arteries and regulate blood flow into capillary beds through vasoconstriction and vasodilation. Capillaries are the smallest vessels and allow for exchange of substances between the blood and interstitial fluid. Continuous capillaries are most common and allow passage of fluids and small solutes. Fenestrated capillaries are more permeable to fluids and solutes than continuous capillaries. Sinusoidal capillaries are leaky capillaries that allow large molecules to pass between the blood and surrounding tissues.   Capillary beds are microcirculatory networks consisting of a vascular shunt and true capillaries, which function as the exchange vessels. A cuff of smooth muscle, called a precapillary sphincter, surrounds each capillary at the metarteriole and acts as a valve to regulate blood flow into the capillary.   Venous System Venules are formed where capillaries converge and allow fluid and white blood cells to move easily between the blood and tissues. Venules join to form veins, which are relatively thin-walled vessels with large lumens containing about 65% of the total blood volume. Vascular anastomoses form where vascular channels unite, allowing blood to be supplied to and drained from an area even if one channel is blocked . Part 2: Physiology of Circulation Introduction to Blood Flow, Blood Pressure, and Resistance Blood flow is the volume of blood flowing through a vessel, organ, or the entire circulation in a given period and may be expressed as ml/min (blood flow of the entire circulation is equal to cardiac output). Blood pressure is the force per unit area exerted by the blood against a vessel wall and is expressed in millimeters of mercury (mm Hg). Resistance is a measure of the friction between blood and the vessel wall, and arises from three sources: blood viscosity, blood vessel length, and blood vessel diameter.  The variable with the greatest effect on resistance is the diameter (or radius, 1/2 the diameter) of a particular vessel - resistance drops exponentially as the radius increases. TPR is total peripheral resistance - resistance throughout the entire systemic circulation. Relationship Between Flow, Pressure, and Resistance If blood pressure increases, blood flow increases; if peripheral resistance increases, blood flow decreases. Peripheral resistance is the most important factor influencing local blood flow, because vasoconstriction or vasodilation can dramatically alter local resistance while systemic blood pressure remains unchanged (due to homeostatic mechanisms that maintain systemic BP at a constant value, see below). Systemic Blood Pressure The pumping action of the heart generates blood flow; pressure results when blood flow is opposed by resistance. Systemic blood pressure is highest in the aorta, and declines throughout the pathway until it reaches 0 mm Hg in the right atrium. Arterial blood pressure reflects how much the arteries close to the heart can be stretched (compliance, or distensibility), and the volume forced into them at a given time. When the left ventricle contracts, blood is forced into the aorta, producing a peak in pressure called systolic pressure (120 mm Hg). Diastolic pressure occurs when blood is prevented from flowing back into the ventricles by the closed semilunar valve, and the aorta recoils (70–80 mm Hg). The difference between diastolic and systolic pressure is called the pulse presssure. The mean arterial pressure (MAP) represents the pressure that propels blood to the tissues. Capillary blood pressure is low, ranging from 40–20 mm Hg, which protects the capillaries from rupture, but is still adequate to ensure exchange between blood and tissues.   Venous blood pressure changes very little during the cardiac cycle, and is low, reflecting cumulative effects of peripheral resistance (17 mm Hg in venules dropping to almost 0 mm Hg at the termini of the venae cavae). Venous return is aided by both structural modifications and functional adaptations. Structural Smooth muscle layer under sympathetic control   Maintaining Blood Pressure Blood pressure varies with changes in blood volume, TPR, and cardiac output, which are determined primarily by venous return and neural and hormonal controls. Short-term mechanisms include both (1) neural and (2) hormonal controls, which alter blood pressure by changing peripheral resistance and CO. Long-term mechanisms alter blood pressure by using renal controls to alter blood volume.   Short-term Mechanisms Neural controls of peripheral resistance alter blood distribution to (1) meet specific tissue demands and (2) maintain adequate MAP by altering blood vessel diameter. The vasomotor center is a cluster of sympathetic neurons in the medulla, lying close to the cardioacceleratory and cardioinhibitory centers, that controls changes in the diameter of blood vessels. It constantly sends impulses to vascular smooth muscle to maintain a state of partial contraction (remember "tone"?) Most neural controls work through reflex arcs that send information on stretch to effectors (muscle) that respond accordingly. Chemoreceptors and input from higher brain centers can also influence neural controls. Baroreceptors If mean arterial pressure rises, baroreceptors in the carotid sinus and aortic arch detect stretch and send impulses to the vasomotor center, inhibiting its activity and promoting vasodilation of arterioles and veins. They also stimulate the cardioinhibitory center and inhibit the cardioacceleratory center when stretched, reducing cardiac output. A drop in mean arterial pressure causes vasocontriction and increased cardiac ouput. The carotid sinus reflex protects blood flow to the brain, while the aortic reflex maintains blood pressure throughout the systemic circuit.   Chemoreceptors located near the baroreceptors in the carotid sinus and aortic arch detect a rise in carbon dioxide levels, a drop in oxygen levels, and drops in pH of the blood, and stimulate the cardioacceleratory and vasomotor centers, which increases cardiac output and vasoconstriction. The cortex and hypothalamus can modify arterial pressure by signaling the medullary centers. Hormonal Controls Chemicals, both endocrine and paracrine, influence blood pressure by acting on vascular smooth muscle or the vasomotor center. Norepinephrine and epinephrine promote an increase in cardiac output and generalized vasoconstriction when acting on alpha receptors (will promote vasodilation at beta receptors, which are present in skeletal and cardiac muscle). Atrial natriuretic peptide acts as a vasodilator and an antagonist to aldosterone, resulting in a drop in blood volume. Antidiuretic hormone promotes vasoconstriction and water conservation by the kidneys, resulting in an increase in blood volume. Angiotensin II acts as a vasoconstrictor, as well as promoting the release of aldosterone and antidiuretic hormone. Endothelium-derived factors promote vasoconstriction, and are released in response to low blood flow. Nitric oxide is produced in response to high blood flow or other signaling molecules, and promotes systemic and localized vasodilation. Inflammatory chemicals, such as histamine, prostacyclin, and kinins, are potent vasodilators. Alcohol inhibits antidiuretic hormone release and the vasomotor center, resulting in vasodilation.   Long-Term Mechanisms: Renal Mechanisms The direct renal mechanism counteracts changes in blood pressure or volume by altering blood volume independently of hormones. The direct mechanism works best to counteract an increase in blood pressure Increased blood pressure or volume increases the rate of kidney filtration, causing filtrate to be formed faster than water can be reabsorbed back into circulation. The result is an increased volume of dilute urine and a decrease in blood volume. When faced with a decrease in blood pressure it does nothing to increase blood volume, it just decreases the amount of filtrate formed, increases reabsorption from filtrate to blood, and decreases the amount of water lost in urine. The indirect renal mechanism is the renin-angiotensin mechanism, which counteracts a decline in arterial blood pressure by causing systemic vasoconstriction. Monitoring circulatory efficiency is accomplished by measuring pulse and blood pressure; these values together with respiratory rate and body temperature are called vital signs. A pulse is generated by the alternating stretch and recoil of elastic arteries during each cardiac cycle.   Systemic blood pressure is measured indirectly using the ascultatory method, which relies on the use of a blood pressure cuff to alternately stop and reopen blood flow into the brachial artery of the arm. Alterations in blood pressure may result in hypotension (low blood pressure) or transient or persistent hypertension (high blood pressure). Blood Flow Through Body Tissues: Tissue Perfusion Tissue perfusion is involved in delivery of oxygen and nutrients to, and removal of wastes from, tissue cells; gas exchange in the lungs; absorption of nutrients from the digestive tract; and urine formation in the kidneys.   Velocity of Blood Flow Velocity or speed of blood flow changes as it passes through the systemic circulation; it is fastest in the aorta, and declines in velocity as vessel diameter decreases (and then increases on the venous side as vessel diameter increases again).   Autoregulation: Local Regulation of Blood Flow Autoregulation is the automatic adjustment of blood flow to each tissue in proportion to its needs, and is controlled intrinsically by modifying the diameter of local arterioles.  (Extrinsic influences control MAP.) Metabolic controls of autoregulation are most strongly stimulated by a shortage of oxygen at the tissues. Vasodilators: Endothelins Thromboxane A2 Myogenic control involves the localized response of vascular smooth muscle to passive stretch - reflex contraction when stretched to decrease flow, reflex relaxation when stretch is reduced to vasodilate and increase flow. This maintains a relatively constant flow locally when pressure fluctuates. Long-term autoregulation develops over weeks or months, and involves an increase in the size of existing blood vessels and an increase in the number of vessels in a specific area, a process called angiogenesis.   Blood Flow in Special Areas Blood flow to skeletal muscles varies with level of activity and fiber type. Muscular autoregulation occurs almost entirely in response to decreased oxygen concentrations. Cerebral blood flow is tightly regulated to meet neuronal needs, since neurons cannot tolerate periods of ischemia, and increased blood carbon dioxide causes marked vasodilation. In the skin, local autoregulatory events control oxygen and nutrient delivery to the cells, while neural mechanisms control the body temperature regulation function. Autoregulatory controls of blood flow to the lungs are the opposite of what happens in most tissues: low pulmonary oxygen causes vasoconstriction, while higher oxygen causes vasodilation. Movement of blood through the coronary circulation of the heart is influenced by aortic pressure and the pumping of the ventricles. Blood Flow Through Capillaries and Capillary Dynamics Vasomotion, the slow, intermittent flow of blood through the capillaries, reflects the action of the precapillary sphincters in response to local autoregulatory controls. Capillary exchange of nutrients, gases, and metabolic wastes occurs between the blood and interstitial space through diffusion. Routes: Fluid Movements: Bulk Flow (Starlings Law of the Capillary) Hydrostatic pressure (HP) is the force of a fluid against a membrane. Colloid osmotic pressure (OP), the force opposing hydrostatic pressure, is created by the presence of large, nondiffusible molecules that are prevented from moving through the capillary membrane. Fluids will leave the capillaries if net HP exceeds net OP, but fluids will enter the capillaries if net OP exceeds net HP.   Circulatory shock is any condition in which blood volume is inadequate and cannot circulate normally, resulting in blood flow that cannot meet the needs of a tissue. Hypovolemic shock results from a large-scale loss of blood, and may be characterized by an elevated heart rate and intense vasoconstriction. Vascular shock is characterized by a normal blood volume, but extreme vasodilation, often related to a loss of vasomotor tone, resulting in poor circulation and a rapid drop in blood pressure. Anaphylactic shock is an example of vascular shock Neurogenic shock - failure of autonomic controls Septic shock - bacterial toxins, some increase vascular permeability and lower blood volume and others stimulate vasodilation. Transient vascular shock is due to prolonged exposure to heat, such as while sunbathing, resulting in vasodilation of cutaneous blood vessels. Cardiogenic shock occurs when the heart is too inefficient to sustain normal blood flow, and is usually related to myocardial damage, such as repeated myocardial infarcts.   Part 3: Circulatory Pathways: Blood Vessels of the Body Two distinct pathways travel to and from the heart: pulmonary circulation runs from the heart to the lungs and back to the heart; systemic circulation runs to all parts of the body before returning to the heart. There are some important differences between arteries and veins. There is one terminal systemic artery, the aorta, but two terminal systemic veins: the superior and inferior vena cava. Arteries run deep and are well protected, but veins are both deep, running parallel to the arteries, and superficial, running just beneath the skin. Arterial pathways tend to be clear, but there are often many interconnections in venous pathways, making them difficult to follow. There are at least two areas where venous drainage does not parallel the arterial supply: the dural sinuses draining the brain, and the hepatic portal system draining from the digestive organs to the liver before entering the main systemic circulation. Four paired arteries supply the head and neck (common carotid arteries and three branches from the subclavian arteries; the vertebral arteries, the thyrocervical trunks, and the costocervical trunks. The upper limbs are supplied entirely by arteries arising from the subclavian arteries. The arterial supply to the abdomen arises from the aorta. The internal iliac arteries serve mostly the pelvic region; the external iliacs supply blood to the lower limb and abdominal wall. The venae cavae are the major tributaries of the venous circulation.   Blood drained from the head and neck is collected by three pairs of veins (internal jugular veins, external jugular veins, and the vertebral veins). The deep veins of the upper limbs follow the paths of the companion arteries. Blood draining from the abdominopelvic viscera and abdominal walls is returned to the heart by the inferior vena cava. Most deep veins of the lower limb have the same names as the arteries they accompany. Developmental Aspects of the Blood Vessels The vascular endothelium is formed by mesodermal cells that collect throughout the embryo in blood islands, which give rise to extensions that form rudimentary vascular tubes. By the fourth week of development, the rudimentary heart and vessels are circulating blood. Fetal vascular modifications include shunts to bypass fetal lungs (the foramen ovale and ductus arteriosus), the ductus venosus that bypasses the liver, and the umbilical arteries and veins, which carry blood to and from the placenta. At birth, the fetal shunts and bypasses close and become occluded. Congenital vascular problems are rare, but the incidence of vascular disease increases with age, leading to varicose veins, tingling in fingers and toes, and muscle cramping. Atherosclerosis begins in youth, but rarely causes problems until old age.   Blood pressure changes with age: the arterial pressure of infants is about 90/55, but rises steadily during childhood to an average 120/80, and tends to increase to somewhere around 150/90 in old age. Depending on how you live. It's an average but it's also a choice, so workout, eat right, and don't smoke and old age might look better than "young age".

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What tube connects the kidney to the bladder?

KidneyStones.org Ureter Function The ureter is a thick-walled tube leading from each kidney, which carries urine to the bladder. Urine flows down partly by gravity, but mainly by a wave of contractions, called peristalsis, which pass several times per minute through the muscle layers of the urethral walls. Structure Each ureter is a tubular organ measuring about 25 centimeters (ten to twelve inches) in length beginning at the funnel-shaped renal pelvis. Within the wall of the ureter are three layers. The inner layer, or mucous coat, is continuous with the linings of the renal tubules above and the urinary bladder below. The middle layer, or the muscular coat, is composed of largely smooth muscle fibers. The outer layer, or the fibrous coat, is primarily composed of connective tissue. Each ureter enters the bladder through a tunnel in the bladder wall, which is angled to prevent the urine from running back into the ureter, known as reflux, when the bladder contracts.

Ureter

What is the name of the structural tissue found in the ear, the nose, and in between the vertebral discs?

Kidney, Ureter, and Bladder X-ray | Johns Hopkins Medicine Health Library Kidney, Ureter, and Bladder X-ray See related health (KUB [Kidneys, Ureters, Bladder], KUB X-ray, Flat Plate of the Abdomen X-ray) Procedure overview What is a kidneys, ureter, and bladder X-ray? A kidney, ureter, and bladder (KUB) X-ray may be performed to assess the abdominal area for causes of abdominal pain, or to assess the organs and structures of the urinary and/or gastrointestinal (GI) system. A KUB X-ray may be the first diagnostic procedure used to assess the urinary system. X-rays use invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs on film. X-rays are made by using external radiation to produce images of the body, its organs, and other internal structures for diagnostic purposes. X-rays pass through body tissues onto specially treated plates (similar to camera film) and a "negative" type picture is made (the more solid a structure is, the whiter it appears on the film). Digital films and digital media are more commonly used now than the film media. How does the urinary system work? Click Image to Enlarge The body takes nutrients from food and converts them to energy. After the body has taken the food components that it needs, waste products are left behind in the bowel and in the blood. The urinary system helps the body to eliminate liquid waste in the blood called urea, and keeps chemicals, such as potassium and sodium, and water in balance. Urea is produced when foods containing protein, such as meat, poultry, and certain vegetables, are broken down in the body. Urea is carried in the bloodstream to the kidneys, where it is removed along with water and other wastes in the form of urine. Urinary system parts and their functions: Two kidneys. This pair of purplish-brown organs is located below the ribs toward the middle of the back. Their function is to: remove liquid waste from the blood in the form of urine keep a stable balance of salts and other substances in the blood produce erythropoietin, a hormone that aids the formation of red blood cells regulate blood pressure The kidneys remove urea from the blood through tiny filtering units called nephrons. Each nephron consists of a ball formed of small blood capillaries, called a glomerulus, and a small tube called a renal tubule. Urea, together with water and other waste substances, forms the urine as it passes through the nephrons and down the renal tubules of the kidney. Two ureters. These narrow tubes carry urine from the kidneys to the bladder. Muscles in the ureter walls continually tighten and relax forcing urine downward, away from the kidneys. If urine backs up, or is allowed to stand still, a kidney infection can develop. About every 10 to 15 seconds, small amounts of urine are emptied into the bladder from the ureters. Bladder. This triangle-shaped, hollow organ located in the pelvis. It is held in place by ligaments that are attached to other organs and the pelvic bones. The bladder's walls relax and expand to store urine, and contract and flatten to empty urine through the urethra. The typical healthy adult bladder can store up to two cups of urine for two to five hours. Two sphincter muscles. These circular muscles help keep urine from leaking by closing tightly like a rubber band around the opening of the bladder. Nerves in the bladder. The nerves alert a person when it is time to urinate, or empty the bladder. Urethra. This tube allows urine to pass outside the body. The brain signals the bladder muscles to tighten, which squeezes urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra. When all the signals occur in the correct order, normal urination occurs. Facts about urine: Adults pass about a quart and a half of urine each day, depending on the fluids and foods consumed. The volume of urine formed at night is about half that formed in the daytime. Normal urine is sterile. It contains fluids, salts and waste products, but it is free of bacteria, viruses, and fungi. The tissues of the bladder are isolated from urine and toxic substances by a coating that discourages bacteria from attaching and growing on the bladder wall. Reasons for the procedure A KUB X-ray may be performed to help diagnose the cause of abdominal pain, such as masses, perforations, or obstruction. A KUB X-ray may be taken to evaluate the urinary tract before other diagnostic procedures are performed. Basic information regarding the size, shape, and position of the kidneys, ureters, and bladder may be obtained with a KUB X-ray. The presence of calcifications ( kidney stones ) in the kidneys or ureters may be noted. There may be other reasons for your doctor to recommend a KUB X-ray. Risks of the procedure You may want to ask your doctor about the amount of radiation used during the procedure and the risks related to your particular situation. It is a good idea to keep a record of your past history of radiation exposure, such as previous scans and other types of X-rays, so that you can inform your doctor. Risks associated with radiation exposure may be related to the cumulative number of X-ray examinations and/or treatments over a long period of time. Notify your health care provider if you are pregnant or suspect that you may be pregnant. Radiation exposure during pregnancy may lead to birth defects. There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure. Certain factors or conditions may interfere with the accuracy of a KUB X-ray. These factors include, but are not limited to, the following: Recent barium X-rays of the abdomen Gas , feces, or foreign body in the intestine Uterine or ovarian masses, such as calcified fibromas of the uterus or ovarian lesions Before the procedure Your doctor will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure. Generally, no prior preparation, such as fasting or sedation, is required. Notify the radiologic technologist if you are pregnant or suspect you may be pregnant. Notify your doctor and radiologic technologist if you have taken a medication that contains bismuth, such as Pepto-Bismol, in the past four days. Medications that contain bismuth may interfere with testing procedures. Based on your medical condition, your doctor may request other specific preparation. During the procedure A KUB X-ray may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your doctor's practices. Generally, a KUB X-ray follows this process: You will be asked to remove any clothing, jewelry, or other objects that might interfere with the procedure. If you are asked to remove clothing, you will be given a gown to wear. You will be positioned in a manner that carefully places the part of the abdomen that is to be X-rayed between the X-ray machine and a cassette containing the X-ray film or digital media. You may be asked to stand erect, to lie flat on a table, or to lie on your side on a table, depending on the X-ray view your doctor has requested. You may have X-rays taken from more than one position. Body parts not being imaged may be covered with a lead apron (shield) to avoid exposure to the X-rays. Once you are positioned, the radiologic technologist will ask you to hold still for a few moments while the X-ray exposure is made. It is extremely important to remain completely still while the exposure is made, as any movement may distort the image and even require another X-ray to be done to obtain a clear image of the body part in question. The X-ray beam will be focused on the area to be photographed. The radiologic technologist will step behind a protective window while the image is taken. While the X-ray procedure itself causes no pain, the manipulation of the body part being examined may cause some discomfort or pain, particularly in the case of a recent injury or invasive procedure, such as surgery. The radiologic technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain. After the procedure Generally, there is no special type of care following a KUB X-ray. However, your doctor may give you additional or alternate instructions after the procedure, depending on your particular situation. Experience Our Care

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Which artery supplies the kidney with blood?

Blood Supply to the Kidneys - Anatomy Pictures and Information Home > Cardiovascular System > Cardiovascular System of the Lower Torso > Blood Supply to the Kidneys Blood Supply to the Kidneys Providing a constant supply of oxygenated blood to the kidneys is one of the most vital functions of the circulatory system. Despite their relatively small size, the kidneys receive about 20% of the heart’s blood output for filtration. The kidneys’ function is dependent on a constant blood supply, so interruptions in the blood flow to the kidneys may result in tissue death and loss of kidney function. Anatomy Move up/down/left/right: Click compass arrows Rotate image: Click and drag in any direction, anywhere in the frame Identify objects: Click on them in the image 2D Interactive 3D Rotate & Zoom Change Anatomical System Kidney Blood Filtration Full Blood Supply to the Kidneys Description [Continued from above] . . . In the abdomen, the renal arteries branch from the abdominal aorta inferior to the superior mesenteric artery and extend laterally toward the kidneys. Just before reaching the kidney, each renal artery divides into five segmental arteries, which provide blood to the various regions of the kidney. Each segmental artery enters the hilus of the kidney and divides into several interlobar arteries, which pass through the renal columns between the renal pyramids and carry blood toward the exterior of the kidney. At the junction between the renal cortex and renal medulla, the interlobar arteries form the arcuate arteries, which turn to follow the contours of the renal pyramids. From the arcuate arteries several branches, known as interlobular arteries, separate at right angles and extend through the renal cortex toward the exterior of the kidney. Each interlobular artery forms several afferent arterioles, which end in a bed of capillaries known as glomeruli where blood is filtered to form urine. Physiology Kidney function is highly dependent upon sufficient blood pressure in the glomeruli. The arteries and arterioles that provide blood flow to the kidneys must maintain sufficient blood flow to keep the tissues of the kidneys alive and also maintain sufficient blood pressure to allow wastes to be separated from the blood. Interruption of the blood flow through one of the segmental arteries or their branches results in kidney infarction, where kidney tissue dies and ceases to function. Interruption of the blood flow to the entire kidney results in kidney failure. While it is possible to survive with only one functional kidney, loss of both kidneys requires dialysis or a kidney transplant to filter wastes from the blood. Prepared by Tim Taylor, Anatomy and Physiology Instructor

Renal artery

How many ventricles are there in the human heart?

Renal Vascular Disease | Johns Hopkins Medicine Health Library << Back to Diseases and Conditions What is renal vascular disease? Renal vascular disease affects the blood flow into and out of the kidneys. It may cause kidney damage, kidney failure, and high blood pressure. Vascular conditions include: Renal artery stenosis (RAS). This is a narrowing or blockage of an artery to the kidneys. It may cause kidney failure and high blood pressure. Smokers have a greater risk of getting RAS. It’s most common in men between the ages of 50 and 70. High cholesterol, diabetes, being overweight, and having a family history of heart disease are also risk factors for RAS. High blood pressure is both a cause and a result of RAS. Renal artery thrombosis. This is a blood clot in an artery that supplies the kidney. It may block blood flow and cause kidney failure. Renal vein thrombosis. This is the formation of a clot in a vein to the kidney. Renal artery aneurysm. This is a bulging, weak area in the wall of an artery to the kidney. Most are small and don’t cause symptoms. Renal artery aneurysms are rare and are often found during tests for other conditions. Atheroembolic renal disease. This occurs when a piece of plaque from a larger artery breaks off and travels through the blood, blocking small renal arteries. This disease is becoming a common cause of kidney problems in the older adults. Renin is a strong hormone that raises blood pressure. Decreased blood flow to the kidney(s) from renal vascular disease may cause too much renin to be made. This can lead to high blood pressure. What causes renal vascular disease? The cause of renal vascular disease will depend on the specific condition involved. The main causes are: Atherosclerosis On-going severe flank pain with spasms at times Soreness over the kidney, between the ribs and the backbone Decreased kidney function      The symptoms of renal vascular disease may look like other medical conditions or problems. Always consult your health care provider for a diagnosis. How is renal vascular disease diagnosed? Your doctor will review your medical history and do a physical exam. Other tests may include: Arteriogram (or angiogram). This is an X-ray image of the blood vessels used to check for aneurysm, narrowing, or blockages. A dye (contrast) is injected through a thin, flexible tube placed in an artery. This dye makes the blood vessels visible on X-ray. Duplex ultrasound. This test is done to check blood flow and the structure of the renal veins and arteries. The term “duplex" refers to the fact that two modes of ultrasound are used. The first takes an image of the renal artery being studied. The second mode checks the blood flow. Renography. This test is used to check the function and structure of the kidneys. It is a type of nuclear radiology procedure. This means that a tiny amount of a radioactive substance is used during the test to help view the kidneys. Magnetic resonance angiography (MRA). This test uses a combination of magnetic resonance imaging (MRI) technology and intravenous (IV) contrast dye to see blood vessels. Contrast dye causes blood vessels to appear solid on the MRI image. This lets the doctor see the blood vessels. What is the treatment for renal vascular disease? Your health care provider will figure out the best treatment based on: How old you are Blood pressure lowering medications other than ACE inhibitors may be used to treat high blood pressure. Medications to lower cholesterol may be prescribed for atherosclerosis. Treatment of related medical conditions such as diabetes. Surgical treatment: Endovascular procedures such as angioplasty (the opening of a renal artery using a balloon or other method) or placement of a stent (a tiny, expandable metal coil placed inside an artery to keep the artery open). Open surgery to bypass the blocked renal artery. Renal artery thrombosis In acute cases, thrombolytic (clot-busting) medication may be infused into the renal artery for several hours to several days to break up the clot. Surgery to remove the clot or bypass the artery may be done in some situations. Renal artery aneurysm Treatment of a renal artery aneurysm depends on symptoms and the size and location of the aneurysm. Some smaller aneurysms may not be treated, but may be watched for growth or problems. Surgery may be used to treat larger, tearing, or growing aneurysms. It may also be used for aneurysms causing lack of blood flow to the kidney and high blood pressure, and aneurysms causing symptoms. Because of the increased risk for rupture (bursting), a renal artery aneurysm in a pregnant woman or a woman of childbearing age will generally be treated with surgery. Atheroembolic renal disease Treatment may include medications to lower cholesterol, blood pressure, and treat other related conditions, such as diabetes. Diet and exercise are urged to lower blood pressure. Avoid foods high in fats and salt. Surgical treatment may include: Endovascular procedures such as angioplasty (the opening of a renal artery using a balloon or other method) or placement of a stent (a tiny, expandable metal coil placed inside an artery to keep the artery open). Open surgery to bypass the blocked renal artery. Renal vein thrombosis Renal vein thrombosis is generally treated with an anticoagulant, which keeps the blood from clotting. They may be given intravenously (IV) for several days, then given by mouth for a few weeks or more. What are the complications of renal vascular disease? In time, renal vascular disease can lead to kidney failure, which may call for dialysis or a kidney transplant. Other complications include: Heart disease 

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What is the scientific name for the tube connecting the mouth with the stomach?

What tube connects the mouth and the stomach? | Reference.com What tube connects the mouth and the stomach? A: Quick Answer The tube that connects the mouth and the stomach is the esophagus, according to Dictionary.com. The esophagus is a muscular passage found in vertebrate and invertebrate animals. It's sometimes referred to as the "gullet." Full Answer WebMD explains that the esophagus is about 8 inches long and is located behind the heart and trachea, or windpipe, and in front of the spine. WebMD notes that the esophagus passes through the diaphragm just prior to entering the stomach. Muscles at the top of the esophagus are controlled consciously and are used during breathing, eating, vomiting, belching and in preventing food from entering the windpipe, according to WebMD. The muscles at the bottom of the esophagus are involuntary muscles, and they prevent acid and stomach contents from traveling back into the esophagus.

Esophagus

Which parts of the body are formed by the bones of the metatarsals and phalanges?

Ear, Nose, and Throat Facts | Johns Hopkins Medicine Health Library Ear, Nose, and Throat Facts See related health The ear is the organ of hearing and balance. The ear consists of: External or outer ear, consisting of: Pinna or auricle. This is the outside part of the ear. External auditory canal or tube. This is the tube that connects the outer ear to the inside or middle ear. Tympanic membrane (also called the eardrum). The tympanic membrane divides the external ear from the middle ear. Middle ear (tympanic cavity), consisting of: Ossicles. These are the 3 small bones that are connected and transmit the sound waves to the inner ear. The bones are called: Malleus Incus Stapes Eustachian tube. A canal that links the middle ear with the back of the nose. The eustachian tube helps to equalize the pressure in the middle ear. Having the same pressure allows for the proper transfer of sound waves. The eustachian tube is lined with mucous, just like the inside of the nose and throat. Inner ear, consisting of: Cochlea. This contains the nerves for hearing. Vestibule. This contains receptors for balance. Semicircular canals. This contains receptors for balance. What is the nose? The nose is the organ of smell and is part of the peripheral nervous system. The nose consists of: External nose. A triangular-shaped projection in the center of the face. Nostrils. These are two chambers divided by the septum. Septum. This is made up primarily of cartilage and bone and covered by mucous membranes. The cartilage also gives shape and support to the outer part of the nose. Nasal passages. Passages that are lined with mucous membranes and tiny hairs (cilia) that help to filter the air. Sinuses. Four pairs of air-filled cavities that are also lined with mucous membranes. What is the throat? The throat is a ring-like muscular tube that acts as the passageway for air, food, and liquid. The throat also helps in forming speech. The throat consists of: Larynx. This houses the vocal cords and is crucial to speech and breathing. The larynx also serves as a passageway to the trachea (windpipe to the lung). Epiglottis. This is located above the larynx and works with the larynx and vocal cords to push the food into the esophagus, therefore keeping food from entering the windpipe. Tonsils and adenoids. These are made up of lymph tissue and are located at the back and sides of the mouth. They protect against infection, but generally have little purpose beyond childhood. Experience Our Care

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What is the fluid that lubricates and cushions the movable joints between the bones?

what is synovial fluid n wat is its rush? What is synovial fluid n wat is its stress? Answers: Synovial fluid is a thick, stringy fluid found contained by the cavities of synovial joint. With its egg-like consistency (synovial comes from Latin for "egg"), synovial fluid reduces friction between the articular cartilage and other tissues contained by joints to lubricate and cushion them during movement. Overview The inner membrane of synovial joint is called the synovial membrane, which secrete synovial fluid into the joint cavity. This fluid forms a sunken layer (approximately 50 micrometres) at the surface of cartilage, but also seep into the articular cartilage filling any unfilled space . The fluid within articular cartilage effectively serves as a synovial fluid reserve. During majority movements, the synovial fluid held within the cartilage is squeezed out routinely (so-called weeping lubrication) to maintain a band of fluid on the cartilage surface. more: http://en.wikipedia.org/wiki/synovial_fl... It is the fluid around closed joints, approaching the knees. It is very momentous to cushion the joint and keep hold of it lubricated and healthy. Joints that aren't roofed, like the spine, don't hold it, but are cushioned differently. Any of the sites below should have the answer you are looking for :-) http://adam.nearly.com/encyclopedia/19698... Synovial fluid is in adjectives of your freely movable joints. Elbow, Knee ,etc. It's rush is that it keeps your joint lubricated so that there is no friction. So not to mess up your bones. Synovial fluid is a viscous colourless fluid that bathe movable joints between the bones of vertebrates. It nourish and lubricates the cartilage at the end of respectively bone. The normal knees joint is surrounded by a membrane (the synovium) which produces a small amount of gooey fluid (synovial fluid). The synovial fluid helps to provide for the cartilage and keep it slippery. Synovial fluid is secreted by a membrane, the synovium, that links movably jointed bones. The same thoughtful of fluid is found in bursae, the membranous sac that buffer some joints, such as surrounded by the shoulder and hip region. Viscid lubricating fluid secreted by the membrane lining joint and tendon sheaths etc synovial common is a type of joint that allows free movements of bones..these joint r lined by a synovial membrane that secrete synovial fluid..Synovial fluid is normally a viscous (thick), straw colored substance that help in free movements of bones inwardly the joints..synovial fluid is tested surrounded by suspected joint pathologies..To gain the fluid for analysis, a sterile needle is inserted into the common space through skin that has be specially cleaned. Once in the pooled, fluid is aspirated through the needle into a sterile syringe.. It is consequently examined microscopically for cells (red and white cells), crystals (in the valise of gout), and bacteria. In assimilation, there may be a chemical analysis, and if infection is a concern, a example will be cultured to see if any bacteria grow. Abnormal cohesive fluid may look cloudy or abnormally gluey. Synovial fluid is a thick, stringy fluid found surrounded by the cavities of synovial joint. With its egg-like consistency (synovial comes from Latin for "egg"), synovial fluid reduces friction between the articular cartilage and other tissues contained by joints to lubricate and cushion them during movement. it is fluid present contained by joint contained by joint cavity.relief in lubrication of unified. synovial fluid is the fluid between your joints it keep the bones from rubbing together synovial fluid s actually fluid ie present surrounded by joints. it help as a lubricating agent for easy movement of joint without injuring the bones. synovial membrane forms the facing of the soft parts that enclose the cavity of a cohesive...the cavity has the synovial fluid it help in th lubrication of the joint.SYNOVITIS is the inflammation of the membrane lining the joint its a substance present between two joints & help in lubrication this is a fluid that s found surrounded by the joints of knees, elbow, etc. its gives the fluidity and flexibility for the movement of joint. inflammation of this leads to arthritis y do u want to know? Related Questions and Answers Ptosis operation results worth it or not? Good question. The results are not always perfect. It depends on the impose of the ptosis, the degree of the ptosis and the skill of the ophthalmologic or plastic surgeon, perhaps other factors. Ideally your personal physician should be capable of refer you to a specialist whose results he has previously witnessed. Or, you can... Food is broken down by tart surrounded by the stomach...? but what happens to this acid when we drink water. does it catch flushed to the intestines? how does the stomach keep producing enough over and over again? The stomach produces acid for as long as we are alive (or as long as the stomach is on form, anyway), through glands in the...

Synovial fluid

What is the oxygen-carrying protein found in the red blood cells of the body?

Immovable joint | Article about immovable joint by The Free Dictionary Immovable joint | Article about immovable joint by The Free Dictionary http://encyclopedia2.thefreedictionary.com/immovable+joint Also found in: Dictionary , Thesaurus , Medical , Legal , Financial , Wikipedia . joint, in anatomy, juncture between two bones. Some joints are immovable, e.g., those that connect the bones of the skull, which are separated merely by short, tough fibers of cartilage. Movable joints are found for the most part in the limbs. Hinge joints provide a forward and backward motion, as at the elbow and knee. Pivot joints permit rotary movement, like the turning of the head from side to side. Ball-and-socket joints, like those at the hip and shoulder, allow the greatest range of movement, as the rounded end of one bone fits into the hollow or socket of another bone, separated by elastic cartilage. Joints can further be classified as fibrous, cartilaginous, and synovial. Collagen fibers connect fibrous joints. Synovial joints ease movement through the use of a lubricating liquid, supplied by the synovial membrane that lines movable joints. In synovial joints, a cushioning sac known as a bursa bursa , closed fibrous sac lined with a smooth membrane, producing a viscous lubricant known as synovial fluid. Bursas are found in regions where muscles or tendons rub against other muscles, tendons, or bones. ..... Click the link for more information.  contains the fluid, which lubricates and nourishes the joint. Those joints which lack synovial fluid are nourished by blood. Holding the joints in place are strong ligaments ligament , strong band of white fibrous connective tissue that joins bones to other bones or to cartilage in the joint areas. The bundles of collagenous fibers that form ligaments tend to be pliable but not elastic. ..... Click the link for more information.  fastened to the bones above and below the joint. Joints are subject to sprains sprain, stretching or wrenching of the ligaments and tendons of a joint, often with rupture of the tissues but without dislocation. Sprains occur most commonly at the ankle, knee, or wrist joints, causing pain, swelling, and difficulty in moving the involved joint. ..... Click the link for more information.  and dislocations, as well as to infections and disorders caused by such diseases as arthritis arthritis, painful inflammation of a joint or joints of the body, usually producing heat and redness. There are many kinds of arthritis. In its various forms, arthritis disables more people than any other chronic disorder. ..... Click the link for more information. . In recent years, the use of artificial joints has become increasingly common, particularly in hip and knee replacement. Many orthopedic surgeons now perform operations of this sort, using metal or plastic replacement joints in order to relieve pain, or to prevent or correct joint deformity. joint, in geology, fracture in rocks along which no appreciable movement has occurred (see fault fault, in geology, fracture in the earth's crust in which the rock on one side of the fracture has measurable movement in relation to the rock on the other side. Faults on other planets and satellites of the solar system also have been recognized. ..... Click the link for more information. ). Nearly vertical, or sheet, joints that result from shrinkage during cooling are commonly found in igneous rocks. Similar joints occur in thick beds of sandstone and gneiss, with the sheets resembling the structure of a sliced onion. The prismatic joints of the Palisades of New Jersey and Devil's Tower, Wyoming, are examples of joints caused by contraction during the cooling of fine-grained igneous rock masses. Deep-seated igneous rocks often have joints approximately parallel to the surface, suggesting that they formed by expansion of the rock mass as overlying rocks were eroded away. Some joints in sedimentary rocks may have formed as the result of contraction during compaction and drying of the sediment. In some cases, jointing of the rock may result from the action of the same forces that cause folds fold, in geology, bent or deformed arrangement of stratified rocks. These rocks may be of sedimentary or volcanic origin. Although stratified rocks are normally deposited on the earth's surface in horizontal layers (see stratification), they are often found inclined or curved ..... Click the link for more information.  and faults. In relatively undisturbed sedimentary rocks, such joints are often in two vertical sets perpendicular to one another. Commonly, streams develop along zones of weakness caused by joints in rocks, and thus the regional pattern of joint orientation often exerts a strong control on the development of drainage patterns. Joint (anatomy) The structural component of an animal skeleton where two or more skeletal elements meet, including the supporting structures within and surrounding it. The relative range of motion between the skeletal elements of a joint depends on the type of material between these elements, the shapes of the contacting surfaces, and the configuration of the supporting structures. In bony skeletal systems, there are three general classes of joints: synarthroses, amphiarthroses, and diarthroses. Synarthroses are joints where bony surfaces are directly connected with fibrous tissue, allowing very little if any motion. Synarthroses may be further classified as sutures, syndesmoses, and gomphoses. Sutures are joined with fibrous tissue, as in the coronal suture where the parietal and frontal bones of the human skull meet. Syndesmoses are connected with ligaments, as are the shafts of the tibia and fibula. The roots of a tooth that are anchored in the jaw bone with fibrous tissue form a gomphosis. Amphiarthroses are joints where bones are directly connected with fibrocartilage or hyaline cartilage and allow only limited motion. An amphiarthrosis joined with fibrocartilage, as found between the two pubic bones of the pelvis, is known as a symphysis; but when hyaline cartilage joins the bones, a synchondrosis is formed, an example being the first sternocostal joint. The greatest range of motion is found in diarthrodial joints, where the articulating surfaces slide and to varying degrees roll against each other. See Ligament The contacting surfaces of the bones of a diarthrodial joint are covered with articular cartilage, an avascular, highly durable hydrated soft tissue that provides shock absorption and lubrication functions to the joint (see illustration). Articular cartilage is composed mainly of water, proteoglycans, and collagen. The joint is surrounded by a fibrous joint capsule lined with synovium, which produces lubricating synovial fluid and nutrients required by the tissues within the joint. Joint motion is provided by the muscles that are attached to the bone with tendons. Strong flexible ligaments connected across the bones stabilize the joint and may constrain its motion. Different ranges of motion result from several basic types of diarthrodial joints: pivot, gliding, hinge, saddle, condyloid, and ball-and-socket. See Collagen Cross section of the human knee showing its major components Joint The space between the stones in masonry or between the bricks in brick work. In concrete work, joints control the shrinkage on large areas and isolate independent elements. angle joint Any joint formed by uniting two members at a corner which results in a change of direction. bevel joint Any joint in which the ends of the two abutting elements are cut at an angle, especially when not forming a right angle. blind joint

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What are the chemicals produced by the endocrine glands to control body functions?

Hormones: the body’s chemical messengers | Visual Dictionary Subscribe Hormones: the body’s chemical messengers The human body secretes and circulates some 50 different hormones. A wide variety of these chemical substances are produced by endocrine cells, most of which are in glands. The hormones then enter the blood system to circulate throughout the body and activate target cells. The endocrine system, tightly linked to the nervous system , controls a large number of the body’s functions: metabolism, homeostasis, growth, sexual activity, and contraction of the smooth and cardiac muscles. The endocrine glands The endocrine system is composed of nine specialized glands (the pituitary, the thyroid, the four parathyroids, the two adrenals and the thymus) and a number of organs capable of producing hormones (including the pancreas , heart , kidneys , ovaries , testicles and intestines). The hypothalamus , which is not a gland but a nerve center, also plays a major role in the synthesis of hormonal factors. The endocrine system The hypothalamus and the pituitary gland: the control centers of the endocrine system Located under the thalamus, the hypothalamus is composed of several nuclei that control the autonomic nervous system and regulate hunger, thirst, body temperature and sleep. The hypothalamus also influences sexual behavior and controls the emotions of anger and fear. Closely linked to the pituitary gland , it acts as a coordinator between the nervous and endocrine systems. Generally considered the master endocrine gland, the pituitary secretes 10 different hormones. Some of these substances then act on the other endocrine glands. Unlike substances produced by the exocrine glands, which flow through ducts, the hormones are released directly into the space that surrounds them by secreting cells. The very high vascularization of endocrine glands enables hormones to spread throughout the blood system via the capillaries. Some of them circulate freely in the blood, while others must attach to carrier proteins to reach the target cells.

Hormone

Where in the human body do you find the alveoli?

A&P Review - The Endocrine System A&P Review MECHANISMS OF HORMONE ACTION A. Endocrine glands secrete chemicals (hormones) into the blood B. Hormones perform general functions of communication and control but a slower, longer-lasting type of control than that provided by nerve impulses C. Cells acted on by hormones are called target organ cells D. Protein hormones (first messengers) bind to receptors on the target cell membrane, triggering second messengers to affect the cell’s activities E. Steroid hormones bind to receptors within the target cell nucleus and influence cell activity by acting on DNA A. Endocrine glands secrete chemicals (hormones) into the blood B. Hormones perform general functions of communication and control but a slower, longer-lasting type of control than that provided by nerve impulses C. Cells acted on by hormones are called target organ cells D. Protein hormones (first messengers) bind to receptors on the target cell membrane, triggering second messengers to affect the cell’s activities E. Steroid hormones bind to receptors within the target cell nucleus and influence cell activity by acting on DNA MECHANISMS OF HORMONE ACTION A. Hormone secretion is controlled by homeostatic feedback B. Negative feedback—mechanisms that reverse the direction of a change in a physiological system C. Positive feedback—(uncommon) mechanisms that amplify physiological changes A. Hormone secretion is controlled by homeostatic feedback B. Negative feedback—mechanisms that reverse the direction of a change in a physiological system C. Positive feedback—(uncommon) mechanisms that amplify physiological changes REGULATION OF HORMONE SECRETION PROSTAGLANDINS A. Prostaglandins (PGs) are powerful substances found in a wide variety of body tissues B. PGs are often produced in a tissue and diffuse only a short distance to act on cells in that tissue C. Several classes of PGs include prostaglandin A (PGA), prostaglandin E (PGE), and prostaglandin F (PGF) D. PGs influence many body functions, including respiration, blood pressure, gastrointestinal secretions, and reproduction A. Prostaglandins (PGs) are powerful substances found in a wide variety of body tissues B. PGs are often produced in a tissue and diffuse only a short distance to act on cells in that tissue C. Several classes of PGs include prostaglandin A (PGA), prostaglandin E (PGE), and prostaglandin F (PGF) D. PGs influence many body functions, including respiration, blood pressure, gastrointestinal secretions, and reproduction PROSTAGLANDINS A. Anterior pituitary gland (adenohypophysis) 1. Names of major hormones a. Thyroid-stimulating hormone (TSH) Functions of major hormones a. TSH—stimulates growth of the thyroid gland; also stimulates it to secrete thyroid hormone b. ACTH—stimulates growth of the adrenal cortex and stimulates it to secrete glucocorticoids (mainly cortisol) c. FSH—initiates growth of ovarian follicles each month in the ovary and stimulates one or more follicles to develop to the stage of maturity and ovulation; FSH also stimulates estrogen secretion by developing follicles; stimulates sperm production in the male d. LH—acts with FSH to stimulate estrogen secretion and follicle growth to maturity; causes ovulation; causes luteinization of the ruptured follicle and stimulates progesterone secretion by corpus luteum; causes interstitial cells in the testes to secrete testosterone in the male e. MSH—causes a rapid increase in the synthesis and spread of melanin (pigment) in the skin f. GH—stimulates growth by accelerating protein anabolism; also accelerates fat catabolism and slows glucose catabolism; by slowing glucose catabolism, tends to increase blood glucose to higher than normal level (hyperglycemia) g. Prolactin or lactogenic hormone—stimulates breast development during pregnancy and secretion of milk after the delivery of the baby B. Posterior pituitary gland (neurohypophysis) 1. Names of hormones b. Oxytocin 2. Functions of hormones a. ADH—accelerates water reabsorption from urine in the kidney tubules into the blood, thereby decreasing urine secretion b. Oxytocin—stimulates the pregnant uterus to contract; may initiate labor; causes glandular cells of the breasts to release milk into ducts A. Anterior pituitary gland (adenohypophysis) 1. Names of major hormones a. Thyroid-stimulating hormone (TSH) b. Adrenocorticotropic hormone (ACTH) c. Follicle-stimulating hormone (FSH) d. Luteinizing hormone (LH) e. Melanocyte-stimulating hormone (MSH) f. Growth hormone (GH) g. Prolactin (lactogenic hormone) Functions of major hormones a. TSH—stimulates growth of the thyroid gland; also stimulates it to secrete thyroid hormone b. ACTH—stimulates growth of the adrenal cortex and stimulates it to secrete glucocorticoids (mainly cortisol) c. FSH—initiates growth of ovarian follicles each month in the ovary and stimulates one or more follicles to develop to the stage of maturity and ovulation; FSH also stimulates estrogen secretion by developing follicles; stimulates sperm production in the male d. LH—acts with FSH to stimulate estrogen secretion and follicle growth to maturity; causes ovulation; causes luteinization of the ruptured follicle and stimulates progesterone secretion by corpus luteum; causes interstitial cells in the testes to secrete testosterone in the male e. MSH—causes a rapid increase in the synthesis and spread of melanin (pigment) in the skin f. GH—stimulates growth by accelerating protein anabolism; also accelerates fat catabolism and slows glucose catabolism; by slowing glucose catabolism, tends to increase blood glucose to higher than normal level (hyperglycemia) g. Prolactin or lactogenic hormone—stimulates breast development during pregnancy and secretion of milk after the delivery of the baby B. Posterior pituitary gland (neurohypophysis) 1. Names of hormones a. Antidiuretic hormone (ADH) b. Oxytocin 2. Functions of hormones a. ADH—accelerates water reabsorption from urine in the kidney tubules into the blood, thereby decreasing urine secretion b. Oxytocin—stimulates the pregnant uterus to contract; may initiate labor; causes glandular cells of the breasts to release milk into ducts PITUITARY GLAND A. Actual production of ADH and oxytocin occurs in the hypothalamus B. After production in the hypothalamus, hormones pass along axons into the pituitary gland C. The secretion and release of posterior pituitary hormones is controlled by nervous stimulation D. The hypothalamus controls many body functions related to homeostasis (temperature, appetite, and thirst) A. Actual production of ADH and oxytocin occurs in the hypothalamus B. After production in the hypothalamus, hormones pass along axons into the pituitary gland C. The secretion and release of posterior pituitary hormones is controlled by nervous stimulation D. The hypothalamus controls many body functions related to homeostasis (temperature, appetite, and thirst) HYPOTHALAMUS 1. Thyroid hormone—thyroxine (T4) and triiodothyronine (T3) 2. Calcitonin B. Functions of hormones 1. Thyroid hormones—accelerate catabolism (increase the body’s metabolic rate) 2. Calcitonin—decreases the blood calcium concentration by inhibiting breakdown of bone, which would release calcium into the blood A. Names of hormones 1. Thyroid hormone—thyroxine (T4) and triiodothyronine (T3) 2. Calcitonin B. Functions of hormones 1. Thyroid hormones—accelerate catabolism (increase the body’s metabolic rate) 2. Calcitonin—decreases the blood calcium concentration by inhibiting breakdown of bone, which would release calcium into the blood THYROID GLAND PARATHYROID GLANDS A. Name of hormone—parathyroid hormone (PTH) B. Function of hormone—increases blood calcium concentration by increasing the breakdown of bone with the release of calcium into the blood A. Name of hormone—parathyroid hormone (PTH) B. Function of hormone—increases blood calcium concentration by increasing the breakdown of bone with the release of calcium into the blood PARATHYROID GLANDS 1. Names of hormones (corticoids) a. Glucocorticoids (GCs)—chiefly cortisol (hydrocortisone) b. Mineralocorticoids (MCs)—chiefly aldosterone c. Sex hormones—small amounts of male hormones (androgens) secreted by adrenal cortex of both sexes 2. Cell layers (zones) a. Outer layer—secretes mineralocorticoids b. Middle layer—secretes glucocorticoids c. Inner layer—secretes sex hormones 3. Mineralocorticoids—increase blood sodium and decrease body potassium concentrations by accelerating kidney tubule reabsorption of sodium and excretion of potassium 4. Functions of glucocorticoids a. Help maintain normal blood glucose concentration by increasing gluconeogenesis—the formation of “new” glucose from amino acids produced by the breakdown of proteins, mainly those in muscle tissue cells; also the conversion to glucose of fatty acids produced by the breakdown of fats stored in adipose tissue cells b. Play an essential part in maintaining normal blood pressure—make it possible for epinephrine and norepinephrine to maintain a normal degree of vasoconstriction, a condition necessary for maintaining normal blood pressure c. Act with epinephrine and norepinephrine to produce an anti-inflammatory effect, to bring about normal recovery from inflammations of various kinds d. Produce anti-immunity, antiallergy effect; bring about a decrease in the number of lymphocytes and plasma cells and therefore a decrease in the amount of antibodies formed e. Secretion of glucocorticoid quickly increases when the body is thrown into a condition of stress; high blood concentration of glucocorticoids, in turn, brings about many other stress responses ( 9-10) B. Adrenal medulla 1. Names of hormones—epinephrine (adrenaline) and norepinephrine 2. Functions of hormones—help the body resist stress by intensifying and prolonging the effects of sympathetic stimulation; increased epinephrine secretion is the first endocrine response to stress A. Adrenal cortex 1. Names of hormones (corticoids) a. Glucocorticoids (GCs)—chiefly cortisol (hydrocortisone) b. Mineralocorticoids (MCs)—chiefly aldosterone c. Sex hormones—small amounts of male hormones (androgens) secreted by adrenal cortex of both sexes 2. Cell layers (zones) a. Outer layer—secretes mineralocorticoids b. Middle layer—secretes glucocorticoids c. Inner layer—secretes sex hormones 3. Mineralocorticoids—increase blood sodium and decrease body potassium concentrations by accelerating kidney tubule reabsorption of sodium and excretion of potassium 4. Functions of glucocorticoids a. Help maintain normal blood glucose concentration by increasing gluconeogenesis—the formation of “new” glucose from amino acids produced by the breakdown of proteins, mainly those in muscle tissue cells; also the conversion to glucose of fatty acids produced by the breakdown of fats stored in adipose tissue cells b. Play an essential part in maintaining normal blood pressure—make it possible for epinephrine and norepinephrine to maintain a normal degree of vasoconstriction, a condition necessary for maintaining normal blood pressure c. Act with epinephrine and norepinephrine to produce an anti-inflammatory effect, to bring about normal recovery from inflammations of various kinds d. Produce anti-immunity, antiallergy effect; bring about a decrease in the number of lymphocytes and plasma cells and therefore a decrease in the amount of antibodies formed e. Secretion of glucocorticoid quickly increases when the body is thrown into a condition of stress; high blood concentration of glucocorticoids, in turn, brings about many other stress responses ( 9-10) B. Adrenal medulla 1. Names of hormones—epinephrine (adrenaline) and norepinephrine 2. Functions of hormones—help the body resist stress by intensifying and prolonging the effects of sympathetic stimulation; increased epinephrine secretion is the first endocrine response to stress ADRENAL GLANDS 1. Glucagon—secreted by alpha cells 2. Insulin—secreted by beta cells B. Functions of hormones 1. Glucagon increases the blood glucose level by accelerating liver glycogenolysis (conversion of glycogen to glucose) 2. Insulin decreases the blood glucose by accelerating the movement of glucose out of the blood into cells, which increases glucose metabolism by cells A. Names of hormones 1. Glucagon—secreted by alpha cells 2. Insulin—secreted by beta cells B. Functions of hormones 1. Glucagon increases the blood glucose level by accelerating liver glycogenolysis (conversion of glycogen to glucose) 2. Insulin decreases the blood glucose by accelerating the movement of glucose out of the blood into cells, which increases glucose metabolism by cells PANCREATIC ISLETS The ovaries contain two structures that secrete hormones—the ovarian follicles and the corpus luteum A. Effects of estrogen (feminizing hormone) 1. Development and maturation of breasts and external genitals 2. Development of adult female body contours 3. Initiation of menstrual cycle The ovaries contain two structures that secrete hormones—the ovarian follicles and the corpus luteum A. Effects of estrogen (feminizing hormone) 1. Development and maturation of breasts and external genitals 2. Development of adult female body contours 3. Initiation of menstrual cycle FEMALE SEX GLANDS The interstitial cells of testes secrete the male hormone testosterone A. Effects of testosterone (masculinizing hormone) 1. Maturation of external genitals 2. Beard growth 3. Voice changes at puberty 4. Development of musculature and body contours typical of the male The interstitial cells of testes secrete the male hormone testosterone A. Effects of testosterone (masculinizing hormone) 1. Maturation of external genitals 2. Beard growth 3. Voice changes at puberty 4. Development of musculature and body contours typical of the male MALE SEX GLANDS THYMUS A. Name of hormone—thymosin B. Function of hormone—plays an important role in the development and function of the body’s immune system A. Name of hormone—thymosin B. Function of hormone—plays an important role in the development and function of the body’s immune system THYMUS A. Name of hormones—chorionic gonadotropins, estrogens, and progesterone B. Functions of hormones—maintain the corpus luteum during pregnancy A. Name of hormones—chorionic gonadotropins, estrogens, and progesterone B. Functions of hormones—maintain the corpus luteum during pregnancy PLACENTA A. A cone-shaped gland near the roof of the third ventricle of the brain 1. Glandular tissue predominates in children and young adults 2. Becomes fibrous and calcified with age B. Called third eye because its influence on secretory activity is related to the amount of light entering the eyes C. Secretes melatonin, which: 1. Inhibits ovarian activity 2. Regulates the body’s internal clock A. A cone-shaped gland near the roof of the third ventricle of the brain 1. Glandular tissue predominates in children and young adults 2. Becomes fibrous and calcified with age B. Called third eye because its influence on secretory activity is related to the amount of light entering the eyes C. Secretes melatonin, which: 1. Inhibits ovarian activity 2. Regulates the body’s internal clock PINEAL GLAND OTHER ENDOCRINE STRUCTURES A. Many organs (for example, the stomach, intestines, and kidney) produce endocrine hormones The following is a list of the primary endocrine glands, their location, and their hormonal secretions. ➢ Pituitary gland—lies deep in the cranial cavity, in the small depression of the sphenoid bone called the sella turcica. Secretions of the anterior lobe include growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, luteinizing hormone, melanocyte-stimulating hormone, and prolactin. Secretions of the posterior lobe include antidiuretic hormone and oxytocin ➢ Thyroid gland—lies in the neck, just below the larynx; secretes thyroxine, triiodothyronine, and calcitonin ➢ Parathyroid glands—four small glands found on the back of the thyroid; secrete parathyroid hormone ➢ Adrenal glands—located over the top of each kidney. The adrenal cortex secretes mineralocorticoids, glucocorticoids, and small amounts of sex hormones. The adrenal medulla secretes epinephrine and norepinephrine ➢ Islets of Langerhans—clumps of cells scattered among pancreatic cells; secrete glucagon and insulin ➢ Sex glands—ovaries of the female located toward the back of the pelvic cavity; secrete estrogen and progesterone. Testes of the male located in the scrotum; secrete testosterone ➢ Thymus—located in the mediastinum; secretes thymosin ➢ Placenta—temporary endocrine gland formed during pregnancy; secretes chorionic gonadotropin ➢ Pineal gland—small, cone-shaped gland that lies near the roof of the third ventricle of the brain; secretes melatonin A. Many organs (for example, the stomach, intestines, and kidney) produce endocrine hormones The following is a list of the primary endocrine glands, their location, and their hormonal secretions. ➢ Pituitary gland—lies deep in the cranial cavity, in the small depression of the sphenoid bone called the sella turcica. Secretions of the anterior lobe include growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, luteinizing hormone, melanocyte-stimulating hormone, and prolactin. Secretions of the posterior lobe include antidiuretic hormone and oxytocin ➢ Thyroid gland—lies in the neck, just below the larynx; secretes thyroxine, triiodothyronine, and calcitonin ➢ Parathyroid glands—four small glands found on the back of the thyroid; secrete parathyroid hormone ➢ Adrenal glands—located over the top of each kidney. The adrenal cortex secretes mineralocorticoids, glucocorticoids, and small amounts of sex hormones. The adrenal medulla secretes epinephrine and norepinephrine ➢ Islets of Langerhans—clumps of cells scattered among pancreatic cells; secrete glucagon and insulin ➢ Sex glands—ovaries of the female located toward the back of the pelvic cavity; secrete estrogen and progesterone. Testes of the male located in the scrotum; secrete testosterone ➢ Thymus—located in the mediastinum; secretes thymosin ➢ Placenta—temporary endocrine gland formed during pregnancy; secretes chorionic gonadotropin ➢ Pineal gland—small, cone-shaped gland that lies near the roof of the third ventricle of the brain; secretes melatonin OTHER ENDOCRINE STRUCTURES

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What name is given to the genetic make-up of an individual?

A genotype is the genetic make up of an individual Pearson - BIO - 1100 View Full Document Name ______Bennett_ ____ Page 2 of 7 Heredity 4. Explain Mendel’s “law” of “independent assortment”. When does it occur during cell division? Mendel’s law of independent assortment states that each pair of factors assorts independently of the other pairs and that all possible combinations of factors can occur in the gametes. (Mader and Windelspecht) This means that the genes from one trait separate independently from the genes of another trait allowing for multiple different outcomes. Independent assortment occurs in meiosis I, specifically in prophase I. 5. Explain Mendel’s “law” of “segregation”. Give an example. Mendel’s law of segregation states that each individual has two factors for each trait and that these factors separate during the formation of gametes. Each gamete then contains only one gene from each pair of genes. Fertilization then gives each new individual two genes for each trait. (Mader and Windelspecht) An example of the law of segregation is shown in the lab when the genes from a tall pea plant are combined with the genes of a dwarf pea plant resulting in the separation of the gametes and allowing for either a tall pea plant or dwarf pea plant as offspring. Genetics Problem Involving a Monohybrid Cross Possible Points 4 Points Deducted Add a row or column to the tables if necessary. 6. A plant that is heterozygous (Pp) for purple flowers is crossed with a plant that is also heterozygous (Pp) for purple flowers. What will be the genotypes and phenotypes of the F 1 generation? Type the possible gene combinations in the Punnett square and then type the genotype and phenotype ratios in the table below the Punnett square. P = purple flowers (dominant) p = white flowers (recessive) P p P PP Pp p Pp pp Genotypes Phenotypes of Flower Colors # of Each Phenotype (data taken from Punnett square) Ratios of Phenotypes PP Homozygous dominant 1 1:4 Purple flowers Purple flowers Name ______Bennett_ ____ Page 3 of 7 Heredity Pp Heterozygous 2 1:2 pp Homozygous recessive 1 1:4 Testcross Problem to Determine Unknown Genotypes Possible Points 4 Points Deducted Add a row or column to the tables if necessary. 7. This preview has intentionally blurred sections. Sign up to view the full version.

Genotype

A bone is joined to a muscle by which structure?

Test Crosses | Learn Science at Scitable Aa Aa Aa   It is not always possible to determine what genes an organism is carrying by simply looking at its appearance. After all, gene expression is a complex process that is dependant on many environmental and hereditary factors. For example, Gregor Mendel's experiments with pea plants showed how dominant traits can mask recessive ones, thus causing him to muse how "rash it must be... to draw from the external resemblances of hybrids conclusions as to their internal nature" (Mendel, 1866). Today, scientists use the word "phenotype" to refer to what Mendel termed "external resemblance" and the word "genotype" to refer to an organism's "internal nature." Thus, to restate Mendel's musing in modern terms, we cannot infer an organism's genotype by simply observing its phenotype. Indeed, Mendel showed that phenotypic traits can be hidden in one generation, yet reemerge in subsequent generations. This occurs because some alleles are dominant over others, which means that their phenotype will mask the phenotype associated with the recessive alleles. Because of dominance, there is not a one-to-one correspondence between the alleles that an organism possesses (i.e., its genotype) and the organism's observed phenotype. Consider, for instance, the genes that code for eye and body color in the fruit fly Drosophila melanogaster. In these flies, the brown-eye allele (b) is recessive to the normal red-eye allele (B). Similarly, the ebony body color allele (e) is recessive to the normal (yellow-brown) body color allele (E). Because ebony has 100% penetrance , a fly that has dark black body color has the homozygous genotype ee. However, a fly that has a normal body color may have the homozygous genotype EE or the heterozygous genotype Ee. Things get slightly more complex when considering two genes. For instance, a wild-type fly (with red eyes and a yellow body) has one of four possible genotypes: EEBB, EEBb, EeBB, and EeBb. There is no way to tell these genotypes apart visually, but there is a well-established experimental technique to determine the fly's genetic makeup. Specifically, to detect the underlying genotype of an organism with a dominant phenotype, one must do a type of breeding analysis called a test cross. The test cross is another fundamental tool devised by Gregor Mendel. In its simplest form, a test cross is an experimental cross of an individual organism of dominant phenotype but unknown genotype and an organism with a homozygous recessive genotype (and phenotype). In order to understand how test crosses work, it helps to consider several examples, including those that involve just one gene of interest, as well as those that involve multiple genes. Single-Gene Test Crosses Recall that in the fruit fly Drosophila melanogaster, the ebony-body allele (e) is recessive to the normal yellow-body allele (E). Say you are given a male fly with a yellow body. How could you use a test cross to determine this fly's genotype? In order to set up your test cross, you must first realize that the male fly has one of two possible genotypes: Ee or EE. Because the male exhibits the dominant body color phenotype, you must cross it with a female with the homozygous recessive phenotype and genotype. Thus, the male fly is crossed with an ebony-bodied female of genotype ee. Depending on the male fly's underlying genotype, this cross will yield one of two possible sets of outcomes, as depicted in Tables 1 and 2. Table 1: Outcome if Male Fly Is Heterozygous (Ee)  

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What is the biggest bone in the body?

Human Bones: Largest Bone in Body of Humans Information of the world Home » English » Pair of Words » Human Bones: Largest Bone in Body of Humans Bones are very important to give shape to the body, which raises the question which is being the largest bone in the human body. The size and the diameter of the bone depend on the health, height and sex of a person. The size of the biggest bone in human body of a tall man would be different from a man of an average size. Similarly the size and the thickness of different bones in men and women, whether of same height, would also be different. Keeping a single global size as standard, the details of the biggest and the longest bones are: Femur is the largest bone in body . It forms the upper part of human leg. Its average length in adult male is 50.50 centimeter. This bone is also found in mammals, reptiles and vertebrates i.e frog, lizards, amphibians etc. Femur is Latin word which means thigh hence it is also known as thigh bone. Tibia is the second largest bone in the human body and no doubt the strongest bone of human body because it bears the body weight of person. It forms the inner-lower part of human leg. The average length of tibia is 43.03 CM. Tibia is Latin word which means an ancient type of musical instrument. Shin bone and shank bone are other names of Tibia. Fibula (also known as Calf Bone) is located in the outer-lower part of human leg. Fibula is the third largest bone in the human body. Fibula along with Tibia forms the lower part of human leg as it is located on the lateral side of Tibia. It is relatively weak and thin as compared with Tibia. The average length of tibia is 40.50 CM. Humerus bone connects shoulder with elbow in human arm. It is a long bone which consists of three parts i.e. upper extremity of Humerus, body of Humerus and lower extremity of Humerus. Humerus forms the upper part of human arm and many important muscles are attached with it. The average length of tibia is 36.46 CM. Ulna forms the inner-lower part of human arm. This fore-arm bone along with radius completes the lower part of human arm. Its average length in 28.20 Cm. In simple words it connects elbow with hand. It is a long and narrow bone with many muscles attached with it. Radius is a long bone which forms the outer-lower part of human arm. It is on the lateral side of Ulna and its length is 26.42 cm. Radius is also found in some four-leg animals as lower part of forelimb. Like Ulna it connects hand with elbow. 7th rib is part of the 24 ribs found in a human body. The average length of 7th rib is 24.00 CM. Ribs are basically found in Vertebrates and they support the upper body of vertebrates. 8th rib: These long and curved bones are considered as the basic structural part of human body. 8th rib is the part of 12 pairs of ribs in human body. The average length of 8th rib is 23.00 CM. Innominate bone is also called hipbone or half pelvis. It is the 9th largest bone in human body. Its average length is 18.50 Cm. Innominate bone is either of the two bones that form the sides of the pelvis, consisting of three fused components, the ilium, ischium, and pubis Nontechnical name hipbone. Sternum is the tenth largest bone in human body and its average length is 17.00 Cm. It is also called breastbone and it is found in both males and females with the same length. Sternum is a long, flat bone located in the center of the chest, serving as a support for the collarbone and ribs.

Femur

Which of the retina's cells can distinguish between different wavelengths of light?

Longest Bone, Smallest Bone and largest organ in a human body > The femur, THe strirrup bone inside eardrum, skin is the largest human organ. Longest Bone, Smallest Bone and largest organ in a human body English translation: The femur, THe strirrup bone inside eardrum, skin is the largest human organ. Advertisement Login or register (free and only takes a few minutes) to participate in this question. You will also have access to many other tools and opportunities designed for those who have language-related jobs (or are passionate about them). Participation is free and the site has a strict confidentiality policy. GLOSSARY ENTRY (DERIVED FROM QUESTION BELOW) English term or phrase:

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Which hormone causes male sexual development?

Male Hormones About Watch and Favorite Watch Watching this resources will notify you when proposed changes or new versions are created so you can keep track of improvements that have been made. Favorite Favoriting this resource allows you to save it in the “My Resources” tab of your account. There, you can easily access this resource later when you’re ready to customize it or assign it to your students. Male Hormones The onset of puberty is controlled by two major hormones: FSH initiates spermatogenesis and LH signals the release of testosterone. Learning Objective Explain the function of male hormones in reproduction Key Points The onset of puberty is signaled by high pulses of GnRH secreted by the hypothalamus ; this in turn signals the release of FSH and LH from the pituitary gland . FSH causes the Sertoli cells of the testes (which help nurse developing sperm cells) to begin the process of spermatogenesis in the testes. LH triggers the production of testosterone from the Leydig cells of the testis; testosterone causes the development of secondary sex characteristics in the male. As spermatogenesis and testosterone production increase, the Sertoli cells produce inhibin , which, together with rising levels of testosterone, inhibit the release of FSH and LH from the pituitary gland. Terms Male Hormones Puberty is a period of several years in which rapid physical growth and psychological changes occur, culminating in sexual maturity. The average onset of puberty is age 11 or 12 for boys. Some of the most significant parts of pubertal development involve distinctive physiological changes in individuals' height, weight, body composition, and circulatory and respiratory systems. These changes are largely influenced by hormonal activity. Hormones play an organizational role, priming the body to behave in a certain way once puberty begins, and an activational role, referring to changes in hormones during adolescence that trigger behavioral and physical changes. At the onset of puberty, the hypothalamus begins secreting high pulses of GnRH, or gonadotropin-releasing hormone . In response, the pituitary gland releases follicle stimulating hormone (FSH) and luteinizing hormone (LH) into the male system for the first time. FSH enters the testes, stimulating the Sertoli cells, which help to nourish the sperm cells that the testes produce, to begin facilitating spermatogenesis. LH also enters the testes, stimulating the interstitial cells, called Leydig cells, to make and release testosterone into the testes and the blood. Testosterone, the hormone responsible for the secondary sexual characteristics that develop in the male during adolescence, stimulates spermatogenesis, or the process of sperm production in the testes. Secondary sex characteristics include a deepening of the voice, the growth of facial, axillary, and pubic hair, and the beginnings of the sex drive. A negative feedback system occurs in the male with rising levels of testosterone acting on the hypothalamus and anterior pituitary to inhibit the release of GnRH, FSH, and LH . The Sertoli cells produce the hormone inhibin, which is released into the blood when the sperm count is too high. This inhibits the release of GnRH and FSH, which will cause spermatogenesis to slow down. If the sperm count reaches 20 million/ml, the Sertoli cells cease the release of inhibin, allowing the sperm count to increase.

Testosterone

Which part of the brain controls the heart rate?

Androgen (testosterone) deficiency | Andrology Australia Symptoms & causes What are androgens? Hormones are chemical messengers made by glands in the body that are carried in the blood to act on other organs in the body. Hormones are needed for growth, reproduction and well-being. Androgens are male sex hormones that increase at puberty and are needed for a boy to develop into a sexually mature adult who can reproduce. The most important androgen is testosterone. What is testosterone? Testosterone is the most important androgen (male sex hormone) in men and it is needed for normal reproductive and sexual function. Testosterone is important for the physical changes that happen during male puberty, such as development of the penis and testes, and for the features typical of adult men such as facial and body hair. Testosterone also acts on cells in the testes to make sperm. Testosterone is also important for overall good health. It helps the growth of bones and muscles, and affects mood and libido (sex drive). Some testosterone is changed into oestrogen, the female sex hormone, and this is important for bone health in men. Testosterone is mainly made in the testes. A small amount of testosterone is also made by the adrenal glands, which are walnut-sized glands that sit on top of the kidneys. How do hormones control the testes? The pituitary gland and the hypothalamus, located at the base of the brain, control the production of male hormones and sperm. Luteinizing hormone (LH) and follicle stimulating hormone (FSH) are the two important messenger hormones made by the pituitary gland that act on the testes. LH is needed for the Leydig cells in the testes to make testosterone, the male sex hormone. Testosterone and FSH from the pituitary gland then act together on the seminiferous tubules (sperm-producing tubes) in the testes to make sperm. What is androgen (or testosterone) deficiency? Androgen, or testosterone, deficiency is when the body is not able to make enough testosterone for the body to function normally. Although not a life-threatening problem, androgen deficiency can affect your quality of life. How common is androgen deficiency? Androgen deficiency due to diseases of the testes or hypothalamus-pituitary affects about one in 200 men under 60 years of age. It is likely that androgen deficiency is under-diagnosed and that many men are missing out on the benefits of treatment. About one in 10 older men may have testosterone levels lower than those in young men, but this is usually linked with chronic illness and obesity. The benefits of testosterone treatment for such men are not yet known. How does ageing affect testosterone levels? Testosterone levels in men are highest between the ages of 20 and 30 years. As men age there is a small, gradual drop in testosterone levels; they may drop by up to one third between 30 and 80 years of age. Some men will have a greater drop in testosterone levels as they age, especially when they are obese or have other chronic (long-term) medical problems. On the other hand, healthy older men with normal body weight may not experience any drop in serum testosterone levels. There is no such thing as ‘male menopause’ or ‘andropause’ that can be compared to menopause in women. What are the symptoms of androgen deficiency? Low energy levels, mood swings, irritability, poor concentration, reduced muscle strength and low sex drive can be symptoms of androgen deficiency (low testosterone). Symptoms often overlap with those of other illnesses. The symptoms of androgen deficiency are different for men of different ages. Stages Of life • Osteoporosis (thinning of bones) What causes androgen deficiency? Androgen deficiency can be caused by genetic disorders, medical problems, or damage to the testes or pituitary gland. Androgen deficiency happens when there are problems within the testes or with hormone production in the brain. A common chromosomal disorder that causes androgen deficiency is Klinefelter’s syndrome. Diagnosis How is androgen deficiency diagnosed? A diagnosis of androgen deficiency involves having a thorough medical evaluation and at least two blood samples (taken in the morning on different days) to measure hormone levels. Diagnosis should not be simply based on symptoms as these could be caused by other health problems that need different treatment. A diagnosis of androgen deficiency is only confirmed when blood tests show a lower than normal testosterone level. What is the ‘normal’ testosterone range? A reference range is used as a guide by testing laboratories and doctors to decide whether a person’s hormone levels are normal or low, and whether treatment is needed. Testosterone is measured in units called nanomalor. The ‘normal’ testosterone reference range for healthy, young adult men is about 8 to 27 nanomolar but these numbers vary between measurement systems. Treatment How is androgen deficiency treated? Androgen deficiency is treated with testosterone therapy; this means giving testosterone in doses that return the testosterone levels in the blood to normal. Testosterone is prescribed for men with androgen deficiency confirmed by blood tests. Once started, testosterone therapy is usually continued for life and the man needs to be checked regularly by a doctor. What are the main forms of testosterone therapy? In Australia testosterone therapy is available in the form of injections, gels, lotions, creams, patches and tablets, and works very well for men with confirmed androgen (testosterone) deficiency. The type of treatment prescribed can depend on patient convenience, familiarity and cost. Commercial testosterone products contain only the natural testosterone molecule that is chemically produced from plant materials. What are the side-effects of testosterone therapy? Side-effects are not expected because testosterone therapy aims to bring a man’s testosterone levels back to normal. However, testosterone therapy can increase the growth of the prostate gland which can make the symptoms of benign prostate enlargement (such as needing to urinate more often) worse. In the case of prostate cancer, testosterone therapy is not used because of concerns that it can make the tumour grow. Too high a dose of testosterone can lead to acne, weight gain, gynaecomastia (breast development), male-pattern hair loss and changes in mood. Any side-effects should be managed by a doctor and the testosterone dose lowered. Can herbal products help androgen deficiency? There are many herbal products marketed, particularly on the Internet, as treatments that can act like testosterone and improve muscle strength and libido (sex drive). However, there are no known herbal products that can replace testosterone in the body and be used to treat androgen deficiency.  

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What is an overgrowth of fibrous tissue, usually produced at the site of a scar?

Keloid Scar of Skin: Symptoms, Causes, and Treatments Keloid Scar of Skin Email addresses will not be shared with 3rd parties. See privacy policy Thank you. Your message has been sent. OK We're sorry, an error occurred. We are unable to collect your feedback at this time. However, your feedback is important to us. Please try again later. Close Key points Keloids are smooth, hard, benign growths that form when scar tissue grows excessively. Risk factors include being of African, Asian, or Latino heritage, being pregnant, and being younger than 30 years old. Treatments for keloid scarring are not always effective. When skin is injured, fibrous tissue, called scar tissue, forms over the wound to repair and protect the injury. In some cases, scar tissue grows excessively, forming smooth, hard growths called keloids. Keloids can be much larger than the original wound. They’re most commonly found on the chest, shoulders, earlobes, and cheeks. However, keloids can affect any part of the body. Although keloids aren’t harmful to your health, they may create cosmetic concerns. Picture What symptoms are associated with keloids? Keloids occur from the overgrowth of scar tissue. Symptoms occur at a site of previous skin injury. The symptoms of keloids can include: a localized area that is flesh-colored, pink, or red in color a lumpy or ridged area of skin that’s usually raised an area that continues to grow larger with scar tissue over time an itchy patch of skin Keloid scars tend to be larger than the original wound itself. They may take weeks or months to develop fully. While keloid scars may be itchy, they’re usually not harmful to your health. You may experience discomfort, tenderness, or possible irritation from your clothing or other forms of friction. In rare instances, you may experience keloid scarring on a significant amount of your body. When this occurs, the hardened, tight scar tissue may restrict your movements. Keloids are often more of a cosmetic concern than a health one. You may feel self-conscious if the keloid is very large or in a highly visible location, such as an earlobe or on the face. Sun exposure or tanning may discolor the scar tissue, making it slightly darker than your surrounding skin. This can make the keloid stand out even more than it already does. Keep the scar covered when you’re in the sun to prevent discoloration. What causes the condition? being pregnant being younger than 30 Keloids tend to have a genetic component, which means you’re more likely to have keloids if one or both of your parents has them. According to a study conducted at Henry Ford Hospital in Detroit, Michigan, a gene known as the AHNAK gene may play a role in determining who develops keloids and who doesn’t. The researchers found that people who have the AHNAK gene may be more likely to develop keloid scars than those who don’t. If people have known risk factors for developing keloids, they may want to avoid getting body piercings, unnecessary surgeries, or tattoos. When to seek medical attention Keloids typically don’t require medical attention, but you may want to contact your doctor if growth continues, you develop additional symptoms, or you want to have the keloids surgically removed. Keloids are benign, but uncontrolled growth may be a sign of skin cancer. After diagnosing keloid scarring by visual exam, your doctor may want to perform a biopsy to rule out other conditions. This involves taking a small sample of tissue from the scarred area and analyzing it for cancerous cells. Find a Doctor How is the condition treated? The decision to treat a keloid can be a tricky one. Keloid scarring is the result of the body’s attempt to repair itself. After removing the keloid, the scar tissue may grow back again, and sometimes it grows back larger than before. Examples of keloid treatments include: corticosteroid injections to reduce inflammation moisturizing oils to keep the tissue soft using pressure or silicone gel pads after injury freezing the tissue to kill skin cells laser treatments to reduce scar tissue radiation to shrink keloids Initially, your doctor will probably recommend less invasive treatments, such as applying silicone pads, pressure dressings, or injections. These treatments require frequent and careful application to prove effective. However, keloids tend to shrink and become flatter over time even without treatment. In the instance of very large keloids, surgical removal may be indicated. According to the Dermatology Online Journal , the rate of keloid scarring coming back can be high after surgery. Your doctor may recommend steroid injections after surgery to lower the risk of the keloid returning. Long-term outlook Although they rarely cause adverse side effects, keloids can be an annoying and sometimes physically embarrassing occurrence. Treatments for keloid scarring can be difficult and not always effective. For this reason, it’s important to try to prevent skin injuries that could lead to keloid scarring.

Keloid

Which is the only vein in the body to carry oxygenated blood?

Epi-Derm Silicone Gel Strip - DirectDermaCare Free Shipping* on your Entire Order From DirectDermaCare Home / Epi-Derm Silicone Gel Strip Epi-Derm Silicone Gel Strip $54.99 Free shipping in the USA | Low International Shipping This Siliscone Gel Sheet is long and narrow. It is intended for slit style scars that tend to follow surgery on the stomach. Epi-Derm™ Long Silicone Gel Sheet   Epi-derm™ is a soft silicone gel sheet which is tacky on the back and easy to apply. Epi-derm™ silicone gel sheeting is the most effective, proven method of scar management available today. All Epi-Derm™ sheets can be trimmed as needed.   The strip is ideal for surgical scars resulting from C-section, tummy tuck and cardiac procedures. Size 3.5 x 29 cm / 1.4 x 11.5 in How Does it Work?  Scars need an “ideal healing environment,” meaning the appropriate balance of moisture and maximum exposure to oxygen. Epi-derm™ is a fully-encapsulating sheet — it completely covers the scar treatment site for uniform treatment of the entire site. Although the entire site is covered, Epi–derm™ is semi-permeable, allowing oxygen to enter while keeping excess moisture out — the ideal environment for healing scar tissue.   Rated: 4.6 / 5 based on 16 customer reviews Epiderm FAQ Keloids, and How Epi-Derm Can Help Prevent Them Keloids are the aftereffect of an overgrowth of dense fibrous tissue that usually develops after healing of a skin injury. When a scar is formed, connective tissues or fibers are formed at the site to hold the wound closed. Keloids form when the cells continue to multiply after the wound is filled in. Symptoms may include pigmentation of the skin, discomfort, or an itchy or painful sensation. Scar treatment therapy options include silicone sheets for keloids, and pressure treatment. Keloids may often be prevented by using a pressure dressing like Epi-Net in conjunction with silicone scar strips over the injury site 24 hours each day. This treatment is most effective after healing of the wound or injury, usually within a month. How is Epi-Derm best used? Epi-Derm, Pro-Sil, and Xeragel should be applied for a minimum of 12 hours per day for 8-12 weeks. Once gel sheeting has been applied to the scar site, it can be used for 1-2 weeks. When it begins to lose its adhesive qualities, or when surface dirt becomes difficult to remove with proper daily washing, it is time to replace the sheet. Epi-Derm scar silicone sheets may be cut into smaller pieces using clean scissors or a knife. The piece of gel sheeting should fully cover the scar and extend 1/4 inch all the way around the scar border. We recommend that you store unused product in its original packaging at room temperature. Always apply the sticky side of the silicone sheets to the scar! It is necessary to remove silicone sheeting for scars when you shower, workout or swim due to the excessive moisture. Nothing should be used underneath Epi-Derm gel sheeting (between the gel sheeting and your scar). Of course, Pro-Sil and Xeragel are frequently used during the day on exposed scars (face, hands, elbows, etc.) for 24 hour a day usage. Many patients prefer Epi-Derm scar silicone sheets at night when they are at home or sleeping, because a single sheet will last all night. Unused product, whether opened, or unopened, will last for years when stored properly. When should I use Epi-Derm, and How Effective is it? Epi-Derm can be applied as soon as sutures have been removed, and the scab is no longer present. Epi-Derm can be effective on older scars, however clinical studies have shown the newer the scar, the better the results. One such study found a success rate of scar reduction up to 85% on scars under 1 year old, and a rate of about 65% for scars over 10 years old. Can Epi-Derm be used on facial scars? Yes, Epi-Derm silicone strips work great on facial scars. Frequently, patients choose to use Pro-Sil or Xeragel on facial scars during the day because these products are less noticeable, then use Epi-Derm scar silicone sheets at night. Unlike many over the counter scar reduction products, Epi-Derm, Pro-Sil and Xeragel are made of medical grade silicone. Epi-Derm is safe and non-toxic and can be used on children. Each product has received U.S. FDA clearance and European C.E. mark and is comprised of safe, non-toxic, non-medicated, semi-occlusive silicone gel. If you like Epi-Derm Silicone Gel Strip , you may also be interested in these related products: VitOptics Premier Omega-3 Fish Oil VitOptics Omega-3 Fish Oil Natural Lemon Softgels are the premier physician recommended pharmaceutical grade Omega-3 formula. The Omega-3 Fish Oil in the...

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Which human body organ weighs about 2 kilos?

≡ List of Human Organs + All Sizes, Functions, Tasks, Weights & Facts 23.8 Over the skeleton around the body At up to 1.95 square meters (21 sq ft) The “derma” is the largest of all human organs and one of the heaviest weighing between 6-10% of body weight. Oil glands stop skin drying out. Skin cells are continuously shedded and replaced. Skin is a versatile organ with an ideal pH value of 5.5. Responds to external stimuli (touch, heat) and uses sweat to cool the body and raised hairs (goosebumps) to trap heat and warm the body regulating the overall temperature. Protects us from UV radiation and injury by producing thick skin (calluses). Liver 3.1 Upper right abdominal cavity just beneath the diaphragm Largest gland in the body. The “Iecur” or “hepar” has a soft smooth surface, left and right lobes and weighs between 1.4-2 kg (3-4.4 lbs). The tissue consists of around 100,000 lobules. Stores energy reserves ( vitamins and carbohydrates), detoxifies and breaks down nutrients, produces vital proteins (clotting factors). Brain 3.0 Inside the skull The female “cerebrum” weighs around 1.2 kg (2.8 lbs) compared to 1.4 kg (3 lbs) for males. The brain consumes between 20-25% of our total energy intake. The brain consists of 100 billion neurons (somata) and 100 trillion synapses. The neural pathways are 5.8 km (3.6 miles) long in total. We distinguish between: cerebrum, cerebellum, diencephalon and trunk. Processes sensory inputs, coordinates behavior and saves information; cerebrum (perception, thinking, acting), diencephalon (feelings like love, fear, anger etc.), cerebellum (balance while walking, running, dancing etc). Lungs 2.4 Inside chest rib cage The “pulmo” typically weighs just over 1kg (2.2 lbs) and has a volume between 5-6 liters (10.5-12.7 US pints) with 400 million alveoli. The (smaller) left lung consists of two lobes, the right one of three lobes. Gas exchange between air and bloodstream. In other words absorption of oxygen and release of carbon dioxide from the body. Heart 0.8 Under ribcage between your left and right lungs The “cor” or “cardia” is a fist-sized, hollow, muscular human organ weighing between 300-350g (10-12 oz), the right and left side of the heart each consist of a chamber and an atrium. Of all the human organs the heart is most impressive. At rest it can pump 4.9 liters of blood per minute through our veins. Under duress this can rise to between 20-25 liters of blood per minute. Kidney 0.7 Under ribcage in lower back Both kidneys (“ren” or “nephros”) weigh about 300 g (10½ oz). Between them the 1.2 million renal corpuscles filter up to 1500 liters (400 US gallons) of blood daily. Purifies the blood and filters out toxins from the body, controls the water balance of the body, excretion of waste products through urine production. Spleen 0.4 Below rib cage on your left side The spleen is about the size of a fist and weighs between 150 and 200 grams (5-7 oz). It’s located on the abdomen on the left kidney and below the diaphragm. Produces red and white blood cell pulp helping the immune system fight infections. Pancreas 0.22 Behind stomach in abdomen Wedge shaped organ between 16-20 cm long, 3-4 cm wide and up to 2 cm (3/4″) thick. Weighs around 100 grams (3½ oz). The pancreas is a dual function organ which produces enzymes to digest our stomach contents, separating fats, proteins and carbs. The pancreas also regulates blood sugar by producing two hormones, insulin and glucagon which have opposite effects. Thyroid 1.65 Immediately above and behind the pubic bone The “vesica urinaria” holds up to 550 ml (1.2 US pints) of urine (or with some men even up to 750 ml (1.6 US pints) Ureters connect the kidneys to the bladder and transport the purified blood (urine) to the bladder. Stores the urine resulting from the blood purification in the kidneys and removes all toxins (urea, chlorides, sodium, potassium, creatine, bicarbonate, uric acid) from the body through excretion. Blood   In blood vessels (arteries, veins, capillaries etc.) An average 5-7 liters (10.6-14.8 US pints) of “Sanguis” flows through our body on average. It consists of 56% plasma and 44% blood cells (red = erythrocytes, white = leukocytes, platelets (thrombocytes), sugar 0.1%. Blood plasma transports nutrients and waste materials; red cells transport oxygen and carbon dioxide, the white cells fight off pathogens, and the platelets are responsible for blood clotting. Diaphragm   Separates chest cavity from abdominal cavity. The diaphragm is the most important respiratory muscle and consists of muscles and tendons. It’s dome-shaped, about 3-5 cm (1¼-2″) thick. The diaphragm pumps 60-80% of the air breathed in into the lungs through contractions of the bronchi (at rest). The contractions cause the chest to rise and fall. A spasm of the diaphragm often causes hiccups. Gallbladder   below liver near duodenum The “vesica fellea” is a 6-10 cm (2.3-4″) long pear-shaped hollow human organ with a maximum width of 4 cm (1½”). Produces bile, which is needed for (fat) digestion. Intestines 4.41 Abdominal body cavity The small and large intestines are about 8 metres (26¼ feet) long and weighs 2 kg (4½ pounds). The intestines include the duodenum, blank, ileum and colon (blind, Grimm and rectum. Digestion and absorption of food (protein, carbohydrates, salts, vitamins and fats) Extracts fluids from food pulp Excretion of stools. 88.18 Around the body The 656 muscles together weigh between 30-40 kg (66-88 pounds). Every muscle is composed of elastic connective tissue, up to 12 fibers, and cells. Support entire movement processes, form the basis of active locomotion and the functioning of many internal body functions. Skeleton   Under the skin The “skeletos” in an adult consists of 206-214 bones, the spine of 33 vertebrae. The skeleton accounts for about 12% of body weight. Carries and supports the entire body structure. The skeleton and bones aren’t fixed, rigid structures. On the contrary, they are alive and adapt to circumstances, heal fractures and renew constantly. They grow until about age 25. After 40 bone degradation begins. Vessels / veins

Liver

Which name is given to the heart chamber which receives blood?

Normal organ weights in men: part II-the brain, lungs, liver, spleen, and kidneys. - PubMed - NCBI Am J Forensic Med Pathol. 2012 Dec;33(4):368-72. doi: 10.1097/PAF.0b013e31823d29ad. Normal organ weights in men: part II-the brain, lungs, liver, spleen, and kidneys. 1Bexar County Medical Examiner's Office, San Antonio, TX 78229, USA. [email protected] Abstract Organomegaly can be a sign of disease and pathologic abnormality, although standard tables defining organomegaly have yet to be established and universally accepted. This study was designed to address the issue and to determine a normal weight for the major organs in adult human males. A prospective study of healthy men aged 18 to 35 years who died of sudden, traumatic deaths was undertaken. Cases were excluded if there was a history of medical illness including illicit drug use, if prolonged medical treatment was performed, if there was a prolonged period between the time of injury and death, if body length and weight could not be accurately assessed, or if any illness or intoxication was identified after gross and microscopic analysis including evidence of systemic disease. Individual organs were excluded if there was significant injury to the organ, which could have affected the weight. A total of 232 cases met criteria for inclusion in the study during the approximately 6-year period of data collection from 2005 to 2011. The decedents had a mean age of 23.9 years and ranged in length from 146 to 193 cm, with a mean length of 173 cm. The weight ranged from 48.5 to 153 kg, with a mean weight of 76.4 kg. Most decedents (87%) died of either ballistic or blunt force (including craniocerebral) injuries. The mean weight of the brain was 1407 g (range, 1070-1767 g), that of the liver was 1561 g (range, 838-2584 g), that of the spleen was 139 g (range, 43-344 g), that of the right lung was 445 g (range, 185-967 g), that of the left lung was 395 g (range, 186-885 g), that of the right kidney was 129 g (range, 79-223 g), and that of the left kidney was 137 g (range, 74-235 g). Regression analysis was performed and showed that there were insufficient associations between organ weight and body length, body weight, and body mass index to allow for predictability. The authors, therefore, propose establishing a reference range for organ weights in men, much like those in use for other laboratory tests including hemoglobin, hematocrit, or glucose. The following reference ranges (95% inclusion) are proposed: brain, 1179-1621 g; liver, 968-1860 g; spleen, 28-226 g; right lung, 155-720 g; left lung, 112-675 g; right kidney, 81-160 g; and left kidney, 83-176 g. PMID:

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What kind of joint is the hip?

Hip Joint - Anatomy Pictures and Information Hip Joint Home > Skeletal System > Bones of the Leg and Foot > Hip Joint Hip Joint The hip joint is one of the most important joints in the human body. It allows us to walk, run, and jump. It bears our body’s weight and the force of the strong muscles of the hip and leg. Yet the hip joint is also one of our most flexible joints and allows a greater range of motion than all other joints in the body except for the shoulder. The hip joint is a ball-and-socket synovial joint formed between the os coxa (hip bone) and the femur. A round, cup-shaped structure on the os coax, known as the acetabulum, forms the socket for the hip joint. The rounded head of the femur... Move up/down/left/right: Click compass arrows Rotate image: Click and drag in any direction, anywhere in the frame Identify objects: Click on them in the image 2D Interactive 3D Rotate & Zoom Change Anatomical System Full Hip Joint Description [Continued from above] . . . forms the ball of the joint. Hyaline cartilage lines both the acetabulum and the head of the femur, providing a smooth surface for the moving bones to glide past each other. Hyaline cartilage also acts as a flexible shock absorber to prevent the collision of the bones during movement. Between the layers of hyaline cartilage, synovial membranes secrete watery synovial fluid to lubricate the joint capsule. Surrounding the hip joint are many tough ligaments that prevent the dislocation of the joint. The strong muscles of the hip region also help to hold the hip joint together and prevent dislocation. Functionally, the hip joint enjoys a very high range of motion. The ball-and-socket structure of the joint allows the femur to circumduct freely through a 360-degree circle. The femur may also rotate around its axis about 90 degrees at the hip joint. Only the shoulder joint provides as high of a level of mobility as the hip joint. In addition to being flexible, each hip joint must be capable of supporting half of the body’s weight along with any other forces acting upon the body. During running and jumping, for example, the force of the body’s movements multiplies the force on the hip joint to many times the force exerted by the body’s weight. The hip joint must be able to accommodate these extreme forces repeatedly during intense physical activities. If a knee or hip joint breaks in an accident or wears out in old age, a surgeon can replace it with a ball-and-socket joint made from metal and plastic and engineered in such a way that it will duplicate the motions of a human joint. Hip replacement was once impossible because, although joints could easily be produced in a laboratory, the human body rejected the materials. Sometimes the pins that held the artificial joint to other bones worked loose and required further surgery. Some joints, especially the artificial knee, didn't work very well because they were designed like hinges that just opened one way. Later, when the designers realized the knee needed to rotate slightly, they produced a joint that would fulfill these movements as well. Medical pioneers finally overcame bodily rejection by making the joints out of non-irritating, man-made materials. Surgeons have now perfected hip and knee replacement surgeries so that recipients are relieved of pain and can walk at a smoother pace. Prepared by Tim Taylor, Anatomy and Physiology Instructor

Ball and socket joint

Where is the sinoatrial node?

Osteoarthritis of the Hip-OrthoInfo - AAOS Copyright 2014 American Academy of Orthopaedic Surgeons Osteoarthritis of the Hip Information on hip osteoarthritis is also available in Spanish: Osteoartritis de cadera Osteoartritis de cadera (topic.cfm?topic=A00608). Sometimes called "wear-and-tear" arthritis, osteoarthritis is a common condition that many people develop during middle age or older. In 2011, more than 28 million people in the United States were estimated to have osteoarthritis. It can occur in any joint in the body, but most often develops in weight-bearing joints, such as the hip. Osteoarthritis of the hip causes pain and stiffness. It can make it hard to do everyday activities like bending over to tie a shoe, rising from a chair, or taking a short walk. Because osteoarthritis gradually worsens over time, the sooner you start treatment, the more likely it is that you can lessen its impact on your life. Although there is no cure for osteoarthritis, there are many treatment options to help you manage pain and stay active. Anatomy The hip is one of the body's largest joints. It is a "ball-and-socket" joint. The socket is formed by the acetabulum, which is part of the large pelvis bone. The ball is the femoral head, which is the upper end of the femur (thighbone). The bone surfaces of the ball and socket are covered with articular cartilage, a smooth, slippery substance that protects and cushions the bones and enables them to move easily. The surface of the joint is covered by a thin lining called the synovium. In a healthy hip, the synovium produces a small amount of fluid that lubricates the cartilage and aids in movement. The anatomy of the hip. Top of page Description Osteoarthritis is a degenerative type of arthritis that occurs most often in people 50 years of age and older, though it may occur in younger people, too. In osteoarthritis, the cartilage in the hip joint gradually wears away over time. As the cartilage wears away, it becomes frayed and rough, and the protective joint space between the bones decreases. This can result in bone rubbing on bone. To make up for the lost cartilage, the damaged bones may start to grow outward and form bone spurs (osteophytes). Osteoarthritis develops slowly and the pain it causes worsens over time. A hip damaged by osteoarthritis. Animation courtesy Visual Health Solutions, Inc. Top of page Cause Osteoarthritis has no single specific cause, but there are certain factors that may make you more likely to develop the disease, including: Increasing age Previous injury to the hip joint Obesity Improper formation of the hip joint at birth, a condition known as developmental dysplasia of the hip Even if you do not have any of the risk factors listed above, you can still develop osteoarthritis. Top of page Symptoms The most common symptom of hip osteoarthritis is pain around the hip joint. Usually, the pain develops slowly and worsens over time, although sudden onset is also possible. Pain and stiffness may be worse in the morning, or after sitting or resting for a while. Over time, painful symptoms may occur more frequently, including during rest or at night. Additional symptoms may include: Pain in your groin or thigh that radiates to your buttocks or your knee Pain that flares up with vigorous activity Stiffness in the hip joint that makes it difficult to walk or bend "Locking" or "sticking" of the joint, and a grinding noise (crepitus) during movement caused by loose fragments of cartilage and other tissue interfering with the smooth motion of the hip Decreased range of motion in the hip that affects the ability to walk and may cause a limp Increased joint pain with rainy weather Top of page Doctor Examination During your appointment, your doctor will talk with you about your symptoms and medical history, conduct a physical examination, and possibly order diagnostic tests, such as x-rays. Physical Examination During the physical examination, your doctor will look for: Tenderness about the hip Range of passive (assisted) and active (self-directed) motion Crepitus (a grating sensation inside the joint) with movement Pain when pressure is placed on the hip Problems with your gait (the way you walk) Any signs of injury to the muscles, tendons, and ligaments surrounding the hip Imaging Tests X-rays. These imaging tests create detailed pictures of dense structures, like bones. X-rays of an arthritic hip may show a narrowing of the joint space, changes in the bone, and the formation of bone spurs (osteophytes). (Left) In this x-ray of a normal hip, the space between the ball and socket indicates healthy cartilage. (Right) This x-ray of an arthritic hip shows severe loss of joint space and bone spurs. Other imaging tests. Occasionally, a magnetic resonance imaging (MRI) scan, a computed tomography (CT) scan, or a bone scan may be needed to better determine the condition of the bone and soft tissues of your hip. Top of page Treatment Although there is no cure for osteoarthritis, there are a number of treatment options that will help relieve pain and improve mobility. Nonsurgical Treatment As with other arthritic conditions, early treatment of osteoarthritis of the hip is nonsurgical. Your doctor may recommend a range of treatment options. Lifestyle modifications. Some changes in your daily life can protect your hip joint and slow the progress of osteoarthritis. Minimizing activities that aggravate the condition, such as climbing stairs. Switching from high-impact activities (like jogging or tennis) to lower impact activities (like swimming or cycling) will put less stress on your hip. Losing weight can reduce stress on the hip joint, resulting in less pain and increased function. Physical therapy. Specific exercises can help increase range of motion and flexibility, as well as strengthen the muscles in your hip and leg. Your doctor or physical therapist can help develop an individualized exercise program that meets your needs and lifestyle. Assistive devices. Using walking supports like a cane, crutches, or a walker can improve mobility and independence. Using assistive aids like a long-handled reacher to pick up low-lying things will help you avoid movements that may cause pain. Medications. If your pain affects your daily routine, or is not relieved by other nonsurgical methods, your doctor may add medication to your treatment plan. Acetaminophen is an over-the-counter pain reliever that can be effective in reducing mild arthritis pain. Like all medications, however, over-the-counter pain relievers can cause side effects and interact with other medications you are taking. Be sure to discuss potential side effects with your doctor. Nonsteroidal anti-inflammatory drugs (NSAIDs) may relieve pain and reduce inflammation. Over-the-counter NSAIDs include naproxen and ibuprofen. Other NSAIDs are available by prescription. Corticosteroids (also known as cortisone) are powerful anti-inflammatory agents that can be taken by mouth or injected into the painful joint. Surgical Treatment Your doctor may recommend surgery if your pain from arthritis causes disability and is not relieved with nonsurgical treatment. Osteotomy. Either the head of the thighbone or the socket is cut and realigned to take pressure off of the hip joint. This procedure is used only rarely to treat osteoarthritis of the hip. Hip resurfacing. In this hip replacement procedure, the damaged bone and cartilage in the acetabulum (hip socket) is removed and replaced with a metal shell. The head of the femur, however, is not removed, but instead capped with a smooth metal covering. Total hip replacement. Your doctor will remove both the damaged acetabulum and femoral head, and then position new metal, plastic or ceramic joint surfaces to restore the function of your hip. In total hip replacement, both the head of the femur and the socket are replaced with an artificial device. Animation courtesy Visual Health Solutions, Inc. Complications. Although complications are possible with any surgery, your doctor will take steps to minimize the risks. The most common complications of surgery include: Infection Top of page Recovery After any type of surgery for osteoarthritis of the hip, there is a period of recovery. Recovery time and rehabilitation depends on the type of surgery performed. Your doctor may recommend physical therapy to help you regain strength in your hip and to restore range of motion. After your procedure, you may need to use a cane, crutches, or a walker for a time. In most cases, surgery relieves the pain of osteoarthritis and makes it possible to perform daily activities more easily. Source: National Estimates: Osteoarthritis. Department of Research & Scientific Affairs, American Academy of Orthopaedic Surgeons. Rosemont, IL: AAOS; January 2013. Based on Lawrence RC, Felson DT, Helmick CG, et al. Estimates of the prevalence of arthritis and other rheumatic conditions in the United States. Part II. Arthritis Rheum 2008;58(1):26-35 and U.S. Census Bureau, Population Division, 2011. Top of page Last reviewed: July 2014 AAOS does not endorse any treatments, procedures, products, or physicians referenced herein. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopaedic advice or assistance should consult his or her orthopaedic surgeon, or locate one in your area through the AAOS "Find an Orthopaedist" program on this website. Copyright 2014 American Academy of Orthopaedic Surgeons Related Articles

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What is the substance that the body over-produces in an allergic reaction to pollen?

What Exactly Is an Allergy? Insect Allergies What is Happening During an Allergic Reaction? During an allergic process, the substance responsible for causing the allergy , or allergen, binds to allergic antibodies present on allergic cells in a person's body, including mast cells and basophils. These cells then release chemicals such as histamine and leukotrienes, resulting in allergic symptoms. How do Allergies Start? The allergic person can make allergic antibodies, or IgE, against a variety of allergens, including pollens , molds, animal danders, dust mites, foods, venoms and medications. This occurs through a process called sensitization, where a person’s immune system is exposed to enough of the allergen to make the body produce allergic antibodies to that substance. With later exposures, that same allergen binds to its corresponding IgE on allergic cells, and the body reacts with symptoms of allergies. Allergic symptoms can vary somewhat with the type of allergen and route of exposure (airborne pollen exposure may cause different symptoms than eating a food to which you are allergic). When and Why do People Develop Allergies? It is unknown why some people develop allergies and some don’t. Allergies seem to run in families, and in some cases, family members can share allergies to specific foods or medications. It appears that the allergic response was once meant to protect the body against parasitic infections, although now seems to be an abnormal response to non-infectious triggers. Allergies can occur at any time during our lives, but are more common to occur during childhood or young adulthood.

Histamine

Which organ of the body secretes insulin?

The Process of an Allergic Reaction - City Allergy - New York Allergy Doctor City Allergy Category: Patient Education > About Allergies    The Process of an Allergic Reaction All allergic diseases including asthma, rhinitis, sinusitis, and anaphylaxis are the result of the mobilization of the immune system in response to a foreign substance in the body. In order to first develop allergies, the body must be exposed to something in the environment that prompts it to initiate an immune response. These foreign substances, called allergens, can be something we have swallowed, something we have inhaled, something we have touched, or something injected into us like a needle or an insect sting. When an allergen enters our body, a person with an inherited predisposition to this allergen will begin to develop a specific type of antibody called immunoglobin E (IgE). An antibody is a protein produced by our immune system, which circulate in the bloodstream and help to remove any substances or organisms, such as bacteria or viruses, which has invaded our body. The IgE antibody is one of five different classes of antibody made by our immune system. The other four are: IgM, IgG, IgD, and IgA. IgE antibodies originally evolved to give the body a way of protecting itself from parasites. However, it is also specifically targeted at allergens. Although everyone makes IgE, people whom are prone to allergic reactions make much larger quantities. Inheritance has a major influence on allergies. Inheritance determines whether or not a person makes IgE in response to everyday substances. Although it is unlikely that there’s a single gene behind allergies in all allergic individuals, you are still more likely to have allergies if other members of your family have them. Researchers say that if you have 1 sibling with allergies, you have a 33% chance of having them. If you have 1 parent that is allergic, you have a 50% chance, and if you have 2 parents with allergies, you have a 75-80% chance of being allergic. Other influences such as viral infections, smoking, and hormones can also determine whether one develops allergies. All immunoglobins including IgE are made by B-lymphocytes, a specific type of white blood cell. The B-lymphocyte’s antibody production is regulated by Helper T-lymphocytes, another type of white blood cell. In addition, macrophages, cells that ingest pieces of foreign substances, assist T-lymphocytes to prompt B-lymphocytes to make more IgE. When an allergic individual is exposed to a sensitizing allergen, the body makes a specific IgE, one that is able to recognize only that allergen. (see above chart) Millions of mast cells and basophils are all over the body. Mast cells reside in tissues in the body, and basophils are in the blood stream. Both mast cells and basophils have over 100,000 receptors that are specific for the IgE antibody. When an allergen (antigen) enters the immune system, the antigen binds to these IgE receptors on the surface of the cells. When the allergic individual is reexposed to the same allergen that initiated the response, the IgE is able to bind to that allergen. When two IgE antibodies next to each other bind to the antigen, this interaction “wiggles” the membrane and causes the degranulation of the mast cell or basophil. Degranulation means the breaking down of the mast cell or basophil. As degranulation occurs, it causes the mast cell or basophil to release a series of chemicals that orchestrate the allergic reaction. Within every mast cell or basophil are 500 to 1500 granules containing more than thirty different allergy-causing chemicals. The best known chemical that is released is histamine. Histamine causes itching if released in the skin, wheezing if released in the lung, and contributes to a loss of blood pressure if released throughout the body. Leukotrienes are also released, and they act similar to histamines. Cytokines are also released, and one of the cytokines released by the basophil is interleukin-4, which is believed to be responsible for telling the body to make more IgE. (See Allergic Rhinitis for effects of allergy causing chemicals on the body). The intensity of this immune response is one of the many reasons that antihistamines alone do not work for most allergic disease. The phases of an immune response Once the mast cells and/or basophils have released their chemicals, the allergic reaction occurs rather quickly. This part of the reaction is called the immediate reaction. However, some people also experience what is called a late phase reaction. The tissues in which mast cells have released their chemicals may become hot, tender, red and swollen for several hours. The mast cells create this reaction by releasing chemicals, called chemotactic factors, that then attract many other inflammatory cells to the site. These cells include: eosinophils, neutrophils, and lymphocytes. Once they’ve arrived, each one of these cells contributes to the late phase of the allergic response. Eosinophils generate chemicals similar to those made by mast cells, as well as release more generally toxic substances that irritate the body. Neutrophils release a number of chemicals including enzymes, which degrade proteins, and in turn cause further tissue damage. The immediate and late phase reactions together combine to form a severe allergic response. In skin reactions, the immediate phase consists of a pale central area surrounded by redness and swelling. This response reaches its peak at about 15 minutes and goes away after about 90 minutes. However, the immediate response can also merge with the late phase that can last up to 24 hours. In the nose, the immediate response consists of sneezing, itching, and the production of nasal secretions. The late phase response is associated with swelling, constant blockage of the nasal passages, and continuous mucus production. In the lung, the immediate response begins within minutes or even seconds after exposure to an allergen. This includes shortness of breath, wheezing, and coughing. This disappears after an hour or so. Three to four hours later, the late phase reaction begins. It is also characterized by shortness of breath and coughing, and can last up to 24 hours. If the allergic response sounds very confusing, you’re right!!! That is why it is so difficult to treat allergies with a single medication. The immune response is an endless cycle that constantly produces IgE antibodies and other chemicals, and therefore causes continuing allergic symptoms. At this time, we cannot cure allergies, we can only hope to contain them. Due to the complexity of the allergic cascade multiple drugs are often needed to control symptoms. Alternatives including allergy desensitization shots which reduce the overall reactivity of the immune system may be explored with your doctor.

i don't know

Which part of the gut absorbs water from thje food?

Absorption of Water and Electrolytes Glossary Absorption of Water and Electrolytes The small intestine must absorb massive quantities of water. A normal person or animal of similar size takes in roughly 1 to 2 liters of dietary fluid every day. On top of that, another 6 to 7 liters of fluid is received by the small intestine daily as secretions from salivary glands, stomach, pancreas, liver and the small intestine itself. By the time the ingesta enters the large intestine, approximately 80% of this fluid has been absorbed. Net movement of water across cell membranes always occurs by osmosis , and the fundamental concept needed to understand absorption in the small gut is that there is a tight coupling between water and solute absorption. Another way of saying this is that absorption of water is absolutely dependent on absorption of solutes, particularly sodium: Sodium is absorbed into the cell by several mechanisms, but chief among them is by cotransport with glucose and amino acids - this means that efficient sodium absorption is dependent on absorption of these organic solutes. Absorbed sodium is rapidly exported from the cell via sodium pumps - when a lot of sodium is entering the cell, a lot of sodium is pumped out of the cell, which establishes a high osmolarity in the small intercellular spaces between adjacent enterocytes. Water diffuses in response to the osmotic gradient established by sodium - in this case into the intercellular space. It seems that the bulk of the water absorption is transcellular, but some also diffuses through the tight junctions. Water, as well as sodium, then diffuses into capillary blood within the villus. Examine the animation above and consider the osmotic gradient between the lumen and the intercellular space (inside the villus). As sodium (green balls) is rapidly pumped out of the cell, it achieves very high concentration in the narrow space between enterocytes. The osmotic gradient is thus formed across apical cell membranes and their connecting junctional complexes. The arrow that appears denotes movement of water across the epithelium. Water is thus absorbed into the intercellular space by diffusion down an osmotic gradient. However, looking at the process as a whole, transport of water from lumen to blood is often against an osmotic gradient - this is important because it means that the intestine can absorb water into blood even when the osmolarity in the lumen is higher than osmolarity of blood. This ability is best explained by the " three compartment model " for absorption of water and, like many aspects of gut permeability, varies along the length of the gut. The proximal small intestine functions as a highly permeable mixing segment, and absorption of water is basically isotonic. That is, water is not absorbed until the ingesta has been diluted out to just above the osmolarity of blood. The ileum and especially the colon are able to absorb water against an osmotic gradient of several hundred milliosmols.

Colon

Where would you find the islets of Langerhans?

doesn't small intestine absorb water? | Student Doctor Network doesn't small intestine absorb water? joonkimdds Senior Member 7+ Year Member Joined: I just took a kaplan exam and a question says "Water absorption occurs primarily in the A. duodenum. D. large intestine. E. mouth." explanation says "The large intestine is primarily involved in water reabsorption" and the answer is D. But I think small intestine absorb water. My class note says most of water is actually absorbed in small intestine. What large intestine absorbs is basically left-over water that small intestine couldn't finish absorbing. I am confused. SDN Members don't see this ad. About the ads. gentile1225 5+ Year Member Status: Pre-Dental No, Kaplan is correct. The large intestine, aka the colon, is responsible for the most reabsorption of water in the body. Whereas, the small intestine is responsible for most digestion.   Status: Pre-Dental Also, the duodenum and the jejunum are both parts of the small intestine so that could have helped to eliminate 2 answers. Also, the stomach's main function is the storage of food.   joonkimdds Senior Member 7+ Year Member Joined: I am not sure about that. I am looking at the power point slides from human physiology class. it says. "Most digestion and absorption takes place in the small intestine protein...carbohydrates...lipids...nucleic acids *I didn't put !! next water. My professor did. and small intestine from wikipedia says "Water and lipids are absorbed by passive diffusion throughout" and this website http://www.vivo.colostate.edu/hbooks/pathphys/digestion/smallgut/index.html says "The net effect of passage through the small intestine is absorption of most of the water and electrolytes (sodium, chloride, potassium) and essentially all dietary organic molecules (including glucose, amino acids and fatty acids). Through these activities, the small intestine not only provides nutrients to the body, but plays a critical role in water and acid-base balance"   Danny289 Member 2+ Year Member Joined: I just took a kaplan exam and a question says "Water absorption occurs primarily in the A. duodenum. D. large intestine. E. mouth." explanation says "The large intestine is primarily involved in water reabsorption" and the answer is D. But I think small intestine absorb water. My class note says most of water is actually absorbed in small intestine. What large intestine absorbs is basically left-over water that small intestine couldn't finish absorbing. I am confused. large intestine is the answer. pay attention to the word"primarily" and again open your textbook.   joonkimdds Senior Member 7+ Year Member Joined: large intestine is the answer. pay attention to the word"primarily" and again open your textbook. Click to expand... If we say both small and large intestine absorb water, doesn't it make small intestine primary since water passes small first and reaches large?   Pre-Dental joonkimdds said: ↑ If we say both small and large intestine absorb water, doesn't it make small intestine primary since water passes small first and reaches large? Click to expand... In this case, primarily doesn't mean in order of sequence....it's used to describe the MAIN function....the small intestine's main function is to digest the incoming chyme and absorb the nutrients....of course it's going to absorb some water because the small intestine wall is not impermeable and is hyperosmotic to the blood....so yeah...hope that's the end of that...haha   I just took a kaplan exam and a question says "Water absorption occurs primarily in the A. duodenum. D. large intestine. E. mouth." explanation says "The large intestine is primarily involved in water reabsorption" and the answer is D. But I think small intestine absorb water. My class note says most of water is actually absorbed in small intestine. What large intestine absorbs is basically left-over water that small intestine couldn't finish absorbing. I am confused. Click to expand... You have to reword the question to find out what it is really asking. Another way of looking at it is "what is the primary function of each of these parts...which organ's primary function is to absorb water?" From wiki: In mammals, the small intestine is the part of the gastrointestinal tract (gut) following the stomach, and is where the vast majority of digestion takes place. The large intestine is the last part of the digestive system in vertebrate animals. Its function is to absorb water from the remaining indigestible food matter, and then to pass this useless waste material from the body.   D. large intestine. E. mouth." explanation says "The large intestine is primarily involved in water reabsorption" and the answer is D. But I think small intestine absorb water. My class note says most of water is actually absorbed in small intestine. What large intestine absorbs is basically left-over water that small intestine couldn't finish absorbing. I am confused. Click to expand... The answer choices are Duodenum and jejunum. These are part of the small intestine, not the entire intestine. It consists of duodenum, jejunum and illeum - all function in digestion. Since small intestine was not a choice, large intestine as a whole would be a better choice.  

i don't know

What is the colored muscle that responds involuntarily to light?

Pupil: Light, Perception & Life Science Activity | Exploratorium Teacher Institute Project None needed. To Do and Notice Place the magnifying glass on the surface of the mirror. Look into the center of the magnifying glass with one eye. If you wear contact lenses or glasses, you may either leave them on or remove them. Adjust your distance from the mirror until you see a sharply focused and enlarged image of your eye. You may need to adjust the position of the magnifier to get the clearest image of your eye. Notice the white of your eye, the colored disk of your iris, and your pupil, the black hole in the center of your iris. Shine a light into the pupil of one eye. If you are using a small mirror, hold the flashlight behind the mirror and shine the light around the edge of the mirror into your eye. If you are using a large mirror, bounce the flashlight beam off the mirror into your eye. Observe how your pupil changes size. Notice that it takes longer for your pupil to dilate than it does to contract. Notice also that the pupil sometimes overshoots its mark. You can see it shrink down too far, and then reopen slightly. Observe changes in the size of one pupil while you, or a partner, shine a light into and away from the other eye. In a dimly lit room, open and close one eye while observing the pupil of the other eye in the mirror. What's Going On? The pupil is an opening that lets light into your eye. Since most of the light entering your eye does not escape, your pupil appears black. In dim light, your pupil expands to allow more light to enter your eye. In bright light, it contracts. Your pupil can range in diameter from 1/16 inch (1.5 mm) to more than 1/3 inch (8 mm). Light detected by the retina of your eye is converted to nerve impulses that travel down the optic nerve. Some of these nerve impulses go from the optic nerve to the muscles that control the size of the pupil. More light creates more impulses, causing the muscles to close the pupil. Part of the optic nerve from one eye crosses over and couples to the muscles that control the pupil size of the other eye. That’s why the pupil of one eye can change when you shine the light into your other eye. In this experiment, the light reflecting from your eye passes through the magnifying lens twice—once on its way to the mirror and once on its way back. Therefore, the image of your eye is magnified twice by the magnifying glass. Going Further The size of your pupils actually reflects the state of your body and mind. Pupil size can change because you are fearful, angry, in pain, in love, or under the influence of drugs. Not only does the pupil react to emotional stimuli, it is itself an emotional stimulus. The size of a person’s pupils can give another person a strong impression of sympathy or hostility. The response of the pupil is an involuntary reflex. Like the knee-jerk reflex, the pupillary response is used to test the functions of people who might be ill or injured. You may have seen a doctor shine light into the eyes of a person with a suspected head injury—they are looking at the pupillary response. The pupil of your eye is also the source of the red eyes you sometimes see in flash photographs. When the bright light of a camera flash shines directly through the pupil, it can reflect off the choroid, which supplies red blood to the retina (the light-sensitive lining at the back of your eye), and bounce right back out through the pupil. If this happens, the person in the photograph will appear to have glowing red eyes. To avoid this, photographers move the flash away from the camera lens. With this arrangement, the light from the flash goes through the pupil at an angle, illuminating a part of the retina not captured by the camera lens. Many cameras are equipped with red-eye reduction features, such as a pre-flash that causes pupil constriction before the actual flash that illuminates the photo. Related Snacks

Iris

What is the name of the enzyme produced in the mouth?

Ocular Motor System (Section 3, Chapter 7) Neuroscience Online: An Electronic Textbook for the Neurosciences | Department of Neurobiology and Anatomy - The University of Texas Medical School at Houston Valentin Dragoi, Ph.D. , Department of Neurobiology and Anatomy , The UT Medical School at Houston 7.1 Introduction The simplicity of the motor systems involved in controlling eye musculature make them ideal for illustrating the mechanisms and principals you have been studying in the preceding material on motor systems. They involve the action of few muscles and of well defined neural circuits. We use our eyes to monitor our external environment and depend on our ocular motor systems to protect and guide our eyes. The ocular motor systems control eye lid closure, the amount of light that enters the eye, the refractive properties of the eye, and eye movements. The visual system provides afferent input to ocular motor circuits that use visual stimuli to initiate and guide the motor responses. Neuromuscular systems control the muscles within the eye (intraocular muscles); the muscles attached to the eye (extraocular muscles) and the muscles in the eyelid. Ocular motor responses include ocular reflexes and voluntary motor responses to visual and other stimuli. The complexity of the circuitry (the chain or network of neurons) controlling a ocular motor response increases with the level of processing involved in initiating, monitoring, and guiding the response. In this chapter we will start at the level of reflex responses and move onto more complex voluntary responses in the following lecture. The eye blink reflex is the simplest response and does not require the involvement of cortical structures. In contrast, voluntary eye movements (i.e., visual tracking of a moving object) involve multiple areas of the cerebral cortex as well as basal ganglion, brain stem and cerebellar structures. 7.2 Ocular Reflex Responses The ocular reflexes are the simplest ocular motor responses. Ocular reflexes compensate for the condition of the cornea and for changes in the visual stimulus. For example, the eye blink reflex protects the cornea from drying out and from contact with foreign objects. The pupillary light reflex compensates for changes in illumination level, whereas the accommodation responses compensate for changes in eye-to-object-viewed distance. Note that reflex responses are initiated by sensory stimuli that activate afferent neurons (e.g., somatosensory stimuli for the eye blink reflex and visual stimuli for the pupillary light reflex and accommodation responses). In general, ocular reflexes are consensual (i.e., the response is bilateral involving both eyes). Consequently, a light directed in one eye elicits responses, pupillary constriction, in both eyes. In this chapter you will learn of the structures normally involved in performing these ocular responses and the disorders that result from damage to components of neural circuit controlling these responses. A. The Eye Blink Reflex Tactile stimulation of the cornea results in an irritating sensation that normally evokes eyelid closure (an eye blink). The response is consensual (i.e., bilateral) - involving automatic eyelid closure at both eyes. The corneal eye blink reflex neural circuit: This neural circuit (Figure 7.1) is relatively simple, consisting of the trigeminal1° afferent (free nerve endings in the cornea, trigeminal nerve, ganglion, root, and spinal trigeminal tract), which end on trigeminal 2° afferent in the spinal trigeminal nucleus, some of which send their axons to reticular formation interneurons, which send their axons bilaterally to facial motor neurons in the facial nucleus, which send their axons in the facial nerve to orbicularis oculi, which functions to lower the eyelid Figure 7.1 The corneal eye blink reflex is initiated by the free nerve endings in the cornea and involves the trigeminal nerve and ganglion, the spinal trigeminal tract and nucleus, interneurons in the reticular formation, motor neurons in the facial nucleus and nerve, and the orbicularis oculi. As the afferent information from each cornea is distributed bilaterally to facial motor neurons by the reticular formation interneurons, the eye blink response is consensual, that is, both eye lids will close to stimulation of the cornea of either eye. B. Pupillary Light Reflex The pupillary light reflex involves adjustments in pupil size with changes in light levels. The reflex is consensual: Normally light that is directed in one eye produces pupil constriction in both eyes. The direct response is the change in pupil size in the eye to which the light is directed (e.g., if the light is shone in the right eye, the right pupil constricts). The consensual response is the change in pupil size in the eye opposite to the eye to which the light is directed (e.g., if the light is shone in the right eye, the left pupil also constricts consensually). The pupillary light reflex allows the eye to adjust the amount of light reaching the retina and protects the photoreceptors from bright lights. The iris contains two sets of smooth muscles that control the size of the pupil (Figure 7.2). The sphincter muscle fibers form a ring at the pupil margin so that when the sphincter contracts, it decreases (constricts) pupil size. The dilator muscle fibers radiate from the pupil aperture so that when the dilator contracts, it increases (dilates) pupil size. Both muscles act to control the amount of light entering the eye and the depth of field of the eye 1 . The iris sphincter is controlled by the parasympathetic system, whereas the iris dilator is controlled by the sympathetic system. The action of the dilator is antagonistic to that of the sphincter and the dilator must relax to allow the sphincter to decrease pupil size. Normally the sphincter action dominates during the pupillary light reflex. Figure 7.2 Iris dilator and sphincter muscles and their actions. The pupillary light reflex neural circuit: The pathway controlling pupillary light reflex (Figure 7.3) involves the retina, optic nerve, optic chiasm, and the optic tract fibers that join the brachium of the superior colliculus, which terminate in the pretectal area of the midbrain, which sends most of its axons bilaterally in the posterior commissure to terminate in the Edinger-Westphal nucleus of the oculomotor complex, which contains parasympathetic preganglionic neurons and sends its axons in the oculomotor nerve to terminate in the ciliary ganglion, which sends its parasympathetic postganglionic axons in the short ciliary nerve, which ends on the iris sphincter Figure 7.3 The pupillary light reflex pathway. The lines ending with an arrow indicate axons terminating in the structure at the tip of the arrow. The lines beginning with a dot indicate axons originating in the structure containing the dot. Bilateral damage to pretectal area neurons (e.g., in neurosyphilis) will produce Argyll-Robertson pupils (non-reactive to light, active during accommodation). Recall that the optic tract carries visual information from both eyes and the pretectal area projects bilaterally to both Edinger-Westphal nuclei: Consequently, the normal pupillary response to light is consensual. That is, a light directed in one eye results in constriction of the pupils of both eyes. C. Pupillary Dark Response The pupils normally dilate (increase in size) when it is dark (i.e., when light is removed). This response involves the relaxation of the iris sphincter and contraction of the iris dilator. The iris dilator is controlled by the sympathetic nervous system. The pupillary dark reflex neural circuit: The pathway controlling pupil dilation involves the retina and the optic tract fibers terminating on neurons in the hypothalamus and the axons of the hypothalamic neurons that descend to the spinal cord to end on the sympathetic preganglionic neurons in the lateral horn of spinal cord segments T1 to T3, which send their axons out the spinal cord to end on the sympathetic neurons in the superior cervical ganglion, which send their sympathetic postganglionic axons in the long ciliary nerve to the iris dilator. Axons from the superior cervical ganglion also innervate the face vasculature, sweat and lachrymal glands and the eyelid tarsal muscles. When the superior cervical ganglion or its axons are damaged, a constellation of symptoms, known as Horner's syndrome, result. This syndrome is characterized by miosis (pupil constriction), anhidrosis (loss of sweating), pseudoptosis (mild eyelid droop), enopthalmosis (sunken eye) and flushing of the face. D. The Accommodation Response The accommodation response is elicited when the viewer directs his eyes from a distant (greater than 30 ft. away) object to a nearby object (Nolte, Figure 17-40, Pg. 447). The stimulus is an “out-of-focus” image. The accommodation (near point) response is consensual (i.e., it involves the actions of the muscles of both eyes). The accommodation response involves three actions: Pupil accommodation: The action of the iris sphincter was covered in the section on the pupillary light reflex. During accommodation, pupil constriction utilizes the "pin-hole" effect and increases the depth of focus of the eye by blocking the light scattered by the periphery of the cornea (Nolte, Figure 17-39, Pg. 447). The iris sphincter is innervated by the postganglionic parasympathetic axons (short ciliary nerve fibers) of the ciliary ganglion (Figure 7.3). Lens accommodation: Lens accommodation increases the curvature of the lens, which increases its refractive (focusing) power. The ciliary muscles are responsible for the lens accommodation response. They control the tension on the zonules, which are attached to the elastic lens capsule at one end and anchored to the ciliary body at the other end (Figure 7.4). Figure 7.4 The ciliary muscles, which control the position of the ciliary processes and the tension on the zonule, control the shape of the lens. The ciliary muscles function as a sphincter and when contracted pull the ciliary body toward the lens to decrease tension on the zonules (see Figure 7.5). The decreased tension allows the lens to increase its curvature and refractive (focusing) power. When the ciliary muscle is relaxed, the ciliary body is not pulled toward the lens, and the tension on the zonules is higher. High tension on the zonules pulls radially on the lens capsule and flattens the lens for distance vision. The ciliary muscles are innervated by the postganglionic parasympathetic axons (short ciliary nerve fibers) of the ciliary ganglion Figure 7.5 The accommodation response of the lens: comparing the lens shape during near vision (contraction of the ciliary muscle during accommodation) with lens shape during distance vision (relaxation of the ciliary muscle). Convergence in accommodation: When shifting one's view from a distant object to a nearby object, the eyes converge (are directed nasally) to keep the object's image focused on the foveae of the two eyes. This action involves the contraction of the medial rectus muscles of the two eyes and relaxation of the lateral rectus muscles. The medial rectus attaches to the medial aspect of the eye and its contraction directs the eye nasally (adducts the eye). The medial rectus is innervated by motor neurons in the oculomotor nucleus and nerve. The accommodation neural circuit: The circuitry of the accommodation response is more complex than that of the pupillary light reflex (Figure 7.6). The afferent limb of the circuit includes the retina (with the retinal ganglion axons in the optic nerve, chiasm and tract), lateral geniculate body (with axons in the optic radiations), and visual cortex. Ocular motor control neurons are interposed between the afferent and efferent limbs of this circuit and include the visual association cortex, which determines the image is "out-of-focus" sends corrective signals via the internal capsule and crus cerebri to the supraoculomotor nuclei, which is located immediately superior to the oculomotor nuclei generates motor control signals that initiate the accommodation response sends these control signals bilaterally to the oculomotor complex. The efferent limb of this system has two components: the Edinger-Westphal nucleus, which sends its axons in the oculomotor nerve to control the ciliary ganglion, which sends it axons in the short ciliary nerve to control the iris sphincter and the ciliary muscle/zonules/lens of the eye oculomotor neurons, which sends its axons in the oculomotor nerve to control the medial rectus converge the two eyes. Figure 7.6 The accommodation pathway includes the afferent limb, which consists of the entire visual pathway; the higher motor control structures, which includes an area in the visual association cortex and the supraoculomotor area; and the efferent limb, which includes the oculomotor nuclei and ciliary ganglion. The lines ending with an arrow indicate axons terminating in the structure at the tip of the arrow. The lines beginning with a dot indicate axons originating in the structure containing the dot. During accommodation three motor responses occur: convergence (medial rectus contracts to direct the eye nasally), pupil constriction (iris sphincter contracts to decrease the iris aperture) and lens accommodation (ciliary muscles contract to decrease tension on the zonules). 7.3 Clinical Examples An excellent way to test your knowledge of the material presented thus far is by examining the effects of damage to structures within the ocular motor pathways. The observed motor loss(s) provide clues to the pathway(s) affected; and the muscle(s) and eye affected provide clues to the level of the damage. Cranial nerve damage: Damage to cranial nerves may result in sensory and motor symptoms. The sensory losses would involve those sensations the cranial nerve normally conveys (e.g., taste from the anterior two thirds of the tongue and somatic sensations from the skin of the ear - if facial nerve is damaged). The motor losses may be severe (i.e., a lower motor neuron loss that produces total paralysis) if the cranial nerve contains all of the motor axons controlling the muscles of the normally innervated area. The cranial nerves involved in the eye blink response and pupillary response are the optic, oculomotor, trigeminal and facial nerves. The optic nerve carries visual information from the eye. The oculomotor nerve contains extraocular muscles: the medial, superior and inferior rectus muscles, the inferior oblique muscle, eyelid muscle: the superior levator palpebrae, as well as parasympathetic preganglionic axons to the ciliary ganglion. The trigeminal nerve contains the 1° somatosensory afferents for the face, dura, oral and nasal cavities the lower motor axons for the jaw muscles. The facial nerve contains Observe the reaction to a wisp of cotton touching the patient's left and right cornea. Observation: You observe that the patient has not lost cutaneous sensation in the upper left face area does not blink when his left cornea is touched cannot close his left eye voluntarily You conclude that his left eye's functional loss is not sensory a lower motor neuron dysfunction Pathway(s) affected: You conclude that structures in the following motor pathway have been affected the eye blink pathway (Figure 7.8) Figure 7.8 The eye blink pathway involves the trigeminal nerve, spinal trigeminal tract and nucleus, the reticular formation, and the facial motor nucleus and nerve. Side & Level of damage: As the eye blink loss involves only motor function Observe the reaction to a wisp of cotton touching the patient's left and right cornea. Observation: You observe that the patient responds with direct and consensual eye blink when his right cornea is touched can close his left eye voluntarily has lost cutaneous sensation in the upper left face area does not blink when his left cornea is touched You conclude that his left eye's functional loss is not motor Pathway(s) affected: You conclude that structures in the following reflex pathway have been affected the eye blink pathway (Figure 7.8) Side & Level of damage: As the eye blink loss involves only one eye the upper part of the face Conclusion: You conclude that the damage involves a loss of the afferent limb of the eye blink response the trigeminal nerve a branch of the nerve innervating the upper face the innervation of the left side (i.e., the symptoms are ipsilesional) The Trigeminal Nerve. Section of the trigeminal nerve will eliminate somatosensory sensation from the face and the eye blink reflex (e.g., with section of the left trigeminal nerve, light touch of the left cornea will not produce an eye blink in the left or right eye). However, light touch of the right cornea will elicit a bilateral eye blink. The effect of sectioning the trigeminal nerve is to remove the afferent input for the eye blink reflex. 7.6 Clinical Example #3 Symptoms. The patient complains of pain in her left eye. Her left pupil appears dilated and is not reactive to light directed at either the left or right eye (Figure 7.10). The right pupil appears normal in size and reacts to light when it is directed in the right or left eye. Both eyelids can be elevated and lowered and both eyes exhibit normal movement. Touch, vibration, position and pain sensations are normal over the entire the body and face. There are no other motor symptoms. Figure 7.10 Observe the reaction of the patient's pupils to light directed in the left or right eye. Observation: You observe that the patient has a left pupil that does not react to light directly or consensually a right pupil that reacts to light directly and consensually normal eye movements You conclude that his left eye's functional loss is not sensory (the right pupil reacts to light directed at the left eye) a motor dysfunction Pathway(s) affected: You conclude that structures in the following motor pathway have been affected the pupillary light reflex pathway (Figure 7.11) Figure 7.11 The pupillary light reflex pathway involves the optic nerve and the oculomotor nerve and nuclei. Side & Level of damage: As the pupillary light reflex loss involves only one eye Observe the reaction of the patient's pupils to light directed in the left or right eye. Observation: You observe that the patient's pupils respond when light is directed into either eye has weaker direct and consensual responses to light directed in the left eye You conclude that his left eye's functional loss is not motor sensory (because the responses in both eyes are weaker when light is directed in the left eye) Pathway(s) affected: You conclude that structures in the following motor pathway have been affected the pupillary light reflex pathway (Figure 7.11) Side & Level of damage: As the pupillary light response deficit involves only stimulation of one eye a sensory loss Conclusion: You conclude that the damage is in the afferent limb of the pupillary light response involves the optic nerve or retina is on the left side (i.e., the symptoms are ipsilesional) produced a left pupillary afferent defect The Optic Nerve. Partial damage of the retina or optic nerve reduces the afferent component of the pupillary reflex circuit. The reduced afferent input to the pretectal areas is reflected in weakened direct and consensual pupillary reflex responses in both eyes (a.k.a., a relative afferent pupillary defect). Section of one optic nerve will result in the complete loss of the direct pupillary light reflex but not the consensual reflex of the blinded eye. That is, if the left optic nerve is sectioned, light directed on the left (blind) eye will not elicit a pupillary response in the left eye (direct reflex) or the right eye (consensual response). However, light directed in the right eye will elicit pupillary responses in the right eye and the left (blind) eye. The effect of sectioning one optic nerve is to remove the afferent input for the direct reflex of the blinded eye and the afferent input for the consensual reflex of the normal eye. Section of one optic tract will not eliminate the direct or consensual reflex of either eye as the surviving optic tract contains optic nerve fibers from both eyes. However, the responses to light in both eyes may be weaker because of the reduced afferent input to the ipsilesional pretectal area. 7.9 Clinical Example #6 Symptoms. A patient who is suffering from the late stages of syphilis is sent to you for a neuro-ophthalmological work-up. His vision is normal when corrected for refractive errors. He has normal ocular mobility and his eyelids can be elevated and depressed at will. Examination of his pupillary responses indicates a loss of the pupillary light reflex (no pupil constriction to light in either eye) but normal pupillary accommodation response (pupil constricts when the patient's eyes are directed from a distant object to one nearby). Observation: You observe that the patient has normal vision but that his pupils do not respond when light is directed into the either of his eyes do respond during accommodation You conclude that his eye's functional loss is not sensory (his vision is normal) motor (the pupillary light responses in both eyes are absent) higher-order motor (because he has a normal pupillary accommodation response) Pathway(s) affected: You conclude that structure(s) in the accommodation pathway have not been damaged (Figure 7.14) pupillary light reflex pathway have been damaged (Figure 7.11) Side & Level of damage: As the pupillary response deficit does not involve a sensory loss does not involve the pupil accommodation response involves only the pupillary light reflex response Conclusion: You conclude that the damage involves the pretectal area bilaterally spared the supraoculomotor area produced the Argyll Robertson response Figure 7.14 The accommodation pathway includes the supraoculomotor area, which functions as a "higher-order" motor control stage controlling the motor neurons and parasympathetic neurons (i.e., the Edinger-Westphal neurons) of the oculomotor nucleus. This area was spared by syphilis. In the Argyll Robertson response, there is an absence of the pupillary light reflex with a normal pupillary accommodation response. The Argyll Robertson response is attributed to bilateral damage to pretectal areas (which control the pupillary light reflex) with sparing of the supraoculomotor area (which controls the pupillary accommodation reflex). The accommodation response involves many of the structures involved in the pupillary light response and, with the exception of the pretectal area and supraoculomotor area, damage to either pathway will produce common the symptoms. The most common complaint involving the accommodation response is its loss with aging (i.e., presbyopia). Recall that presbyopia most commonly results from structural changes in the lens which impedes the lens accommodation response. 7.10 Summary This chapter described three types of ocular motor responses (the eye blink, pupillary light and accommodation responses) and reviewed the nature of the responses and the effectors, efferent neurons, higher-order motor control neurons (if any), and afferent neurons normally involved in performing these ocular responses. Table I summarizes these structures and the function(s) of these ocular motor responses. Readers should understand the anatomical basis for disorders that result from damage to components of neural circuit controlling these responses. Table I

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The pituitary controls many hormones, but what controls the pituitary?

You & Your Hormones | Glands | Pituitary gland You & Your Hormones   Email article to a friend | Last updated: January 21, 2015 The pituitary gland is a small pea-sized gland that plays a major role in regulating vital body functions and general wellbeing. It is referred to as the body’s ‘master gland’ because it controls the activity of most other hormone-secreting glands. Computer artwork of a person's head showing the left hemisphere of the brain inside. The highlighted area (centre) shows the pituitary gland attached to the bottom of the hypothalamus at the base of the brain. Alternative names Hypophysis. Where is my pituitary gland? The pituitary gland is a pea-sized gland. It sits in the sella turcica (‘Turkish saddle’), a bony hollow in the base of the skull, underneath the brain and behind the bridge of the nose. Although the pituitary gland looks like one gland, it actually has two distinct parts, the anterior pituitary gland and the posterior pituitary gland. The gland is attached to the hypothalamus , the part of the brain that controls its activity. The anterior part of the pituitary gland consists of gland cells, which are connected to the brain by very short blood vessels. The posterior pituitary gland is actually part of the brain and it secretes hormones directly into the bloodstream under the command of the brain.  What does my pituitary gland do? The pituitary gland is called the ‘master gland’ as the hormones it produces control so many different processes in the body. It senses the body’s needs and sends signals to different organs and glands throughout the body to regulate their function and maintain an appropriate environment. It secretes a variety of hormones into the bloodstream which act as messengers to transmit information from the pituitary gland to distant cells, regulating their activity. For example, the pituitary gland produces prolactin , which acts on the breasts to induce milk production. The pituitary gland also secretes hormones that act on the adrenal glands , thyroid gland , ovaries and testes , which in turn produce other hormones. Through production of its hormones, the pituitary gland controls metabolism , growth, sexual maturation, reproduction, blood pressure and many other vital physical functions and processes. What hormones does my pituitary gland produce? The anterior pituitary gland produces the following hormones and releases them into the bloodstream: Adrenocorticotropic hormone , which stimulates the adrenal glands to secrete steroid hormones, principally cortisol   Thyroid stimulating hormone , which stimulates the thyroid gland to secrete thyroid hormones. There are also some hormones that are produced by the hypothalamus and then stored in the posterior pituitary gland prior to being released into the bloodstream. These are: Anti-diuretic hormone , which controls water balance and blood pressure. It is made by the hypothalamus but is stored in the posterior pituitary gland prior to being released into the bloodstream.   Oxytocin , which stimulates uterine contractions during labour and milk secretion during breastfeeding. It is made by the hypothalamus but is stored in the posterior pituitary gland prior to being released into the bloodstream. Each of these hormones is made by a separate type of cell within the pituitary gland, except for follicle stimulating hormone and luteinising hormone, which are made together by the same cell.  What could go wrong with my pituitary gland? The pituitary gland is an important gland in the body and the hormones it produces carry out varied tasks and regulate the function of many other organs. This means that the symptoms experienced when the pituitary gland stops working correctly can be varied depending on which hormone is affected.    Conditions that affect the pituitary gland directly can be divided into three main categories: Conditions that cause the pituitary gland to produce too much of one or more hormone(s). Examples include acromegaly , Cushing's disease and prolactinoma .   Conditions that cause the pituitary gland to produce too little of one or more hormone(s). Examples include adult growth hormone deficiency , diabetes insipidus or hypopituitarism .   Conditions that alter the size and/or shape of the pituitary gland. Examples include empty sella syndrome . A cell type may divide and then form a small benign lump known as a tumour, and the patient may then suffer from the effects of too much of the hormone the cell produces. If the tumour grows very large, even though still benign, it may squash the surrounding cells and stop them working (hypopituitarism), or push upwards and interfere with vision – a visual field defect. Very occasionally, the tumour may expand sideways and cause double vision as it affects the nerves which control eye movements. It should be emphasised that even when these tumours are large, they usually remain quite benign and very rarely spread to other parts of the body.  

Hypothalamus

What is the pigment that colors skin?

Pituitary Tumor: Frequently Asked Questions - Health Encyclopedia - University of Rochester Medical Center Pituitary Tumor: Frequently Asked Questions Location of the Pituitary Gland What is the pituitary gland? The pituitary gland is a small gland located inside the skull, just below the brain. It is behind the nasal sinuses and above the roof of the mouth. The pituitary gland connects to a part of the brain called the hypothalamus. Together, the hypothalamus and the pituitary control the body’s production of many important hormones. The pituitary gland sits in a tight, bony space. It has little room to grow or expand when swollen, or if there is a tumor. The pituitary gland controls most of the body’s gland activity. This includes the adrenal and thyroid glands. It also includes sex hormone production. In women, it controls egg production (ovulation). In men, it controls testosterone and sperm production in the testicles. It is also believed to be the main control gland of the body’s neuroendocrine system. The pituitary gland has 2 parts: the back part (posterior pituitary) and the front part (anterior pituitary). The back part makes the following hormones: Vasopressin, also called ADH (antidiuretic hormone). This hormone lets the kidneys keep healthy amounts of water and not send it all out in urine. It can also raise blood pressure by causing blood vessels to narrow or tighten. Oxytocin. This female hormone helps the uterus contract during childbirth. It also helps the breasts release milk when a woman is nursing. The front part of the pituitary makes several kinds of hormones. These hormones control other glands all over the body: Growth hormone (somatotropin). This hormone helps a child's body grow, especially during the teen years (puberty). Adults don’t normally make a lot of this hormone. Thyroid-stimulating hormone (TSH or thyrotropin). This hormone helps the thyroid gland to grow, and to make and release the thyroid hormone. The thyroid hormone controls how your body turns food into energy (metabolism). Adrenocorticotropic hormone (ACTH). This hormone stimulates the adrenal gland so that it can make certain steroid hormones. Luteinizing hormone (LH) and follicle-stimulating hormone (FSH), also called gonadotropins. In women, these hormones control the menstrual cycle ovulation. In men, they control testosterone and sperm production. Prolactin. This hormone helps make milk in a woman’s breast. It’s not clear how it works in men. What are pituitary tumors? A pituitary tumor is a tumor that begins in the pituitary gland. Most pituitary tumors are not cancer. Cancerous pituitary tumors are very rare. They are so rare that cancer agencies don’t keep track of how many people get them each year. Noncancerous (benign) pituitary tumors are also rare. About 10,000 people in the U.S. get them each year. What are adenomas? There are different kinds of pituitary tumors. Most of these tumors are not cancer. They are called adenomas. They don’t usually spread outside the pituitary gland. But they can greatly affect your health. They can push on nearby parts of the brain. And they may send out excess hormones. Pituitary adenomas are grouped in 2 ways: by their size and by the kind of hormone they make. Size. Pituitary adenomas are grouped into 2 sizes: Microadenomas are tumors that are smaller than 1 centimeter (cm). Macroadenomas are tumors that are bigger than 1 cm. Both kinds of tumors can either make hormones (functional) or not make hormones (nonfunctional). Most pituitary tumors are functional. This means they make excess hormones. Hormones. Pituitary adenomas are also grouped by whether they make excess hormones. Those that do are called functional. They are then grouped by the type of hormone they make. Functional adenomas include tumors that: Make prolactin Make gonadotropin (LH and FSH) Make thyroid-stimulating hormone (TSH and thyrotropin) Some tumors make more than 1 type of hormone. A pituitary adenoma that doesn’t make excess hormones is called nonfunctional. What are the risk factors for pituitary tumors? Certain factors can make 1 person more likely to get a pituitary tumor than another person. These are called risk factors. Doctors are not sure exactly what causes pituitary tumors. Most people who get a pituitary tumor have no known risk factors. The only proven risk factor for a pituitary tumor is a rare condition called MEN1 (multiple endocrine neoplasia, type 1). MEN1 syndrome is hereditary. This means it is passed down from parent to child. People with MEN1 have a high risk of getting tumors of the pituitary, the parathyroid, and the pancreas. If a parent carries the gene change for this rare syndrome, the child has a 50% change of getting MEN1. What are the symptoms of pituitary tumors? Both noncancer and cancerous pituitary tumors can cause symptoms. These may include: Double or blurred vision

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Which tissue secretes progesterone during the second half of the menstrual cycle?

You & Your Hormones | Hormones | Progesterone You & Your Hormones   Email article to a friend | Last updated: January 14, 2015 Progesterone is a hormone released by the corpus luteum in the ovary. It plays important roles in the menstrual cycle and in maintaining the early stages of pregnancy. It may also be involved in the growth of certain cancers. What is progesterone? Progesterone belongs to a group of steroid hormones called progestogens . It is mainly secreted by the corpus luteum in the ovary during the second half of the menstrual cycle.  It plays important roles in the menstrual cycle and in maintaining the early stages of pregnancy. During the menstrual cycle, when an egg is released from the ovary at ovulation (approximately day 14), the remnants of the ovarian follicle that enclosed the developing egg form a structure called the corpus luteum. This releases progesterone and, to a lesser extent, oestradiol . The progesterone prepares the body for pregnancy in the event that the released egg is fertilised. If the egg is not fertilised, the corpus luteum breaks down, the production of progesterone falls and a new menstrual cycle begins. If the egg is fertilised, progesterone stimulates the growth of blood vessels that supply the lining of the womb (endometrium) and stimulates glands in the endometrium to secrete nutrients that nourish the early embryo. Progesterone then prepares the tissue lining of the uterus to allow the fertilised egg to implant and helps to maintain the endometrium throughout pregnancy. During the early stages of pregnancy, progesterone is still produced by the corpus luteum and is essential for supporting the pregnancy and establishing the placenta . Once the placenta is established, it then takes over progesterone production at around week 12 of pregnancy. During pregnancy, progesterone plays an important role in the development of the foetus; stimulates the growth of maternal breast tissue; prevents lactation; and strengthens the pelvic wall muscles in preparation for labour . The level of progesterone in the body steadily rises throughout pregnancy until labour occurs and the baby is born. Although the corpus luteum in the ovaries is the major site of progesterone production in humans, progesterone is also produced in smaller quantities by the ovaries themselves, the adrenal glands and, during pregnancy, the placenta. How is progesterone controlled? The formation of the corpus luteum (which produces the majority of progesterone) is triggered by a surge in luteinising hormone production by the anterior pituitary gland . This normally occurs at approximately day 14 of the menstrual cycle and it stimulates the release of an egg from the ovary and the formation of the corpus luteum. The corpus luteum then releases progesterone which prepares the body for pregnancy. If the egg is not fertilised and no embryo is conceived, the corpus luteum breaks down and the production of progesterone decreases. As the lining of the womb is no longer maintained by progesterone from the corpus luteum, it breaks away and menstrual bleeding occurs, marking the start of a new menstrual cycle. However, if the ovulated egg is fertilised and gives rise to an embryo, the cells that surround this early embryo (which are destined to form the placenta) will secrete human chorionic gonadotrophin . This hormone has a very similar chemical structure to luteinising hormone. This means it can bind to and activate the same receptors as luteinising hormone, meaning that the corpus luteum does not break down and instead keeps producing progesterone until the placenta is established.  What happens if I have too much progesterone? There are no known serious medical consequences of having too much progesterone. Levels of progesterone do increase naturally in pregnancy as mentioned above. High levels of progesterone are associated with the condition congenital adrenal hyperplasia . However, the high progesterone levels are a consequence of and not a cause of this condition. Also, high levels of progesterone are associated with an increased risk for developing breast cancer. Progesterone, either alone or in combination with oestrogen , is taken by women as an oral contraceptive (‘the pill’). ‘The pill’ works by preventing ovulation, making it nearly 100% effective in preventing pregnancy. Progesterone is used in hormone replacement therapy to relieve symptoms of the menopause in women. There are many recognised pros and cons to hormone replacement therapy – see the article on ‘ What is HRT ?’ for more information. What happens if I have too little progesterone? If progesterone is absent or levels are too low, irregular and heavy menstrual bleeding can occur. A drop in progesterone during pregnancy can result in a miscarriage and early labour. Mothers at risk of giving birth too soon can be given a synthetic form of progesterone to delay the onset of labour.  Lack of progesterone in the bloodstream can mean the ovary has failed to release an egg at ovulation, as can occur in women with polycystic ovary syndrome .  

Corpus luteum

Which gland secretes the corticosteroids?

Progesterone Misconceptions – Life Extension April 2006 By Dr. Sergey Dzugan and Armond Scipione Two recent studies of progesterone supplementation validate what the Life Extension Foundation has contended for the past 12 years: restoring the body’s supply of natural progesterone confers multiple health benefits, including balancing blood sugar levels, promoting normal sleep, reducing anxiety, and stimulating new bone growth.1,2 Controlled studies and most observational studies published in the last five years suggest that the addition of progestins (synthetic progesterone) to hormone replacement therapy, particularly in a continuous combined regimen, increases the risk of breast cancer compared to estrogen alone.1 While the results of clinical trials may accurately assess the risks associated with synthetic progestin compounds and estrogen/ progestin combinations, the data do not reflect what might have been the result had natural progesterone been used instead of synthetic progesterone.2 Recent studies suggest that the addition of natural progesterone in a cyclic manner does not increase breast cancer risk. These findings are consistent with in-vivo data suggesting that progesterone does not have a detrimental effect on breast tissue.1 Estrogen and Progesterone Levels During a 28-day Menstrual Cycle Nature has given progesterone to men and women alike to balance and offset the powerful effects of estrogen. Some of the most common concerns of aging women are weight gain, insomnia, anxiety, depression, and migraine. For other women, even more debilitating conditions such as cancer, uterine fibroids, ovarian cysts, and osteoporosis now play a predominant role in their lives. As men age, complaints of weight gain, loss of libido, and prostate enlargement top their list of health concerns. Many physicians and scientists are becoming more aware of a common link between these symptoms and conditions. That common link is often an imbalance between two sex hormones, progesterone and estrogen. In menstruating women, progesterone is one of two primary sex hormones (the other being estrogen) produced each month by the ovaries. During the first 14 days of the menstrual cycle, the ovaries secrete increasing amounts of estrogens. This two-week period is named the follicular phase. Halfway through a woman’s cycle, around day 14, one of her two ovaries will ovulate and release an egg. After ovulation, the ruptured follicle from which the egg has been released is transformed into the corpus luteum and begins producing progesterone. The portion of the menstrual cycle that follows ovulation, called the luteal phase, is orchestrated by progesterone. As its name implies, progesterone prepares (promotes) the womb for pregnancy (gestation). If the egg fails to be fertilized and no pregnancy occurs, the production of both progesterone and estrogen will rapidly decline, resulting in a period (menses). If pregnancy does occur, the placenta begins to secrete progesterone (the corpus luteum continues to produce progesterone as well). In fact, by the fifth month of pregnancy, the placenta itself secretes sufficient progesterone such that the corpus luteum is no longer essential to maintain pregnancy. These high levels of progesterone act as natural birth control agents, shutting down ovulation for the duration of the pregnancy. Plasma concentrations of progesterone in women vary throughout the menstrual cycle. During the follicular phase, plasma concentrations of progesterone are generally below 2 nanograms per milliliter (ng/mL). Throughout the luteal phase, which prepares the body for pregnancy, progesterone levels can rise to 28 ng/mL. Dramatic increases in progesterone occur throughout pregnancy: plasma levels may reach 40 ng/mL in the first trimester, and climb to 100-200 ng/mL near the delivery date.3 Progesterone is a key precursor to other steroid hormones, including cortisol, testosterone, and the estrogens (estriol, estradiol, and estrone). When progesterone circulates in the blood, 90% is bound to a protein or albumin fraction. Only a small percentage (3%) circulates unbound.4 While a woman’s estrogen may eventually drop 40-60% below her baseline level by menopause, her progesterone level can drop even more dramatically. Although the adrenal glands still produce some progesterone, the decline in progesterone upsets the body’s natural hormone balance. Following menopause, a woman’s progesterone level drops to nearly zero.  Actions of Progesterone Progesterone plays a key role in the tasks necessary for reproduction. Beyond preparation for pregnancy, progesterone has a multitude of effects throughout the body, many of which may be attributable to its ability to oppose the action of estrogen. Multiple physical and psychological problems at midlife are often caused by an imbalance between progesterone and estrogen. The term “estrogen dominance” describes the condition of lacking sufficient progesterone to counteract the effects of estrogen. A common misconception is that estrogen dominance results only from extremely high levels of estrogen. To the contrary, this condition also may be caused by normal levels of estrogen and relatively low levels of progesterone, or by low levels of estrogen and extremely low levels of progesterone. Estrogen levels may be elevated by a number of external influences. Xenoestrogens (foreign estrogens) are among a group of chemicals known to alter hormone levels. Environmental pesticides, including those found on commercially grown fruits and vegetables, are perhaps the primary source of xenoestrogens. Cosmetics, shampoo, and plastics also may contribute to the accumulation of these foreign estrogens. Progesterone’s many functions in the body include: maintaining the uterine lining and preventing excess tissue buildup inhibiting breast tissue overgrowth increasing metabolism and promoting weight loss balancing blood sugar levels acting as a natural diuretic normalizing blood clotting stimulating the production of new bone enhancing the action of thyroid hormones alleviating depression and reducing anxiety promoting normal sleep patterns restoring proper cell oxygen levels improving libido.5-16 Natural vs. Synthetic Progesterone When discussing progesterone, it is important to understand the difference between natural progesterone and the synthetic progesterone analogs called progestins. Progestogens is an umbrella term for both natural progesterone and the synthetic progestins, because they all have progestational effects in the uterus. Natural progesterone is synthesized in the laboratory from either soybeans or the Mexican wild yam (Dioscorea villosa). The process was discovered in the 1930s by Pennsylvania State University professor Russell Marker, who transformed diosgenin from wild yams into natural progesterone. Natural progesterone refers to bioidentical hormone products that have a molecular structure identical to the hormones our bodies manufacture naturally. The most effective form of bioidentical progesterone is called micronized progesterone USP. The process of micronization allows for steady and even absorption of the medication. Micronized progesterone is available only through a doctor’s prescription. An alternative is natural progesterone creams sold over the counter worldwide. Both the micronized progesterone and commercially available progesterone creams contain bioidentical progesterone. SYMPTOMS OF PROGESTERONE DEFICIENCY/IMBALANCE Decreased libido Heavy periods. Unlike progesterone, synthetic progestins are not molecularly identical to the hormones found naturally in the body. Synthetic progestins were first developed for use as contraceptive agents. Because the half-life of natural progesterone is very short, researchers sought an agent that would produce longer-lasting, more potent effects than natural progesterone. Birth control pills usually contain a synthetic progestin and a synthetic estrogen. Synthetic progestins are very potent, with just a small dose preventing ovulation and thus functioning as birth control. A slight change in the chemical structure of progesterone has allowed pharmaceutical companies to create patentable and profitable birth control products.

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What are the natural pain-killing substances produced in the brain and pituitary gland?

Endorphins | definition of endorphins by Medical dictionary Endorphins | definition of endorphins by Medical dictionary http://medical-dictionary.thefreedictionary.com/endorphins Related to endorphins: dopamine , serotonin en·dor·phins (en-dōr'finz, en'dōr-finz), Opioid peptides originally isolated from the brain but now found in many parts of the body; in the nervous system, endorphins bind to the same receptors that bind exogenous opiates. A variety of endorphins (for example, α, β, and γ) that vary not only in their physical and chemical properties but also in physiologic action have been isolated. [fr. endogenous morphine] endorphins A number of morphine-like peptide substances naturally produced in the body and for which morphine receptors exist in the brain. Many of these active substances have been found, all with the same opioid core of five amino acids. They are neurotransmitters and have a wide range of functions. They help to regulate heart action, general hormone function, the mechanisms of shock from blood loss and the perception of pain, and are probably involved in controlling mood, emotion and motivation. They are thought to be produced under various circumstances in which acute relief of pain or mental distress is required. At least some of the endorphins are produced by the PITUITARY gland as part of the precursor of the ACTH molecule. Endorphins are fragments cleaved from the beta-lipotropin component of proopiomelanocortin ( POMC ). The term derives from the phrase ‘endogenous morphines’. Endorphins Pain-killing substances produced in the human body and released by stress or trauma. Some researchers think that people who mutilate themselves are trying to trigger the release of endorphins. Mentioned in: Methadone , Pet Therapy , Self-Mutilation , Stress Reduction endorphins group of opioid peptides made in nerve cells in the brain and released from their axons as neurotransmitters or neurohormones, which bind to and activate opioid receptors of other cells (where opioid drugs also act). The first to be identified in brain tissue (1970s) were named enkephalins; many more were later identified. They are released in strenuous exercise and in stressful or painful situations. Subgroups have varied and widespread actions, diminishing the sensation of pain, inducing euphoria (e.g. 'runner's high') and interacting with the immune system. endorphins naturally occurring opioids liberated within brain, spinal cord and peripheral tissues during exercise; interact with tissue opiate receptors, inducing pain reduction, euphoria and general well-being endorphins, n.pl polypeptides produced in the body that bind the neuroreceptors in brain and act on the central and peripheral nervous system to alleviate pain. en·dor·phins (en-dōr'finz)

Endorphins

What hormone was discovered by John Jacob Abel?

Neurotransmitters - Anatomy & Physiology - WikiVet English Neurotransmitters - Anatomy & Physiology Created by the veterinary profession for you - find out more about WikiVet Did you know you can edit or help WikiVet® in other ways? Contents Image from Aspinall, The Complete Textbook of Veterinary Nursing , Elsevier Health Sciences, All rights reserved Neurotransmitters are chemicals that are used to relay, amplify and modulate signals between neurones and cells. They can be classified into two main groups; small-molecule transmitters (SMT) and neuropeptides. SMTs are synthesised within nerve terminals via enzymes that are produced within the cell body. Within most nerve junctions, the terminal membrane of the nerve contains numerous specific transport proteins that facilitate the transport of the majority of the SMTs back into the nerve terminal, effectively recycling the neurotransmitter. Neuropeptides are constructed of around 3 - 40 amino acid molecules that are synthesised within the cell body and are then transported to along the axon to the nerve terminal within vesicles running along microtubules. Neuropeptides are broken down by extracellular enzymes called peptidases once the neurotransmitter has been released. A small proportion of neuropeptides can bind to postsynaptic receptors in the nerve terminal membrane and can be taken up by endocytosis, although the degree of recycling of neuropeptides is lower than that of SMTs. Small-Molecule Neurotransmitters There are two major sub-groups of SMTs; amino acids and biogenic amines. All SMTs play an important role within the central nervous system with the exception of acetylcholine and norepinephrine which both are important within the peripheral nervous system. Amino Acids Amino acid glutamate is the most common excitatory SMT in the central nervous system whilst gamma-aminobutyric acid (GABA) is the most common inhibitory SMT. Other amino acid SMTs include aspartate and glycine. When glutamate is released it facilitates the opening of sodium channels within the post-synaptic membrane allowing sodium ions to enter the membrane and causing depolarisation. Therefore glutamate makes it easier for the cell to reach its depolarisation threshold and generate an action potential. Due to this, Glutamate is classified as an excitatory neurotransmitter. Glycine is present in the spinal cord and is crucial for limb movement; in particular the motor function associated with limb reflexes. When both glycine and GABA are released they result in the opening of chloride ion channels within the post synaptic membrane resulting in the membrane becoming hyperpolarised. The cytosolic side of the membrane becomes more negative. Therefore both neurotransmitters make it more difficult for the cell to reach its depolarisation threshold to generate an action potential, thus classed as inhibitory. GABA Aspartic Acid Biogenic Amines Biogenic amines are synthesised from only several types of amino acids. Which amino acids are used in their formation depends on their classification. Biogenic amines that are derived from the amino acid tyrosine are classified as catecholamines and include the SMTs norepinephrine (NE) (noradrenaline), epinephrine (E) (adrenaline), melatonin and dopamine (DA). Adrenergic neurons release norepinephrine. The biogenic amine that is derived from the amino acid tryptophane is called serotonin (5-HT) whilst the SMT derived from histidine is called histamine (HA). Serotonergic neurons release serotonin. Whilst these SMTs are primarily of importance in the central nervous system, norepinephrine is predominantly found in the peripheral nervous system. Epinephrine is produced by the adrenal glands. It is primarily involved in an overall activation of the sympathetic nervous system and is involved in the management of stress. Norepinephrine is also produced by adrenal glands and is involved in the initiation and maintainance of consciousness within the sympathetic nervous system. Both types of neurotransmitter utilise α or β receptors and are metabotropic. If an α1 adrenergic receptor is bound this will result in depolarisation of the cell and vasoconstriction of the skin and viscera. If a β1 receptor is bound this will also result in cellular depolarisation and an increase in heart rate and contractility. If a β2 receptor is bound this will result in hyperpolarisation of the cell which will cause dilation of the bronchioles of the lung. Dopamine is involved in motivation as well as love and addiction. It is effectively a 'reward system' for the brain. Dopamine also affects the way in which the basal ganglia of the brain affect our movements and a shortage of dopamine can result in diseases such as Parkinson's. Dopamine is the primary neuroendocrine regulator of prolactin from the anterior pituitary gland . It is thus often called prolactin-inhibiting hormone in reproduction. Dopamine produced by the hypothalamus is secreted via the hypothalamo-hypophysal blood vessels which supply the pituitary gland. Secretion of prolactin via lactotrope cells within the pituitary is inhibited by dopamine. Serotonin is involved in emotions, mood, sexuality, consciousness, sleep and thermoregulation. Serotonin is utilised by the central nervous system and the gastro-intestinal system. Serotonin has also been linked to mechanisms controlling pulmonary and cerebral vascular vasoconstriction. Melatonin is responsible for the regulation of onset of sleep and also for seasonal changes in the body such as winter weight gain and mating seasons. Histamine release results in increased gastric secretions, dilation of capillaries, constriction of bronchial smooth muscle and decreased blood pressure. Dopamine.png Other SMTs Other common SMTs include acetylcholine, ATP and nitric oxide. Acetylcholine (ACh) is the most common excitatory neurotransmitter in the peripheral nervous system. Cholinergic neurons release ACh and for example, are found in the neuromuscular junction . When ACh is released, it facilitates the opening of sodium channels within the post-synaptic membrane allowing sodium ions to enter the membrane and causing depolarisation. Therefore ACh makes it easier for the cell to reach its depolarisation threshold and generate an action potential. ACh has an effect on the post-synaptic membrane in skeletal muscle via nicotinic receptors, which are ionotropic (see below). ACh also exerts an effect on smooth muscle via the parasympathetic nervous system via muscarinic receptors, which are metabotropic (see below). Ach is primarily involved in skeletal muscle movement within the sympathetic nervous system and visceral movements as part of the parasympathetic nervous system. When binding to muscarinic receptors, ACh can have a number of different effects dependant on the type of receptor. If an M2 receptor is bound this will result in hyperpolarisation of the cell and a slowing of the rate of spontaneous contraction of the heart. If an M3 or an M5 receptor is bound this will result in depolarisation of the cell and contraction of smooth muscle within glands. Adenosine triphosphate (ATP), as well as having many important intracellular functions, is an important neurotransmitter and also has an autocrine and paracrine function. ATP belongs to the purines SMT group. All synaptic vesicles released by the terminal membrane of a nerve contain ATP as well as other neurotransmitters, although ATP can only function as a neurotransmitter in its own right if the post-synaptic terminal membrane contains ATP receptors. These ATP receptors are referred to as purinergic receptors. A pre-synaptic nerve terminal or terminal membrane never releases multiple types of SMT in addition to ATP, although it is common that neuropeptides are released in addition to ATP and SMTs. Other SMTs within the purine group include Guanosine triphosphate (GTP) and their derivatives. Although nitric oxide (NO) is a neurotransmitter, its characteristics differ from those discussed above. NO relies on calcium ion activation of the enzyme nitric oxide synthase (NOS) which is found throughout the nervous system and is the enzyme that is responsible for catalysing NO from the amino acid L-arginine. NO has a very short half-life and is highly reactive. It is able to pass easily through lipid membranes. What makes NO differ from the SMTs above is that is can be released in all directions rather than pre-synaptically as per the classical SMTs. Therefore NO is able to act as a signalling pathway for the post-synaptic neuron to affect the pre-synpatic neuron. Nitrous oxide is involved in enlargement of the genital organs leading to erection. Nitrous Oxide Acetylcholine Neuropeptides The neuropeptide group of neurotransmitters contain a wide range of molecules of which only the major transmitters are included below. These include; enkephalin, subtance P, LHRH, vasopressin , cholecystokinin/CKK, vasoactive intesinal peptide (VIP), endorphin, neurotensin, TRH, angiotensin-II, somatostatin and oxytocin. These neuropeptides have a wide range of effects throughout the nervous system. Many of these neuropeptides are released from nerve terminals but also as hormones from endocrine cells, cholecystokinin is an example. Vasoactive intestinal peptide (VIP) plays a role within the intestines and acts to greatly increase the secretion of water and electrolytes. VIP also causes dilation of the smooth muscle within the peripheral smooth muscles and inhibits gastrin-stimulated gastric acid secretion. The overall effect of VIP is to increase gastric motility. The neuropeptide vasopressin is responsible for metabolism and maintainance of the metabolic rate. Substance P is involved in the transmission of pain from peripheral receptors to the central nervous system. It acts to increase the sensation, and therefore the consciousness, of pain and is released when nociceptors are activated. Enkaphalin acts to inhibit the release of substance P therefore acting to diminish the sensation of pain. Endorphins and enkephalins are both examples of opioids and act within neuronal synapses to reduce the sensation of pain acting as natural pain killers. In humans, it has been shown that these neuropeptides also lead to a sense of euphoria. Both of these molecules belong to the same opioid category as morphine and heroin. They are produced by the pituitary gland and the hypothalamus and they chemically resemble opiates in their ability to produce analgesia and a sense of well-being. Endorphin has also been shown to stimulate dopaminergic neurones. In addition to this, endorphin can act to inhibit the release of substance P and therefore decrease the conscious perception of pain. Cholecystokinin or CKK is secreted as a hormone and is involved in gastric enzyme secretion . CKK affects the secretion of pancreatic enzymes but also promotes feelings of satiety within the cortex of the brain following a meal. It is also involved in smooth muscle contraction within the small intestine. Somatostatin or growth hormone-inhibiting hormone (GHIH) is a regulatory molecule within the endocrine system but also affects neurotransmission via it's interaction with G-protein coupled somatostatin receptors. It also inhibits the production of many other secondary hormones. Alpha-Endorphin Oxytocin Other Types of Neurotransmitter In many neuronal synapses, not only do the post-synaptic membranes contain receptors for neurotransmitters, they also contain ion channels. In many cases the neurotransmitter receptors and ion channels are directly linked giving rise to ionotropic receptors. When a neurotransmitter binds its relevant receptor, this also may affect the gating of adjacent ion channels, either opening or closing the channel. Ionotrophic receptors such as this are responsible for the fastest type of synaptic transmission. An example of an ionotrophic receptor is zinc which is synaptically released via this mechanism. Zinc is associated with the release of another type of neurotransmitter, neuropeptide Y. Other ion channel receptors, metabotrophic receptors, exist where the ion channel is less well associated with the neurotransmitter receptors. These receptors are affected indirectly via G-proteins or intracellular secondary messengers altering the status of the gate once an appropriate signal has been received. Despite relying on an intermediate messenger system, metabotrophic receptors can also propagate rapid signal transfers, although not as rapid as ionotrophic receptors. Function The release of excitatory neurotransmitters from the pre-synaptic membrane causes channels in the post-synaptic membrane to open and cause an increase in sodium ion concentration within the postsynaptic cell and a decrease in potassium ion concentration. This leads to a depolarisation of the postsynaptic cell, which is propagated further along the axon by an action potential (AP). Inhibitory neurotransmitters cause hyperpolarization of the postsynaptic cell making it unable to generate an action potential. Post-synaptic receptors determine the reaction of the neurotransmitter meaning that the same neurotransmitter may cause an excitatory effect on some membranes whilst exerting an inhibitory effect on others e.g ACH can be either excitatory to skeletal muscle cells or inhibitory to both smooth muscle and cardiac muscle. This article has been peer reviewed but is awaiting expert review. If you would like to help with this, please see more information about expert reviewing.

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What is the substance produced by hard exercise and oxygen debt, causing stiffness in the muscles?

Oxygen Debt & Recovery | Energy Systems | Anatomy & Physiology Oxygen Debt & Recovery Oxygen Debt & Recovery What is it all about then? When you have a short intense burst of exercise such as sprinting you generate energy for this anaerobically or without oxygen. When you stop exercising you are still breathing heavily. This is your body taking in extra oxygen to 'repay' the oxygen debt. Well, that is the simple solution but there is a little more to it if you want to look a bit deeper. True, your body has worked anaerobically and will have produced energy without some of the oxygen it would normally have used performing low intensity exercise such as slow steady running. The difference between the oxygen the body required and what it actually managed to take in during the sudden sprint is called oxygen deficit. When you stop sprinting and start to recover you will actually need more oxygen to recover than your body would have liked to use had enough been available. This is called Excess Post Exercise Oxygen Consumption. So why does it take more oxygen to recover then? You needed to replace the oxygen the body needed but couldnt get (oxygen deficit). Breathing rate and heart rate are elevated (to remove CO2) and this needs more oxygen. Body temperature and metabolic rate is increased and this needs more oxygen. Adrenaline and Noradrenaline are increased which increases oxygen consumption.   So after exercise there are other factors causing an increase in oxygen needs as well as repaying the lack of oxygen during exercise. The chart below is often seen and shows how the amount of oxygen used by the body changes over time. At the beginning the body works anaerobically leaving an oxygen deficit. Over time the oxygen consumption levels out to a steady state. After exercise the oxygen is pain back (oxygen debt). Notice the area of oxygen debt is greater than the area of oxygen deficit for the reasons stated above. What has Lactic Acid got to do with it? Lactic acid is a by product of exercising without using oxygen (anaerobially). It is essential this is removed but it is not necessarily a waste product. It is recycled into other useful chemicals: During prolonged intensive exercise (e.g. 800m race) the heart may get half its energy from lactic acid. It is converted back to pyruvic acid and used as energy by the heart and other muscles. It is thought that 70% of lactic acid produced is oxidised, 20% is converted to glucose (energy) in the liver. 10% is converted to protein. How long does it take to remove lactic acid? About 1 hour if cooling down with gentle exercise. It can take 2 hours or more if you dont warm down with gentle exercise. More Anatomy & Physiology

Lactic acid

Where would you find the carotid arteries?

Why does lactic acid build up in muscles? And why does it cause soreness? - Scientific American Scientific American Advertisement | Report Ad Stephen M. Roth, a professor in the department of kinesiology at the University of Maryland, explains. As our bodies perform strenuous exercise, we begin to breathe faster as we attempt to shuttle more oxygen to our working muscles. The body prefers to generate most of its energy using aerobic methods, meaning with oxygen. Some circumstances, however, --such as evading the historical saber tooth tiger or lifting heavy weights--require energy production faster than our bodies can adequately deliver oxygen. In those cases, the working muscles generate energy anaerobically. This energy comes from glucose through a process called glycolysis, in which glucose is broken down or metabolized into a substance called pyruvate through a series of steps. When the body has plenty of oxygen, pyruvate is shuttled to an aerobic pathway to be further broken down for more energy. But when oxygen is limited, the body temporarily converts pyruvate into a substance called lactate, which allows glucose breakdown--and thus energy production--to continue. The working muscle cells can continue this type of anaerobic energy production at high rates for one to three minutes, during which time lactate can accumulate to high levels. A side effect of high lactate levels is an increase in the acidity of the muscle cells, along with disruptions of other metabolites. The same metabolic pathways that permit the breakdown of glucose to energy perform poorly in this acidic environment. On the surface, it seems counterproductive that a working muscle would produce something that would slow its capacity for more work. In reality, this is a natural defense mechanism for the body; it prevents permanent damage during extreme exertion by slowing the key systems needed to maintain muscle contraction. Once the body slows down, oxygen becomes available and lactate reverts back to pyruvate, allowing continued aerobic metabolism and energy for the body¿s recovery from the strenuous event. Contrary to popular opinion, lactate or, as it is often called, lactic acid buildup is not responsible for the muscle soreness felt in the days following strenuous exercise. Rather, the production of lactate and other metabolites during extreme exertion results in the burning sensation often felt in active muscles, though which exact metabolites are involved remains unclear. This often painful sensation also gets us to stop overworking the body, thus forcing a recovery period in which the body clears the lactate and other metabolites. Researchers who have examined lactate levels right after exercise found little correlation with the level of muscle soreness felt a few days later. This delayed-onset muscle soreness, or DOMS as it is called by exercise physiologists, is characterized by sometimes severe muscle tenderness as well as loss of strength and range of motion, usually reaching a peak 24 to 72 hours after the extreme exercise event. Though the precise cause of DOMS is still unknown, most research points to actual muscle cell damage and an elevated release of various metabolites into the tissue surrounding the muscle cells. These responses to extreme exercise result in an inflammatory-repair response, leading to swelling and soreness that peaks a day or two after the event and resolves a few days later, depending on the severity of the damage. In fact, the type of muscle contraction appears to be a key factor in the development of DOMS. When a muscle lengthens against a load--imagine your flexed arms attempting to catch a thousand pound weight--the muscle contraction is said to be eccentric. In other words, the muscle is actively contracting, attempting to shorten its length, but it is failing. These eccentric contractions have been shown to result in more muscle cell damage than is seen with typical concentric contractions, in which a muscle successfully shortens during contraction against a load. Thus, exercises that involve many eccentric contractions, such as downhill running, will result in the most severe DOMS, even without any noticeable burning sensations in the muscles during the event. Given that delayed-onset muscle soreness in response to extreme exercise is so common, exercise physiologists are actively researching the potential role for anti-inflammatory drugs and other supplements in the prevention and treatment of such muscle soreness, but no conclusive recommendations are currently available. Although anti-inflammatory drugs do appear to reduce the muscle soreness--a good thing--they may slow the ability of the muscle to repair the damage, which may have negative consequences for muscle function in the weeks following the strenuous event.

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Which protein forms hair and nails?

Protein is important for beautiful skin, hair and nails - Nutrition Express Articles Protein is important for beautiful skin, hair and nails Learn why protein plays such a major role in your overall health by Judy Lindberg McFarland When you look in the mirror, what do you see? Do you see soft, supple, radiant, glowing, blemish-free skin? Or do you see age spots and new wrinkles? The skin is the first "aging" sign we tend to see in ourselves. We all want to find ways to keep our skin beautiful, soft, and, we hope, wrinkle free. We will each get some wrinkles, but nobody wants them prematurely! My mother, Gladys Lindberg, had the most beautiful skin for her age of any woman I have ever seen. She far surpassed the "beauty experts" and "movie stars" in her beauty and grace. At age 85 she had a clear, peachy complexion and was virtually wrinkle free! She had no patchy "age" spots or blemished skin. She never smoked and avoided the sun whenever possible. This was natural beauty. Mother started her quest for health when she was 43 years old. She said her skin was blotchy and never radiant, but her program drastically changed the quality of her skin. Important advice for skin health A woman recently came into our store looking for a "magic formula" for her deeply wrinkled skin. She was only in her mid-40s, but said her skin had changed drastically over the past months. Being quite disturbed about the situation, she came to me wanting "that miracle cream." I talked to her for a few minutes and discovered that she had been on a severe reducing diet for several months. She had followed a diet low in protein, and over the course of those months had lost her skin tone. It had started to sag and wrinkle way beyond what would be normal for her chronological age. Most women want to be slim, but if you saw her, I'm sure you would agree, "not at that price!" Here are some things I told her that are important for healthy skin regardless of whether you're trying to lose weight or not. Collagen - the skin's "cement" Elastic skin is a sign that a person has ample collagen, the strong cement-like material that binds together the cells of your body. Collagen is a structural tissue and it is replaced very slowly. It is made of fibrous protein. In fact, collagen comprises 30 percent of the total body protein. Its strong white fibers, stronger than steel wire of the same size, and yellow elastic networks, called elastin, form the connective tissue that holds our body together. Collagen strengthens the skin, blood vessels, bones, and teeth. It is the intracellular cement that holds together the cells in various organs and tissues. Collagen is one of the most valuable proteins in the human body. A person who has been sick, or who has been on an extremely low-protein diet, very often sees the muscles in his or her arms and legs begin to sag, which is a sign that they have probably lost collagen. Start with protein The building blocks of protein are amino acids. When protein is eaten, your digestive processes break it down into amino acids, which pass into the blood and are carried throughout the body. Your cells can then select the amino acids they need for the construction of new body tissue, antibodies, hormones, enzymes, and blood cells. There are 22 different amino acids, each of which has its own characteristics, and are like the letters of the alphabet. The eight essential amino acids are like the vowels. Just as you cannot make words without vowels, so you cannot build proteins without these essential amino acids. Protein is not one substance, but literally tens of thousands of different substances. The essential amino acids must be consumed in the diet because the body does not make them. The complete proteins that contain the eight essential amino acids come from meat, poultry, fish, eggs, milk -- all dairy, cheese and soy. They are basically anything that comes from the animal. Nuts and legumes (peas and beans) contain some but not all of the essential amino acids; these are known as incomplete proteins. In various combinations, all of these amino acids are capable of forming an almost limitless variety of proteins, each serving its own purpose. Proteins are necessary for tissue repair and for the construction of new tissue. Every cell needs protein to maintain its life. Protein is also the primary substance used to "replace" worn-out or dead cells: Most white blood cells are replaced every ten days. The cells in the lining of the gastrointestinal tract and blood platelets are replaced every four days. Skin cells are replaced every 24 days. More than 98 percent of the molecules in the body are completely replaced each year! Your muscles, hair, nails, skin and eyes are made of protein. So are the cells that make up the liver, kidneys, heart, lungs, nerves, brain and your sex glands. The body's most active protein users are the hormones secreted from the various glands -- thyroxin from the thyroid, insulin from the pancreas, and a variety of hormones from the pituitary -- as well as the soft tissues, hard-working major organs and muscles. They all require the richest stores of protein. How much protein a day? Many opinions differ on the amount of protein needed in the diet. Some experts suggest very low amounts; some suggest much higher amounts, especially if body building. I have found with my nutritional counseling that most people consume a very low protein diet, especially if they tell me they are tired all the time. When I have them increase their protein during the day, usually with protein shakes, it is amazing how much better they start to feel. The following protein requirement chart is to be used only as a guideline for determining your protein requirement. You may need more, or you might be able to get by with slightly less. Your requirement depends on your percent of body fat, your weight and the physical activity you do. The higher your activity level, the more you will need to increase your dietary protein intake to repair and rebuild muscle. If you are undergoing any type of severe stress (including the stresses of cancer, burns, radiation exposure, or pregnancy), you need more. If you are susceptible to infections you may need more. Remember that antibodies, white blood cells, lymph cells, and everything our body uses to fight infections is made out of protein. I feel it is very important we look to the high side of these requirements. Daily Protein Requirements for Men and Women Over 20* Ideal Weight 110 grams 130 grams *Our calculations for this age group are based on the usual recommendation of one gram of protein per kilogram (2.2 lbs) of ideal body weight, for sedentary individuals. However, adding 20 grams of protein to the above recommendation as a safety margin will ensure getting enough protein. Pregnant women should add an additional 20 grams, and nursing mothers should add 40 grams of protein to the above recommendation. If you are physically active, exercising every day, figure one gram of protein per pound of lean (your ideal) weight. Three ounces of chicken yields approximately 20 grams of protein; one half cup of water-packed tuna contains 28 grams; eight ounces of low fat, plain yogurt has 12 grams. One egg provides six grams. An eight-ounce glass of low-fat milk has eight grams. Remember, there are excellent protein powders that are alternatives to traditional protein foods. We need to remember there is a balance of protein, fats and carbohydrates that Mother and I have basically taught. It is important to eat five times a day and include some form of protein at each meal or feeding. We have found this program has helped more people look and feel their best. This may be ideal for most people, but remember, we are "biologically different." In our nutritional program I recommend a variety of complete protein foods including fish, chicken, low-fat dairy, eggs, some red meat, quality protein powders, and nutritional yeast. Also consume an ample supply of various fresh fruits and vegetables, legumes which are complex carbohydrates and include the essential fatty acids. A strict fat-free diet is not healthy for your skin. My approach is this: You are not made of lettuce leaves. Your body is made of protein which is essential for almost every cell in your body, especially your hair, skin and nails. Recognizing deficiencies related to protein deficiencies in hair, skin and nails Puffy bags under the eyes, especially in the morning, may indicate a lack of protein. Water retention. General puffiness around the eyes, as well as swollen ankles, face, and hands, can result from a protein deficiency. Nails are made of protein, not calcium as some think. A protein deficiency can be marked by split, extremely thin nails. Nails that fail to grow quickly lack protein. The structure of the hair follicle is protein. There are eight amino acids that the body does not produce and which therefore must come from complete protein foods such as eggs, dairy (milk, cheese, yogurt, etc.), soy, meat, fish, and fowl. Quality protein powders can fill this nutritional requirement for complete protein foods. It's a great reason to use protein powders. Eat small meals often with protein at each meal. L-cysteine and L-methionine are the sulfur amino acids that form "keratin," which is the protein structure of hair. Studies have shown that supplementing with L-cysteine may prevent hair from falling out, as well as increase the diameter of the hair shaft. These amino acids have been found to increase hair growth by as much as 100 percent. These two amino acids are sold in your nutrition store, but egg yolk contains the highest amount of these two amino acids. Another easy way to add sulfur to your diet is to take MSM. The value of protein It's important to understand the value of protein in our diet. Proteins are necessary for tissue repair and for the construction of new tissue. Every cell needs protein to maintain its life. Protein is also the primary substance used to "replace" worn out or dead cells. Your muscles, hair, nails, skin, and eyes are made of protein. Those with thinning hair and too many wrinkles for your age, may lack protein. The basis for neurotransmitters in your brain, and the substances that form the body's immune response against infection, is made from protein. The most active protein users of the body are all of the hormones. Next to water, protein is the most plentiful substance in your body. In fact, if all the water was squeezed out of you, half of your dry weight would be protein. One third of this protein would be in your muscles, a fifth in your bones and cartilage, a tenth in your skin, and the rest in your other tissues and body fluids. Even 95 percent of your hemoglobin is protein. Protein is the best nutrient to eat in order to maintain an even blood sugar level, because it is metabolized over a long period of time. Protein can be converted to glucose if need be. Now you have a better understanding why I keep emphasizing the value of protein. A quick and easy way to get more protein into your diet is to use a protein powder supplement. Suggestions for choosing a protein powder Not all protein powders are alike, so it's important that you read labels. There are several types of powders dominant today. These protein powders may be used alone or in combination with other powders. Look for a powder formula that contains NO refined sugar such as white sugar, sucrose, dextrose, maltose, corn sweeteners or the artificial sweetener, aspartame. These are the four sources for protein powder that I recommend. Whey protein - concentrates and isolates Whey concentrates and isolates have gone through a manufacturing process to remove most of the carbohydrates, fat and lactose from regular whey or sweet whey. The process is called "ion exchanged" or "filtered", both of which result in almost a pure protein. It also removes the majority of lactose for those who are intolerant to milk. The protein content is about 80 percent in the whey concentrates and 90 percent in the whey isolates. One method to rate the quality of one protein versus another is called Biological Value (BV). Proteins with the highest biological value promote the most lean muscle gains. Whey concentrates and isolates have higher biological values than regular whey, milk, egg or soy. Casein (milk protein) is the predominant protein in milk. For example, the protein in cheese and cottage cheese is casein. Sometimes called calcium-caseinate, or sodium- or potassium-caseinate. It contains all the essential amino acids and is a good source of protein. It is very low in lactose. This slow digesting protein keeps you full longer since it must form a gel during digestion before it is absorbed. This slower transit time may extend the exposure to the protein in the intestines and may help increase absorption. Egg protein (egg whites or egg albumen) Egg protein used to be the gold standard against which all other proteins were measured, until whey protein became available. Egg white protein provides all twenty-two of the amino acids with a proper balance of essential amino acids. It's an excellent protein source, but not very tasty compared to the milky taste of whey or casein. Some manufacturers add egg white powder to their protein powder to boost the quality of the protein. Egg white protein powder contains no cholesterol. Soy Protein Soy protein is processed from the soybean plant and most of the fat, fiber and carbohydrate has been removed. Since it is a vegetable product, it has no cholesterol. The amino acid profile is not quite as good as the other protein sources. Do not attempt to substitute soy flour for soy protein powder. The two are very different products. Soy flour must be heated for it to be assimilated by the body. Soy is a nutritionally significant dietary source of isoflavones. These naturally occurring isoflavones are genistein, daidzein and glycitein. Recent human research suggests that these isoflavones are ideal for people of all ages, especially women concerned about bone health, those looking for an alternative to hormone replacement therapy and women experiencing menopausal symptoms. However there are differing opinions on soy and relief of menopausal symptoms. These isoflavones also work in conjunction with soy protein to lower cholesterol. Research has shown that 25 grams of soy protein a day, used as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease. Some brands use GMO soy, meaning it is from genetically modified soybeans. Most brands are switching to the more expensive non-GMO (non genetically modified) soy for this reason. Check your label and use the non-GMO brands. In summary, different proteins offer varying advantages. I suggest you consume a variety of proteins and be sure to get adequate amounts for optimal health. My favorite protein powders Lindberg Protein Blend is a scientifically designed blend of five protein sources. It's made with whey, milk and egg white protein, providing a blend of fast-release proteins for building muscle, and slow-release proteins to help suppress protein breakdown.  One serving contains: 130 calories, 25 grams of protein, 3-6 grams of carbs and 1.5-2 grams of fat. Lindberg Whey is a whey protein concentrate, which provides the highest biological value protein available. The lactose has been filtered out, leaving less than one gram per serving - an amount easily tolerated by those with lactose sensitivities. Whey is an excellent source of BCAAs (branched chain amino acids), which are important to dieters and those on an exercise or fitness program. No artificial growth hormone rBGH is used, and the whey comes from cows not given rBGH (artificial growth hormone). It is instantized with non-GMO sunflower lecithin rather than soy lecithin, so it contains no soy. One serving contains: 140 calories, 25 grams of protein, 3 grams of carbs and 2.5 grams of fat.  References: 1. Braverman, E. R. and C. C. Pfeiffer. The Healing Nutrients Within. New Canaan, CT: Keats Publishing, Inc., 1987, page 91. 2. Lindberg, Gladys and Judy McFarland. Take Charge of Your Health. San Francisco: Harper and Row, 1982, page 67. 3. Information about all deficiency symptoms can be found in: Lindberg, Gladys and Judy McFarland. Take Charge of Your Health. San Francisco: Harper and Row, 1982, pages 184-241. 4. Braverman, E. R. and C. C. Pfeiffer. The Healing Nutrients Within. New Canaan, CT: Keats Publishing, Inc., 1987, page 91. Buchanan, J. H. and M. S. Otterburn. "Some structural comparisons between cysteine-deficient and normal hair keratin." IRCS Med Sci 12 (1984): 691-692.

Keratin

Which gas released by car exhausts, stops the blood hemoglobin from working correctly?

What is Keratin? (with pictures) What is Keratin? Last Modified Date: 15 December 2016 Copyright Protected: These 10 facts about space will blow your mind Keratin is an extremely strong protein that is a major component in skin, hair, nails, hooves, horns, and teeth. The amino acids which combine to form it have several unique properties and, depending on the levels of the various amino acids, it can be inflexible and hard, like hooves, or soft, as is the case with skin. Most people interact with this tissue after it is actually dead; hair, skin, and nails are all formed from dead cells that the body sheds as new cells push up from underneath. If the dead cells are kept in good condition, they will serve as an insulating layer to protect the delicate new tissue below them. It is difficult to dissolve keratin because it contains cysteine disulfide, which means that it is able to form disulfide bridges. These bridges create a helix shape that is extremely strong, as sulfur atoms bond to each other, creating a fibrous matrix that is not readily soluble. Depending on how much cysteine disulfide keratin contains, the bond can be extremely strong to make hard cells like those found in hooves, or it can be softer to make flexible tissue like hair and skin. Because of the high levels of sulfur in this protein, it emits a distinct sulfurous odor when burned that some people find distasteful. Keratin is formed by keratinocytes, living cells that make up a large part of skin, hair, nails, and other parts of the body. The cells slowly push their way upwards, eventually dying and forming a protective layer. Thousands are shed every day, and the process can be accelerated by various medical conditions, such as psoriasis . Damage to the external layer of keratin can cause skin, hair, and nails to look unhealthy or flaky. Hair and nails on humans especially tend to become dry and brittle, because the dead keratin is being pushed to great lengths. By eating foods like gelatin and keeping hair and nails moist, they can be grown out while still remaining healthy. In general, the thicker the layer of keratin, the healthier the hair or nail is, because the dead cells outside protect the living cells at the core. Keeping the external layer moisturized will also keep it healthy and prevent cracking and splitting, whether it is forming the hooves of a horse of the skin of a human. Ad anon946647 Post 129 I don't wash my hair too excessively. In fact, I don’t use shampoo when I clean my hair; I use baking soda, then just spray apple cider vinegar, then give it a rinse. I think the hair needs its own natural oils, but too much can make it limp. So I apply rice flour to my scalp, which turns transparent when it absorbs the excess oil. My hair is now thicker because it gets to keep the right amount of oil on the strand (no more stripping) while the excess is absorbed. It's growing beautifully at the age of 44, my frizziness that I struggled with for years is going away. My hair hasn't looked this good in a long time. Lately, I wash just once a week, but now I think I can wash two or three times at most. Shampoos just strip the oils. When you are young with bountiful hair, I think a lot of people can get away with using shampoos and such but I noticed changes when I hit 36. I expect to have a lion's mane like my twenties as I continue to let it grow out. Hooray! The future looks brighter! I don't have excessive shedding like I used to. There is something to this "no poo" movement! AnnaFurst Post 128 Now I'm using Unnique's deep repair treatment which is a formaldehyde free treatment. It is really easy to use and controls my frizzy hair. It lasts for about eight weeks. anon925554 Post 127 Please do not use products that release formaldehyde. I have been experiencing itching, burning and swollen lips, eyes and face for almost four weeks now. I had a hair smoothing treatment mid December and have come to realize this is not a mere allergy! I have bee suffering miserably and would not wish this on anyone! I will be seeking additional medical help this week. I have been given a steroid cream that has not helped! I pray I am able to get back to my old self! anon346099 Post 126 After reading all this about keratin, I am certainly not going to allow it anywhere near my hair. anon326836 Post 124 I just bought pure keratin, not an actual hair product with keratin on it, but pure hydrokeratin. Can someone please tell me if I can apply it directly to my hair or do I need to dissolve it on some shampoo or hair product? anon283465 Post 121 I have never used Keratin and I'm fundamentally not interested in the Keratin-based products, but out of curiosity I have to ask: wouldn't more use of Keratin make the hair more "nail-like", so why the hair break off? anon232986 Post 119 Many thanks to all the brave women who posted their experiences of Keratin. If I have to consider and compare the possible side effects to the actual benefits then I would not proceed with Keratin. Keratin sounds to me overrated by hairdressers and salons. Glad that we can share experiences online before to avoid any massive mistakes. Many thanks, ladies and best regards anon207721 Post 117 Do not do this or any straightening treatment. My hair was severely damaged. Major breakage. I'm devastated. anon200041 Post 116 I had my second keratin treatment (Pravana) in mid June and have had serious side effects ever since. My scalp went numb, then felt burned, and every day I felt as if someone was pulling my hair out of my head. I had headaches, eye pain, a sore throat and breathing difficulties. All that and my hair not only has been breaking off, but it also comes out from the roots. I have almost no hair on the top and sides of my head. I'm forced to wear a wig every day. I regret this decision every day of my life. anon194359 Post 114 I recently had the Organic Natura Keratin Treatment or Natura Keratin done, as it was recommended by my salon as being better than the other ones since it is supposed not only to be nutritive, but also organic and they are very selective when it comes to the ingredients. I was surprised when I saw other brands' ingredients that they use and compared to this nutritionist keratin that uses only raw organic material. They explained to me that all this supposedly seals into your hair and that you have to be aware of what you really want to go into your system as they explained that our hair is an organ and everything that penetrates our hair cuticles goes into our system. So I felt relaxed knowing that whoever created this Natura Keratin was concerned about hair nutrition as well. So I think we should all be aware that whatever we put in our hair could be the same as we put into our skin and even what we eat. Since everyone is becoming more conscious about what they eat, I think we should be conscious about what we put in our hair as well. So I went online and did some research and found out that the website tells that the main ingredient comes from the aloe vera, like is the base for all the products. Now this makes sense because the product did not smell and the process was very pleasant compared to other treatments I had done before. As for the results, I cannot tell a difference, but at least know that I don’t have sealed in my hair a bunch of artificial colorants and fragrances. At least it is all natural. So I will rate this product 9 of of 10. After five weeks, my hair feels still like it did the first day. Note: I am using after care Natura keratin products, too. They seem to have keratin as the main ingredient in all of the product line so I guess that helps to prolong the care of the treatment in the hair. Thanks. anon193961 Post 112 The type of keratin i used while i was pregnant was the Natura Organic Formaldehyde Free Hair Treatment line, due to the fact that it had no formaldehyde (poison). And my results were the same as the leading brands that use outrageous amounts of formaldehyde. anon191511 Post 111 For those who are looking for scientific information about keratin, i suggest Keraplast and the Keratin Answers blog. Keraplast is one of the companies that makes keratin, using sheep's wool, and their product has been proven to be highly compatible with human hair and skin, being used in hair conditioning and shampoo products, and also for medical applications for people with skin disorders. The trademarked name for Keraplast's keratin is Replicine. Research scientist Rob Kelly has published a number of papers in various journals about the results of his research with keratin applications. anon185853 Post 110 Hello, I had the Marcia Teixeira keratin treatment done in October of 2010. I have long, thick, wavy hair that tends to frizz easily in humid weather. Prior to this treatment, I had to straighten it with a flat iron and put humectant on it afterward to keep it from getting frizzy in humid or damp weather. I thought the treatment would allow me to not have to use the flat iron so frequently. The treatment itself was tedious, to say the least. I had to leave it on my hair for a full five days after having it done, and had to keep from getting it wet and also from doing anything to put a kink in it such as pinning it back or wearing a ponytail (so needless to say after the third day my hair was really looking sad. It was limp, lifeless, and looked greasy). I could hardly wait for the fifth day to arrive. My stylist washed my hair and conditioned with the "special" shampoo and conditioner that I had to purchase in order to maintain the treatment. I will admit that, at first, my hair was beautiful. It was silky, shiny, manageable and I did not have to use the flat iron hardly at all. I went back to my stylist two weeks later to have my hair colored, and that was when everything fell apart -- literally. Not only did my hair not take the color well, but it began to get brittle and break off at the crown. The color was washing out after only two washings, and I noticed that at the crown, the color appeared to take on a different hue altogether -- almost brassy in nature. I went back to my stylist in a panic, and he agreed that my hair felt like straw. He gave me a deep conditioning treatment but it didn't help. My hair continued to break off in clumps every time I washed it. Fortunately, I have a lot of hair so I was able to camouflage the breakage, but I would tell anyone considering this treatment not to do it, because it could have ruined my hair if I had less of it to work with. I can't even begin to imagine what I would have done if my hair broke off like this and it was fine in nature. I have purchased a special shampoo and conditioner designed to prevent hair breakage and thinning and encourage growth, which I've been using for the past two months. So far, my hair has not broken off any more, however I'm still struggling with trying to camouflage the breakage and I know that it will be many more months before my hair will finally be back to a point where I don't have to hide the damage. I have always had healthy hair and this product destroyed it. I will never have this done again. Post 109 Okay, now I am seeking advice. In Sep 2008 (four months before getting married) I was given a all over bleach. This burned my hair. I went from having thick, long, curly hair to losing half my hair in two months to top it off with white hair. Now I have thin, frizzy and dull hair and it is very uneven. I was advised to do the karatin treatment as it will restore my hair? I was told by my hairdresser that those healthy hair should not use it as very harsh on the hair, but great for damaged hair as it will restore? Now that I have read so many posts, I don't want cause any more damage to my hair, so please, what do you suggest? anon179275 Post 108 With a keratin treatment, the keratin is sealed in with very high heat. In fact the directions on some of the professional products tell direct the stylists to use a 450 degree flat iron. If you have fine, colored, damaged (even slightly) your hair will almost definitely break under 450 degree heat. I don't care what they say, anything over 350 degrees is way too hot whether you are using a keratin treatment or not. anon170069 Post 107 I have been getting coppola keratin for over 2 years without any problems until recently. Anytime my hair got wet it would start falling out and snapping off, so I used the coppola shampoo and conditioner. At first I thought maybe it was something in my water, but nope, it was too much keratin in the hair and it breaks off! Not all hair dressers are aware of this fact - even the highly educated ones, because Coppola is telling them that its healthy for the hair - blah blah blah. No it's not and I am living proof. My hair is breaking off like crazy every time that it gets wet. Under the advice of the stylist, I am moisturizing to try to save it but it doesn't look good. I am not looking forward to them telling me that it's too damaged and needs to be all cut off. Do not get this treatment done! It's not healthy for the hair. It may look healthy initially but is horrible for it! anon162288 Post 106 I had a Global Keratin Treatment in Oct 2009 and was diagnosed with a brain tumor six months later. Don't do it. It is not worth your life. anon160633 Post 105 i use the keratin in my hair and now its coming out every time i comb it. what do i do? I'm scared i will go bald. my hair was nappy before i used it and now it's straight but coming out. please, please help me. can i reverse the treatment? anon159438 Post 104 I had a hairdresser apply the keratin treatment to my hair. I have longer very thick hair. *Very* curly, frizzy and sometimes it looks like straw. I have spent many dollars on products trying to tap it down and usually by the end of the day, it resembles a witch's hair. Well, I am a few weeks out from having the treatment. I'm 54 years old and have been dealing with this hair forever. I am thrilled. I have breathed a sigh of relief to have finally found something that works. I have to keep from running to the bathroom towards the end of the day to check to see how wild my hair became. I went out to lunch today and the wind just whipped my hair all over the place and I was afraid to look in the mirror. Whatever... my hair was fine! kerastrait Post 103 @101: yes you can. i have done it already and it works great. much better than a relaxer. anon156164 I am Black American. can i use keratin treatments? anon152765 Post 97 my daughter is 12 and i have had her to hairdressers, head lice specialist because she has these things on her hair that look like head lice eggs. After taking her to all these people, no one had any idea what it was. finally a scientist at the JCU townsville qld, took a a sample and identified it as keratin. This is very visible on her hair, and could anyone tell me a fast, efficient way to get rid of it. anon142797 Post 96 My name is Tara! I recently saw a coupon deal on the internet for the keratin treatment and looking into getting it. I am, however, scared! My natural hair is medium in length, really fine curly, and frizzy (yes girls, i was blessed with it all lol). I love to wear my hair with clip in extensions when i go out and i love to add volume to my hair by curling it with a curler. I was wondering if i get the treatment will my hair be really, really flat as i know they straighten it heaps during the process! I am really nervous I'm going to have flat hair which is something i really don't want. Also, will i be able to use the curler on my hair after the rebonding? will the hair curl? anon140872 Post 95 I'm just wondering if anybody could tell me what salons there are in Sydney, NSW, in the areas of parramatta, carlingford, and epping that do the Keratin treatment. And how much is it. anon138754 Post 94 I have very dull and frizzy hair, so after reading all the comments, I'm thinking to do keratin treatment. Can anyone tell me from which salon i can do keratin treatment in ajman or sharjah? anon137116 Post 93 i bleached and dyed my hair blonde. what keratin line should i use? i got the treatment done called simply smooth keratin treatment, but it really didn't make my hair super super shiny. what keratin treatment makes your hair really really shiny and smooth -- without formaldehyde? anon129692 Post 92 Too many products have excessive levels of formaldehyde. Buy an effective brazilian keratin treatment that doesn't use formaldehye, lasts for up to 5 months and revitalises and improves your hair. anon128205 i have thin straight hair. what would a keratin treatment do for me? anon127395 Post 90 I have had a couple of effective keratin treatments - i.e. they looked and felt smooth and silky while the treatment lasted, but as soon as the treatment wears off my hair's condition is so much coarser and fuzzier than ever before. So either I continue or wait months and months for it to grow out. anon126925 Post 89 I had the Coppola express done about 10 days ago. My salon has been trained how to apply the product so this is not a case of someone not knowing what they're doing. I have had a lot of hair breakage, especially the first few days. There are little short pieces now around my scalp and every time I style it there are lots of little pieces on the counter. I have never had a problem with hair breakage in the past, and I have healthy hair, only highlight it about three times a year. I have always been told I have strong hair so I am not what happens with those of us that have this result. My hair seems more frizzy now, not less. I have gone back to curly and using lots of leave in conditioner to help it repair which seems to be helping. I know of people have had great results, I am not one of them and if I knew this would happen I'd never have done it. At least it was the express as I think if I had done the full treatment the breakage would be a lot worse. anon123895 Post 88 Could you tell me please if anyone (pregnant or breastfeeding) get the treatment? i know that there is no scientific proof on the pregnant women, but i would like to know. anon121020 Post 86 please do not get the keratin treatment. I have a lot of fine, very curly hair, and had the expensive keratin done about four times. Gradually my hair got worse every time. It looked great the first time, but after that with at least four months in between. it started looking dull, with a little breakage. I stopped for about a year and then decided to have the new keratin express, which has destroyed my hair. At first it looked good, but over the past month my hair is breaking off around the crown. It doesn't seem to be stopping either. Not sure what to do as i have all the good conditioners and sulfate free shampoos. I will never get this done again, but am posting to urge people that I'm not a skeptic. I tried this several times, and over the course of the past two years the buildup, I believe, is too much for my hair to handle. I want easy to manage hair but this is not the answer. Kinky hair is what I would rather have than hair that's breaking off. anon120536 Post 85 I am seeing a lot of comments about keratin so i decided to post my two cents. Keratin contains formaldehyde and now people are complained about lumps in their throat, cancer, breathing problems and also either the customer or hair dresser have died from breathing in the fumes. That is why it is not recommended to do a keratin while you are pregnant. I used a keratin that has no formaldehyde and it worked great. I can even say i had better results. I don't know if a lot of people know about it but i went to a hair show and discovered them there. It's organic and has no formaldehyde and doesn't have any chemicals in it that turn into formaldehyde. I love my hair but i don't think it's worth putting people in the salon at risk and my heath or my hairdressers; that's insane. It's a great alternative. I requested my hairdresser to purchase it for me and now i have been using it almost a full year. I wouldn't go back. I would rather keep my curly hair than ever go back to another keratin honestly. anon109923 Post 84 I just had the keratin done on my hair for the second time in two years. It worked great for me the first time and is working great the second. I have not experienced any of the problems all of you have. I think that you need to have a professional do the treatment to your hair -- someone who is certified to perform the treatment. anon109086 can having a keratin treatment help my hair to grow? panget Post 82 I had hair rebonding treatment just last week from a salon, the hairstylist advised me to go back after two days for the first hair washed, so I went back. By mistake, the other hairstylist applied hot-oil into my hair, which is not appropriate according to the one who made my hair rebonding. So they washed it and applied another cream for cream massage treatment. I did not wash my hair on the following day as advised by the hairstylist, so I bathed the next day and found out my hair was a little frizzy and brittle and dry. Can anyone please give me some advice on what’s the right thing to do to get my hair back to normal and shiny? Will applying keratin be a big help? Please help me. Thank you so much. anon107522 Post 80 Well, all I can say is that it's brilliant. My hair has stayed smooth, silky and shiny and I've had so many complimentary comments. It's the best thing I've ever done to my hair and I love it! After I had it done, it poured with rain everyday and it was also windy, but my hair stayed frizz-free. Normally I would have had a nervous breakdown trying to cope with the frizz! Not sure how long it will last, but I will definitely continue to have it done. I might need the fringe doing in between, but I will wait and see. Hope these comments are helpful. anon103575 Post 78 I had the 'express version' of keratin straightening done two weeks ago. I only had to refrain from shampooing for 24 hours and the treatment should last two months. Way cheaper than the original version. My hair is shiny, smooth, healthy. It takes half the time to blow dry and a fraction of time to flat iron. I don't know the brand of straightener my hairdresser used but it smelled like chocolate brownie batter. I have had no side effects other than gorgeous hair! The frizz is gone! I have read that it is very important to use sulfate free and sodium chloride free shampoo after keratin straightening. It seems to be working. Hope that helps! anon103438 Post 77 I've just been told that the fragments coming out of the back of my neck are keratin. I had a neck fracture when i was younger. Is there a treatment to reduce this recurrence? anon99831 Post 75 RazorKittee I am currently using kerasmooth. it has thio in it. Have you heard of it? how do you think it compares to other keratin treatments? anon94782 Post 74 In reply to the question about keratin treatment while pregnant, the websites say no, don't have it done while pregnant. I had my long, wavy, frizzy hair straightened with keratin last week. It looked beautiful, healthy and shiny. Expensive, but then it's going to last 3-4 months. Washed it today and it's frizzy again. Bummer! The hairdresser followed the correct procedure and I did everything right - didn't get it wet or sweaty or tie it back or anything. Any clues anyone? anon94476 Post 73 hi! i was wondering, i just got the treatment done today, its really flat and i usually have really thick wavy hair, will it stay this way? and when the treatment comes out will my hair be back to normal? or will it just be half straight and frizzy? anon93396 Post 72 i am a african and i relax my with dudley's relaxer. can i get keratin treatment? razorkittee Post 71 To Anon92453, post #70: More information, please. What is the natural texture of your hair, coarse or fine, and the natural curl pattern? Was there any change at all? For instance, did you want all the curl gone, and it was just half-gone, or what? There are different methods, even with the same product, for keeping curl but losing frizz, or going totally straight. Maybe your stylist needs to try another method with the same product. Further, I would want to know more about your "chemical history." Have you had another straightening service, chemical straightener, or relaxer? What is your color history? What type of color? Is there color build-up? Do you use other protein treatments, or, God forbid , Mane and Tail? Do you have hard water, or high sulfur or other minerals in your water? Do you swim regularly? What about your medications? All of these things will affect how your hair responds to any treatment or service, and should be fully disclosed in exact detail to your stylist. Also, you stylist should be able to call the manufacturer for tech help, tell them the exact info and method, and be advised on how to correct it. If by "chemically straightening" your hair after the service, I would be very very cautious about that. Even if your hair didn't go as straight as you may have wanted it, there is still keratin infused in the hair shaft, which will affect how a chemical straightener works. Straight up, if you were my client, I would redo the original service, with the original product, and not charge for the redo. I would re-read the instructions again, make sure my flat iron was hot enough (most keratin treatments require a heat setting of 450', and most flat irons do not get that hot. Chi does not, for instance, nor the Paul Mitchell flat iron) and make sure I was doing the proper application method for the results you wanted. A second application should not be damaging to your hair, or certainly not as much as a chemical straightening--whether it is an old fashioned relaxer or "perm", or another type of permanent chemical straightener. anon92453 Post 70 I had this process done three weeks ago. My hair is not breaking, but the process did not work. Not sure if it was done incorrectly, although I think the stylist did all the right things since I watched a video before I had it done and he did everything just the way the video showed. Since it did not work, he now wants to chemically straighten it. I'm wondering if that would be okay to do after having the keratin treatment. razorkittee Post 69 I am hoping that someone with sound knowledge in this area will discuss it with me, either in this forum or via email, preferably another stylist or someone with extensive chemistry and/or product background. I have been researching these products for some time, and have come to some conclusions, but have other questions. Firstly, keratin is insoluble, as the wisegeek pointed out, unless it is exposed to a reducing agent which breaks or reforms the disulfide bonds. This means, for all intents and purposes, a relaxer such as sodium hydroxide. This being so, how then is the keratin derived from its original source, processed and bottled, and then applied to a client's hair and "bonded" to its existing keratin structure? I am interested in this, because it seems that to extract the keratin in the first place, it must be somehow reduced, then reformed in the hair shaft. OK. Then we are in the familiar ground of thioglycolates, which have the ability to reform disulfide bonds, and if enough cysteine is present, could conceivably not only reform the bonds, but make new ones, but then, is the new hair structure merely patched with free-floating, unbonded keratin and the real magic in the extra disulfide bonds? It seems to me that if keratin polymers were indeed bonding with those in the hair, the bond would be permanent unless exposed to another reducing agent, which doesn't seem to be the case in smoothing systems which gradually fade out and leave the hair in its initial curl pattern. The other "clue" that most of the keratin treatments out there are just "patching" or "coating" the hair is that in many cases the hair takes on qualities of being "over-proteinated", which is why straight placental protein is only available to licensed professionals. Over-proteinated hair becomes stiff and brittle, because the individual cells are saturated with the protein, and lose elasticity, the ability to absorb any moisture (no room in the full cells) and are prone to snap and break because the hair is so inflexible. I have seen similar results from many of the current keratin smoothing systems, and am beginning to think that I am on the right track. On another note, I believe stylists should educate themselves, and then their clients. Reading labels is a must! For instance, of all the keratin treatments I have researched, only one actually contained keratin; all the others contain plant starches, usually wheat starch or soy, but I have seen potato starch also. The polymers formed by cellulose (plant starch) are different from the polymers formed by keratin, and will not bond on a permanent level with each other. I have a lot more I would like to discuss with someone, but will wait to see what kind of responses I get to this. anon88982 Post 68 Keratin Complex is the way to go. I have used it on many clients and the results very from client to client. A lot of people think this process will give you dead straight hair straight from the shower. It doesn't! It reduces frizz, gives a shine, makes your hair soft and healthy and most of all relaxes the hair. You need to dry your hair off with an ionic hairdryer as the process is heat activated. Although the formaldehyde makes you teary eyed and smoke comes from the hair from straightening it 10 times over with a 230 degree straightener, this is all normal and if done correctly by a trained professional the keratin complex could be one of the best things for your hair! anon88030 Post 67 I just tried using Brazilian Keratin Treatment at home (bought online from Brazil). I have chemically lightened blonde hair and right now it feels like straw, not anything like the results promised. It had a foul smell during use and emitted a 'smoke' when i straightened it. I am concerned i may have inhaled some of the vapour after reading these other comments about formaldehyde etc. I wish i never used it in the first place. It's overrated. Should have just stuck to using my GHD, would have caused a lot less problems. anon85595 Post 66 I do not advise the keratin treatment with formaldehyde. I have been very ill since my treatment. I have been diagnosed with bronchospasm due to chemical exposure. I am unable to speak, and when I do, it is raspy. I get muscle spasms, and I have never been so sick in my life. I can tell you from experience, the treatment is dangerous. anon83791 Post 65 No keratin is safe. "Formaldehyde free" keratins are not safe. They aren't even formaldehyde free. They contain a certain percentage of formaldehyde because that's what gets the hair straight for a long period of time. it's false advertisement. anon80508 Post 64 I got the keratin treatment done two weeks ago and my hair has not fallen out. anon78744 Post 63 Simply put- if it lasts longer than one shampoo, it has formaldehyde or some sort of formaldehyde derivative in the formula. These are formalin or aldehyde or aldehyde. All are chemicals, all are hazardous. If it is all natural and chemical free, the treatment only lasts one shampoo. Bottom line, no B.S. anon77979 Post 62 I love Keratin! I've had my hair straight now for several months from it, it's quite expensive though, which is a downside. I was able to find it relatively cheap online anon76972 Post 61 i noticed a difference in my hair after the treatment. it was nice for awhile, but after a few weeks, i did have some breakage. anon75229 Post 60 what could be the possible sources of keratin and has it been formulated into a food supplement? anon73973 Post 59 I, like someone else here, did the Keratin treatment. Big mistake! I color my hair blonde. After the first week my hair started breaking at incredible speed. I used the have to section off my hair to flat iron it. Now I simply grab the entire piece. So much hair fell off that it takes four or five turns to grab a pony tail and before only twice. I would advice not to do it. Use what God gave you and work with it! You will be much better off. I now have brittle blond funky hair. anon69978 Could any one tell me, how does hair get Beta Keratin? anon63636 Post 56 At 450 degrees aren't you going to have formaldehyde vapor, which means you don't have to eat it, you simply have to breathe it in, and if its so safe then why does the container say to wear a mask and keep the area well ventilated when using? anon60459 Post 55 My question is why are some people so dense! How many different ways dies this poor person have to explain the sane thing? Did some people even read the article at all? Here. I guess I'll break everything down for you: Is keratin harmful to pregnant or breast feeding mothers? They said there are no proven effects. That means no side effects have been found. They said consult a doctor to be safe! Does Keratin cause cancer? No Keratin itself does not cause cancer! What does is Formaldehyde! They said there are Keratin treatments on the market with no Formaldehyde in them. So stick with those and there are no risks of cancer! They also said you gave to physically eat formaldehyde to get cancer. Who's really going to eat formaldehyde? What is it of made of? the same thing our skin and nails are already made of. It is just putting more of it back into the hair and scalp to make it healthier and stronger! is it possible that keratin in hair can be used in building construction? anon57010 Post 53 I would like to use the keratin for my six year old daughter. Is it safe? Could it cause skin allergy or anything? I will be using the one with the Jujuba extract. Brand is Trust Way. The color of the product is chocolate brown. Please advise if safe. Thank you. lvichot5 Post 52 Keratin does not cause cancer. The FDA states that formaldehyde is what may be causing cancer and although most keratin treatments contain formaldehyde there are some keratin companies that offer formaldehyde free formulas. Formaldehyde is known to cause cancer when ingested. There is formaldehyde in everything (canned food, nail polish, dry wall, carpet). Unless you are eating the keratin treatment, you are safe! And if you are still skeptical, use a formaldehyde free formula. If you are getting irritated by a keratin treatment you are using, you might be over saturating the hair or using one of the treatments that smoke when you dry. I would suggest trying to use a bit less when you do the treatment or try another formula that is used on wet/damp hair(you will still get some some vapor but anything wet when applied heat will give you a bit of steam. If worst comes to worst, try using a fan to blow away the smoke. Now as for pregnant or nursing mothers, although there are no known adverse effects, it is recommended that you consult you doctor before having the treatment done. What is the source of the keratin used in hair straightening processes? anon52541 Post 49 i want to make keratin free from formaldehyde, but does the keratin cause cancer? and does it affect me if i am preparing myself to get pregnant? please advise me. anon48081 keratin doesn't cause cancer. there are a lot of companies out the selling this product. anon45434 Post 47 hi, i had keratin done two weeks ago. i am nursing. can this harm my baby? how can it harm him? anon45161 Post 46 hi, i am a hairdresser. i was thinking if using keratin really causes cancer. anyway while working i feel my eyes burning, and the smell is really bad! can you advise me? memo I need to know the side effects of using Keratin. Does it really cause cancer? anon42305 Post 44 FDA is disputing that Keratin contains no formaldehyde. If FDA is proven correct, occupational exposure to keratin can cause nasopharyngeal cancer. So it is primarily the stylist who is at risk of getting this cancer. anon41467 Post 43 hi, i eat keratin every six months and i like the result of it, but does the keratin cause cancer? and does it affect me if i am preparing myself to get pregnant? please advise me. anon40628 Dose Keratin cause allergies on scalp or eyes? anon40536 I need to know the side effects of using Keratin. Does it really cause cancer? webomg Post 39 most of the questions are answered but i found a site that gets more in depth with Questions & Answers doddzzy does amino keratin cause cancer? anon35123 I need to know the side effects of using Keratin. Does it really cause cancer? anon33667 Post 35 i once rubbed baby oil in my scalp stupidly, a week or so my scalp grew so itchy, that as i scratched my hair fell out at the age of 23, living in England gets really windy and cold, my bed is by a window where i used to get a lot of cold draft on my head, am 25 now but want to get my hair back, my dad recently turned 50 and also started losing hair just to rule out genes. Can taking keratin help grow back my hair in the faint areas with very faint weak hair, will keratin help hairs come out of my inactive pores? manno0o Post 34 hello, i have (TS)tourette syndrome and serotonin problems, so is it OK to use keratin for my hair fixing? thank you anewlife2009 Post 33 I want to take the 6 month Keratin treatment and am worried that it causes cancer or has after effects. What shall I do? anon28530 What is the best brand of Keratin to buy? -Dina zouzi Post 30 Hi, i did the kertain treatment a month ago and it's the formaldehyde free one, but i don't like the results and i want to get rid of it? do you know how to get rid of it faster than usual? usually it takes 6 months for the hair to return to normal. so do you know anything i can do? thank you. anon27556 Post 29 If keratin is also found on the labia minora, why is the labia minora then be classified as skin, and *not* as mucous membranes? What makes them considered to be skin and not mucous membranes if they have keratin? meshmesh what about the side effects of formaldehyde content of keratin hair treatment products? anon25265 Post 26 hi i just wondered if there was a difference in the amounts of keratin in afro-Caribbean and Caucasian or bi-racial hair types? I was just wondering why the appearance and textures of the hairs in difference races are so vast. anon24878 Post 25 Hi, I had long and beautiful hair, but I just turned 45 and I thought I should change my look. I decided to cut it and go black instead of light, and I used the Keratin instead of straightening my hair. Now I feel that my hair is breaking and it feels like silk that's not how I wanted my hair to to be. can you please advise if I made a mistake by using that product. anon24237 Post 24 Hi, I had the treatment done back in October. My hair was blonde, pretty and processed blonde. My hair would break each and every time I washed it or it was washed at the salon! I had to go dark, it is still splitting and I have a mullet style now! My gray roots (at 40) are coming in, I hate the dark color, I cannot go light and my hair has 2-2 1/2" of splitting....now the salon wants to add extensions! Wrong. Leave your hair alone. Blow it out yourself. Who cares. Just don't use this "stuff". MAYBE it works on natural hair, without color or heat, but I still wouldn't do it. I wear hats now and I feel so sad. I no longer have my long, blonde, sexy, healthy hair.....not by a long shot. walid Post 23 My wife wants to take the 6 month Keratin treatment and is worried that it causes cancer or have after effects. Can you advise? anon21408 Post 22 Hi, I've been asking so much about Keratin products. And the only concern I have is that I don't want my hair to be straight. All i need is to give it a wavy fluffy look. Can you please instruct me how to do that ? anon20442 Post 21 response to jackie8263 Since KP is caused by hormonal imbalance and has a strong genetic disposition, there are medicinal treatments that can ease the symptoms both prescription and OTC. i wouldn't take any oral supplements as your keratin levels are already high. i would also stay away from using keratin based shampoos as you rub them into your scalp. however conditioners which contain keratin are fine as long as you don't use leave in conditioners or massage it into your scalp. apply to ends and your fine. limiting keratin won't lower your levels, but you won't make them any higher. anon20441 response to anon11401 Keratin, mucous membrane and labia minora All membranes are made of epithelial cells incl. mucous membranes. and all epithelial cells in order to function properly as a barrier/protective layer do have keratin. however the difference b/w labia minora and mucous membranes is that the epithelial cells which line the labia minora do not have goblet cells which produce mucous. Labia minora are considered skin folds b/c they are one the exterior of the body and their sole function is to protect the uterine entrance. anon19227 Can keratin cut through human skin? anon19143 Post 18 you can't have a keratin hair treatment if you're pregnant or breast feeding, and yes and if use the keratin treatment it will make your hair straighter and more so take the frizz away.Kertin treatments are meant to smooth out frizz and make the hair more straight, and reduce your styling time by at least 40 to 50 percent. anon18251 i want to know if Keratin causes brain cancer or cancer? anon15946 Post 16 what are the disadvantages of keratin hair treatmen? Can i make the hair keratin treatment while i am pregnant? what does it consist of? how long does it last for? what happens to the hair /how it looks like after the keratin goes away? raghda Post 14 Hi, I have long frizzy wavy hair and I want to know if Keratin will make my hair straight and how long will it remain straight? Are there any side effects of using Keratin on my hair?? anon14564 Post 12 Hi.. I did Keratin hair treatment twice and it works well on my hair :) but my question; does keratin cause cancer? I will greatly appreciate your sincere feed back. Thank You. anon11523 Post 11 Can I take keratin orally and if so, will it make my hair grow longer and faster? You see I have short, dry and brittle hair and have been on a quest to making my hair long and soft and all that good stuff. Can you shed some light on this? anon11401 Post 10 is the presence of keratin a reason why the labia minora in a female are considered to be skin folds, and not mucous membranes? That b/c the labia minora have keratin, and mucous membranes don't, the main reason why the labia minora are skin and not mucous membranes? rawcliffe Post 9 My daughter has keratosis pilaris. if i cut out foods that have keratin in them will this help? If you have any advice on this problem i would appreciate it. Moderator's reply: check out our article, What is Keratosis Pilaris? , for more information on the topic. anon8984 Post 8 Can keratin fix my nails or make them grow longer if i have really short nails? anon6206 Post 7 Hi, I have long frizzy curly hair and I want to know if Keratin will make my hair straight and how long will it remain straight? Are there any side effects of using Keratin on my hair?? anon6005 Post 6 Will collagen & keratin help my nails to become stronger and grow and how long would you say it will take for this to happen? thank you anon5447 Post 5 my hair is soft but it's a little bit wavy, will Keratin be useful in my case? jackie8263 Post 2 I have keratosis Pilaris, it is due to extra keratin in my body. My question is this...If I cut back on products or food that has keratin in them will that improve my KP? Thanks ahead for any help you can offer. anon889

i don't know

What device is added to a car's exhaust system to reduce pollution?

Fuel + Air => Hydrocarbons + Nitrogen Oxides + Carbon Dioxide + Carbon Monoxide + Sulphur Dioxide+ water Hydrocarbon emissions are fragments of fuel molecules, only partially burned. See Toxicity Hydrocarbons in exhaust. Hydrocarbons react in the presence of nitrogen oxides and sunlight to form ground-level ozone, a major component of smog. Ozone irritates the eyes, nose, throat and damages the lungs. A number of exhaust hydrocarbons are also toxic, some with the potential to cause cancer. Nitrogen Oxides Under high pressure and temperature conditions in an engine, nitrogen and oxygen atoms react to form nitrogen oxides. Nitrogen dioxide, NO2, is a brownish toxic gas, an important air pollutant. The air of cities with high levels of car ownership has a distinctly brown tinge. NO2 combines with water in the air to form nitric acid - acid rain. A complex chemistry involves NO2 combining with hydrocarbons to form the photochemical smog that poisons city dwellers. Sunlight converts unburned hydrocarbons to more reactive molecules such as aldehydes and ketones which generate peroxyacyl radicals that react with NO2 forming peroxyacyl nitrates(PANs). Catalytic converters in car exhaust systems reduce air pollution in the best case by breaking down NO2 and N20 to nitrogen (N2) and oxygen(O2). Nitrous oxide (N2O) also known as "laughing gas" has medical uses, but is a pollutant in the air. N2O, for example gives rise to nitric oxide (NO) which reacts with  and depletes ozone. N2O is a combustion product but also originates from forest fires, lightning storms nitrogen-based fertilizers and manure from farm animals. According to the US EPA industrial sources make up only about 20% of all anthropogenic sources of N2O, including the burning of fossil fuel in internal combustion engines. Indoor gas burning appliances generate N2O.  It is also a major greenhouse gas and air pollutant with about 300 times more global-warming potential than carbon dioxide. Carbon Monoxide Carbon monoxide (CO) is a colorless, odorless, poisonous gas, a product of incomplete burning of hydrocarbon-based fuels. Carbon monoxide consists of a single carbon atom and a single oxygen atom linked together (CO), the product of incomplete combustion of fuel. Most CO is produced when air-to-fuel ratios are too low in the engine during vehicle starting, when cars are not tuned properly, and at higher altitudes, where thin air reduces the amount of oxygen available for combustion. Two-thirds of the carbon monoxide emissions come from transportation sources, with the largest contribution coming from cars. In urban areas, the passenger vehicle contribution to carbon monoxide pollution can exceed 90%.Read more about Carbon Monoxide Carbon Dioxide U.S. Environmental Protection Agency (EPA) originally viewed carbon dioxide as a product of "perfect" combustion, but now views CO2 as a pollution concern. Carbon dioxide is a greenhouse gas that traps the earth's heat and contributes to Climate Change Particle Pollution and Human Disease The U.S. Environmental Protection Agency (EPA) defines fine-particle air pollution, PM10, particulate matter 10 micrometers or less in diameter. Suspended particles in the air create aerosols that are important to the behavior of whole atmosphere and play a role in determining human disease. Natural sources of atmospheric particles are volcanoes, dust storms, spontaneous forest fires, tornadoes and hurricanes. Clouds are a product of aerosols that seed the formation of water droplets. Human air pollution now dominates aerosol production over cities with negative health effects. Thick aerosols are obvious as haze and contain a complex system of particles with adherent toxic gases such as sulphur dioxide. Air pollution is associated with increased hospital admissions for cardiovascular diseases with increases in acute morbidity and mortality. D'Ippoliti et al studied 6531 patients in Rome who were hospitalized for acute myocardial infarction from January 1995 to June 1997. Air pollution data were taken from 5 city monitors. Positive associations were found for total suspended particulates, NO2 and CO. The strongest and most consistent effect was found for total suspended particulates. See Air Pollution Kills Evaporative Emissions Hydrocarbon pollutants also escape into the air through fuel evaporation - evaporation causes significant hydrocarbon pollution from cars on hot days when ozone levels are highest. Evaporative emissions occur several ways: Diurnal: Gasoline evaporation increases as the temperature rises during the day, heating the fuel tank and venting gasoline vapors. Running Loses: The hot engine and exhaust system can vaporize gasoline when the car is running. Sitting Evaporation: The engine remains hot for a period of time after the car is turned off, and gasoline evaporation continues when the car is parked. Adding Fuel: Gasoline vapors are always present in fuel tanks. These vapors are forced out when the tank is filled with liquid fuel. (See Cars and Pollution US EPA Fact Sheet OMS-5) Benzene is the main toxin in the hydrocarbon fraction of exhaust. Benzene and other less known hydrocarbons are produced in petroleum refining, and are widely used as solvents and as materials in the production of various industrial products and pesticides. Benzene also is found in gasoline and in cigarette smoke. Other environmental sources of benzene include gasoline (filling) stations, underground storage tanks that leak, wastewater from industries that use benzene, chemical spills, and groundwater next to landfills containing benzene. Exposure to benzene can cause cancer, especially leukemias and lymphomas. Benzene has a suppressive effect on bone marrow and it impairs blood cell maturation and amplification. Polycyclic aromatic hydrocarbon (PAH) PAHs are a group of chemicals that are formed during the incomplete burning of coal, oil and gas, garbage, or other organic substances. PAHs can be man-made or occur naturally. A few of the PAHs are used in medicines and to make dyes, plastics, and pesticides. They are found throughout the environment in the air, water and soil. There are more than 100 different PAH compounds. Although the health effects of the individual PAHs vary, the following 15 PAHs are considered as a group with similar toxicity: acenaphthene, acenaphthylene, anthracene, benzanthracene, benzopyrene, benzofluoranthene, benzoperylene, benzofluoranthene, chrysene dibenzanthracene, fluoranthene, fluorene, indenopyrene, phenanthrene, pyrene. Long term solutions require reduced combustion of all kinds. While vehicles with new energy sources such ethanol, biofuels, propane and natural gas can contribute to reduced air pollution, their benefit is limited if vehicle use continues at current intensities. If you pay more money to buy a hybrid car, but drive it more, you have contributed little to solving air pollution problems. If you buy a gas guzzling clunker and use only one gallon of gas to go 15 miles each week, you have contributed more to the solution. The problem with all alternative fuels is that the manufacture of fuels requires energy, distribution with a manufacturing infrastructure that consume energy, often derived from burning fossil fuels. No alternative fuel is ideal. See Switch to Biofuels Hydrogen Ultimately cars might burn hydrogen in fuel cells, but despite working prototypes, a hydrogen economy is a distant fantasy. There are many problems to be solved before hydrogen can replace fossil fuels as a portable energy source. The biggest problem is that producing hydrogen requires a large amount of energy. In Canada, there are opportunities to dam rivers and produce electricity with falling water, a non polluting, renewable energy resource. A more problematic energy source would be be nuclear reactors that "burn" uranium or plutonium.Even if new non-polluting energy sources are developed, hydrogen storage and distribution requires a new, very expensive infrastructure that could replace gasoline and diesel fuels. With once rich countries such as the USA on the verge of bankruptcy and facing the extensive repairs of already aging, derelict infrastructures, adding a new, unprecedented development costs seems unlikely. Unless, of course the priorities in the US shift dramatically. The US, for example, could adopt a sane, smart strategy, reduce its military budget by 50% and invest the money and skills in rebuilding the country's infrastructure with new sustainable energy sources. Car Emissions Testing - The Volkswagen Scandal in Sept. 2015 a scandal erupted when Volkswagen, the world's largest car manufacturer, was caught cheating on emission tests of their diesel engines. In testing lab conditions, VW could show conformity with emission standards. Subsequent independent testing of VW diesel vehicles in road tests revealed high levels of nitrogen oxides emitted in real operating conditions. Errors in media reports proliferated with talk of defeat devices and software that would fool emission tests. Relevant engineering data was not available but likely the cause of the problem was the Nitrogen Oxide converter (aka NOx storage catalytic converter ) that required injections of unburned fuel to keep the converter clean and functional. The exhaust output was supposed be free of nitrogen oxides. The computer that controlled fuel injection was programmed to inject more fuel than was needed for combustion for about 2 seconds per minute. The fuel reaching the converter would burn increasing the temperature in the converter. Burning the diesel fuel in the converter would likely increase the emission of other air pollutants. The software functioned optimally for emissions testing and was turned down or off when the engine was in service. The NO converter was a poor design that would increase fuel consumption and decrease engine performance if the converter was operated for full emissions control. Jack Baruth advocated the end of diesel cars and pickup trucks. He stated: "Western democracies encouraged diesel even though they were perfectly aware of the health hazards posed by diesel particulate exhaust. Those risks are far better documented than even the most "settled" climate science, and they are very real. Eurocrats chose diesel in order to be seen to be doing something about global warming, and the manufacturers had to abide by their choice. The result? Paris has had to ban cars for hours or even days at a time because of smog. According to The Guardian, "diesel-related health problems cost (the British National Health Service) more than 10 times as much as comparable problems caused by petrol fumes. Last year the UN's World Health Organization declared that diesel exhaust caused cancer and was comparable in its effects to secondary cigarette smoking. And that was when people thought that these diesels were meeting pollution standards! Now, of course, we know that many of them were not, and that even the diesel cars that weren't designed to cheat the tests are not performing in the real world the way they do in the test labs. In other words, diesel-powered automobiles are killing people, and in not inconsiderable numbers. The jury is in and the evidence is clear." (Jack Baruth. Road & Track. Oct 2015) A review in the Science journal, Nature, questioned the relationships between auto manufacturers and regulatory bodies: "Among the questions raised by the scandal that allowed the German car maker Volkswagen to sell 11 million vehicles containing software that cheats emissions tests, many will ask why the regulators failed to notice and halt the practice. The answer is not complicated. Regulated industries exert massive, discreet pressure on regulators such as the US Environmental Protection Agency (EPA), to stop them doing their jobs properly." To put the VW scam in perspective, the company's diesel cars are uncommon in in the USA and Canada and only contributed a small amount to air pollution, compared with other sources, even with high nitrogen oxide emissions. The big problems were corporate cheating and deliberate violation of public trust. It appears that this deception will cost VW several billion euros and is an embarrassment for all of Germany. Regulatory agencies have been alerted to their limitations and will be changing testing procedures for all new engines that include monitoring emissions during real driving tests in real driving conditions. Selective Catalytic Reduction The best method of cleaning diesel exhaust is Selective Catalytic Reduction (SCR) which converts oxides of nitrogen (NOx) emissions into benign nitrogen gas and water. SCR can deliver near-zero emissions of NOx. The NOx reduction process starts with an efficient engine design that burns clean Ultra Low Sulfur Diesel (ULSD) and produces inherently lower exhaust emissions—exhaust that is already much cleaner due to leaner and more complete combustion. The vehicle’s onboard computer regulates the addition Diesel Exhaust Fluid (UREA) in precisely metered spray patterns into the exhaust stream just ahead of the SCR converter where the conversion happens. Together with the catalyst inside the converter, the mixture undergoes a chemical reaction that produces nitrogen gas and water vapor.   Discussions of Environmental Science and Human Ecology were developed by Environmed Research Inc. Sechelt, B.C. Canada. Online Topics were developed from the 2017 book, The Environment. You will find detailed information about the weather, soils, forests, oceans,  atmosphere, air pollution, climate change, water resources, air quality and preserving habitats. The Environment is available from Persona Digital as a Printed book or as an eBook Edition for Download. The Author is Stephen J. Gislason MD . Download The Environment as an eBook. Also Read Air and Breathing. This book helps you understand air quality issues, normal breathing and the causes of breathing disorders.   Persona Book Orders Click Add to Cart buttons to begin an order for mail delivery (US and Canada). All books can be downloaded as PDF files. Click the Download buttons to order eBooks for download.  Click the book titles (center column) to read topics from each book. Print Books

Catalytic converter

Which Australian mammal lays eggs?

Controlling Pollution and Improving Performance - How Catalytic Converters Work | HowStuffWorks Controlling Pollution and Improving Performance   Prev Next   The third stage of conversion is a control system that monitors the exhaust stream, and uses this information to control the fuel injection system . There is an oxygen sensor mounted upstream of the catalytic converter, meaning it is closer to the engine than the converter. This sensor tells the engine computer how much oxygen is in the exhaust. The engine computer can increase or decrease the amount of oxygen in the exhaust by adjusting the air-to-fuel ratio. This control scheme allows the engine computer to make sure that the engine is running at close to the stoichiometric point, and also to make sure that there is enough oxygen in the exhaust to allow the oxidization catalyst to burn the unburned hydrocarbons and CO. The catalytic converter does a great job at reducing the pollution, but it can still be improved substantially. One of its biggest shortcomings is that it only works at a fairly high temperature. When you start your car cold, the catalytic converter does almost nothing to reduce the pollution in your exhaust. Up Next The Catalytic Converter Quiz One simple solution to this problem is to move the catalytic converter closer to the engine. This means that hotter exhaust gases reach the converter and it heats up faster, but this may also reduce the life of the converter by exposing it to extremely high temperatures. Most carmakers position the converter under the front passenger seat, far enough from the engine to keep the temperature down to levels that will not harm it. Preheating the catalytic converter is a good way to reduce emissions. The easiest way to preheat the converter is to use electric resistance heaters. Unfortunately, the 12-volt electrical systems on most cars don't provide enough energy or power to heat the catalytic converter fast enough. Most people would not wait several minutes for the catalytic converter to heat up before starting their car. Hybrid cars that have big, high-voltage battery packs can provide enough power to heat up the catalytic converter very quickly. Catalytic converters in diesel engines do not work as well in reducing NOx. One reason is that diesel engines run cooler than standard engines, and the converters work better as they heat up. Some of the leading environmental auto experts have come up with a new system that helps to combat this. They inject a urea solution in the exhaust pipe, before it gets to the converter, to evaporate and mix with the exhaust and create a chemical reaction that will reduce NOx. Urea, also known as carbamide, is an organic compound made of carbon, nitrogen, oxygen and hydrogen. It's found in the urine of mammals and amphibians. Urea reacts with NOx to produce nitrogen and water vapor, disposing more than 90 percent of the nitrogen oxides in exhaust gases [source: Innovations Report ]. For more information on catalytic converters and related topics, check out the links on the next page. Catalytic Converter Theft ­All over the country, SUVs and trucks are becoming targets for opportunists looking to cash in on the valuable precious metals used inside catalytic converters. A standard catalytic converter contains several hundred dollars worth of platinum, palladium and rhodium. The ground clearance on trucks and SUVs makes for easy access to the converters, so all a thief needs is a reciprocating saw and about 60 seconds. This trend has police on the lookout in many parts of the country where this kind of theft has been a problem. Police caution SUV and truck drivers to park in busy, well-lit areas.

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What is the term for something that will break down naturally?

Terms to Know Biodegradable Definition A “biodegradable” product has the ability to break down, safely and relatively quickly, by biological means, into the raw materials of nature and disappear into the environment.  These products can be solids biodegrading into the soil (which we also refer to as compostable), or liquids biodegrading into water.  Biodegradable plastic is intended to break up when exposed to microorganisms (a natural ingredient such as cornstarch or vegetable oil is added to achieve this result). Sustainable disposal of any product requires that its wastes return to the earth and are able to biodegrade.  Nature biodegrades everything it makes back into basic building blocks, so that new living things can be made from the old.  Every resource made by nature returns to nature - plants and animals biodegrade, even raw crude oil will degrade when exposed to water, air and the necessary salts.  Nature has perfected this system - we just need to learn how to participate in it. By the time many resources are turned into products, however, they have been altered by industry in such a way that they are unrecognizable to the microorganisms and enzymes that return natural materials to their basic building blocks.  Crude oil, for example, will biodegrade in its natural state, but once it is turned into plastic, it becomes an unsustainable pollution problem.  Instead of returning to the cycle of life, these products simply pollute and litter our land, air and water. Of all the environmental buzzwords “biodegradable” has perhaps been the most misused and the most difficult to understand.  Because in the past there have been no guidelines or regulations, many products have called themselves biodegradable without any real justification.  Unfortunately, the word biodegradable has frequently been applied to products that generally aren’t (such as detergents or plastics) and almost never used for products that really are (such as soap or paper). A leaf is a perfect example of a biodegradable product -- it is made in the spring, used by the plant for photosynthesis in the summer, drops to the ground in autumn and assimilated into the soil to nourish the plant for the next season.  The basic concept seems straightforward enough, however, there are several factors to consider in determining the biodegradability of a product or material. The first is the question of the inherent biodegradability of the material.  Any material that comes from nature will return to nature as long as it is still in a relatively natural form.  Therefore, any plant-based, animal-based or natural mineral-based product has the capability to biodegrade, but products made from man-made petrochemical compounds generally do not.  When a manmade compound is formulated in a laboratory, combinations of elements are made that do not exist in nature and there are no corresponding microorganisms to break them down. The next issue is how long it takes for the material to actually break down.  In nature, different materials biodegrade at different rates.  A leaf takes approximately a year to become part of the forest floor.  An iron shovel, on the other hand, can take years to rust away to nothing and a large tree can take decades to completely break down.  Common sense tells us that any material will ultimately biodegrade, even if it takes centuries. So what is the proper rate for a material to be biodegradable?  It really depends on the material itself.  The leaf example suggests that the proper rate is that which is appropriate to the ecosystem. A liquid going into a waterway should biodegrade fairly quickly, whereas there’s no harm done if it takes a while for a newspaper to break down.  Plastics, on the other hand, will not biodegrade in anyone’s lifetime and certainly will never break back down into the petroleum from which it is made. And then there is the question of what exactly does the product or material break down into and are there any toxic substances formed along the way or as the end result.  In his book The Closing Circle, ecologist Barry Commoner gives the example of the benzene unit in synthetic detergents being converted as it biodegrades into phenol (carbolic acid), a substance toxic to fish.  To be truly biodegradable, a substance or material should break down into carbon dioxide (a nutrient for plants), water and naturally occurring minerals that do not cause harm to the ecosystem (salt or baking soda, for example, are already in their natural mineral state and do not need to biodegrade). The characteristics of the environment that the substance or material is in can also affect its ability to biodegrade.  Detergents, for example, might break down in a natural freshwater “aerobic” (having oxygen) environment, but not in a “anaerobic” (lacking oxygen) environment such as sewage treatment plant digestors, or natural ecosystems such as swamps, flooded soils or surface water sediments.  Many products that are inherently biodegradable in soil, such as tree trimmings, food wastes, and paper, will not biodegrade when we place them in landfills because the artificial landfill environment lacks the light, water and bacterial activity required for the decay process to begin.  The Garbage Project, an anthropological study of our waste conducted by a group at the University of Arizona , has unearthed hot dogs, corn cobs and grapes that were twenty-five years old and still recognizable, as well as newspapers dating back to 1952 that were still easily readable.  When the conditions needed for biodegradable materials to naturally biodegrade are not provided, major garbage problems are the result.    Once it is determined that a substance or material will actually biodegrade under particular conditions, then there is the problem of actually using the product in those conditions and in an amount that can be sustained by the ecosystem that is receiving it.  The sustainable rate of biodegradation is that amount which a given ecosystem can absorb as a nutrient, and if necessary, render harmless. Soap, for example, is a natural organic product that is inherently biodegradable.  The soapy greywater from a single household may biodegrade easily in a backyard, however, if that same soap went down a sewage line that fed into a waterway along with the soap used by a million or more residents that live along that waterway, there may be waves of soapsuds on the beaches, simply because more soap would be going into the waterway than it has microorganisms to biodegrade. Oil spills are devastating not because oil doesn’t biodegrade, but rather because the amount of oil is much greater than the number of microorganisms available to degrade it.  It has been estimated that it will take 50 years for the oil spilled in 1989 by the Exxon Valdez to degrade.  Lakes and streams have become polluted because the amount of sewage dumped into them has been overwhelming.  As much as we need to consider the biodegradability of the product, we need to consider the capacity of the system the biodegradable substance or material is being placed into. Those who have attempted to define biodegradable for product labels run into the same dilemma encountered when defining recyclable -- should a product be called biodegradable if it inherently has the ability to biodegrade, or should it only be called biodegradable if it also is commonly disposed of in a way in which it really will biodegrade?  For example, should a paper grocery bag be labeled biodegradable?  It will biodegrade if placed in nature, however, it won’t biodegrade in a landfill because the conditions aren’t right. Here��s how long it takes for some commonly used products to biodegrade when they are scattered about as litter: Cotton

Biodegradation

Which is the most common gas in the atmosphere?

Decompose - definition of decompose by The Free Dictionary Decompose - definition of decompose by The Free Dictionary http://www.thefreedictionary.com/decompose v. de·com·posed, de·com·pos·ing, de·com·pos·es v.tr. 1. To separate into components or basic elements. 2. To cause to rot. v.intr. 1. To become broken down into components; disintegrate. 2. To decay; rot or putrefy. See Synonyms at decay . de′com·pos′a·bil′i·ty n. de′com·pos′a·ble adj. decompose (ˌdiːkəmˈpəʊz) vb 1. (Biology) to break down (organic matter) or (of organic matter) to be broken down physically and chemically by bacterial or fungal action; rot 2. (Chemistry) chem to break down or cause to break down into simpler chemical compounds 3. (Chemistry) to break up or separate into constituent parts 4. (Mathematics) (tr) maths to express in terms of a number of independent simpler components, as a set as a canonical union of disjoint subsets, or a vector into orthogonal components ˌdecomˈposable adj v. -posed, -pos•ing. v.t. 1. to separate or resolve into constituent parts or elements; disintegrate. v.i. de`com•pos′a•ble, adj. de`com•po•si′tion (-kɒm pəˈzɪʃ ən) n. I will have been decomposing you will have been decomposing he/she/it will have been decomposing we will have been decomposing you will have been decomposing they will have been decomposing Past Perfect Continuous chemical science , chemistry - the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions digest - soften or disintegrate by means of chemical action, heat, or moisture dissociate - to undergo a reversible or temporary breakdown of a molecule into simpler molecules or atoms; "acids dissociate to give hydrogen ions" crack - reduce (petroleum) to a simpler compound by cracking separate - divide into components or constituents; "Separate the wheat from the chaff" 2. decompose - lose a stored charge, magnetic flux, or current; "the particles disintegrated during the nuclear fission process" change integrity - change in physical make-up disintegrate - cause to undergo fission or lose particles 3. biodegrade - break down naturally through the action of biological agents; "Plastic bottles do not biodegrade" hang - suspend (meat) in order to get a gamey taste; "hang the venison for a few days" decay - undergo decay or decomposition; "The body started to decay and needed to be cremated" decompose verb [ˌdiːkəmˈpəʊz] vi [body, plant] → se décomposer decompose vi → zerlegt werden ; (= rot) → sich zersetzen decompose decompose (diːkəmˈpouz) verb (of vegetable or animal matter) to (cause to) decay or rot. Corpses decompose quickly in heat. ontbind, verrot يُحَلِّل، يَتَحَلَّل разлагам се decompor rozkládat se verwesen rådne; nedbrydes αποσυνθέτω , αποσυντίθεμαι descomponerse lagundama, mädanema متلاشی شدن؛ تجزیه شدن maatua décomposer לְהַרקִיב, לְהִתפָּרֵק सड़ना, गलना, अपघटित हो जाना trunuti, raspadati se elrothad membusuk rotna decomporre , decomporsi 腐敗分解する 분해되다, 부패하다 (su)irti sairt; trūdēt urai ontbinden bryte ned , oppløse , råtne rozkładać (się) تحليل كول، تجزيه كول، جلاجلا كول، برخې برخې كول، خوسا كول، جلاجلا كېدل، خو سا كېدل decompor a (se) des­compune разлагаться rozkladať sa razkrajati (se) raspadati se lösa[s] upp, bryta[s] ner, ruttna ทำให้เน่าเปื่อย (ทางชีววิทยา) çürümek 腐爛 розкладати(ся); гнити گلنا ، تحلیل ہونا phân huỷ 腐烂 decomposition (diːkompəˈziʃən) noun ontbinding, verrotting تَحَلُّل، انْحِلال разлагане decomposição rozklad die Verwesung forrådnelse; nedbrydelse αποσύνθεση descomposición lagundamine, mädanemine تجزیه؛ تلاشی maatuminen décomposition הִתְפַּקרוּת सड़न, अपघटन, विश्लेषण raspadati se, trunuti (fel)bomlás pembusukan rotnun decomposizione 腐敗分解 부패, 분해 irimas sairšana; trūdēšana pereputan ontbinding nedbrytning , oppløsning , forråtnelse rozkład تجزيه ، تلاشى decomposição des­com­punere разложение rozklad razkrajanje raspadanje upplösning, sönderfall, förruttnelse การเน่าเปื่อย çürüme 腐爛，分解 розпад; розклад عمل تحلیل sự phân huỷ 腐烂，分解 ˌdecomˈposer noun something that causes a substance to rot or break up into simpler parts. ontbinder مادَّةٌ مُحَلِّلَه нещо, което спомага за разлагането decompositor rozkládající síla/činitel der Zersetzer noget, som nedbryder; noget, som skaber forrådnelse παράγοντας που προκαλεί αποσύνθεση agente de descomposición lagundaja تجزیه کننده hajottaja agent de décomposition מפרק विच्छिन, सड़ाने या विश्लेषण करने वाला koji uzrokuje truljenje szétbontó erő, szer pembusuk sem veldur rotnun agente di decomposizione 腐敗分解作用のあるもの 분해자 ardomoji/skaidomoji medžiaga viela, kas veicina sairšanu/trūdēšanu pengurai ontbindingsmiddel noe som bryter ned; kompostkvern środek rozkładający تجزیه کول agent de descompunere редуцент rozkladajúci činiteľ razkrojilo izazivač raspadanje nedbrytare สิ่งที่ทำให้เน่าเปื่อย ayrıştıran 分解物 редуцент محلل cái gây ra sự phân huỷ 分解体（分解已败死的原生质之有机体） de·com·pose v. descomponerse, corromperse; [food] podrirse, pudrirse.

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Which fuel is formed by the fossilization of plants?

DOE - Fossil Energy: How Fossil Fuels Were Formed You are here:  Educational Activities  >  Energy Lessons  >  Coal-Introduction  > Fossil Fuel Formation How Fossil Fuels were Formed Contrary to what many people believe, fossil fuels are not the remains of dead dinosaurs. In fact, most of the fossil fuels we find today were formed millions of years before the first dinosaurs.   Formation of Coal   Fossil fuels were formed from plants and animals that lived 300 million years ago in primordial swamps and oceans (top). Over time the plants and animals died and decomposed under tons of rock and ancient seas (middle). Eventually, many of the seas receded and left dry land with fossil fuels like coal buried underneath it (bottom). Ten feet of prehistoric plant debris was needed to make one foot of coal.   Fossil fuels, however, were once alive! They were formed from prehistoric plants and animals that lived hundreds of millions of years ago. Think about what the Earth must have looked like 300 million years or so ago. The land masses we live on today were just forming. There were swamps and bogs everywhere. The climate was warmer. Ancient trees and plants grew everywhere. Strange looking animals walked on the land, and just as weird looking fish swam in the rivers and seas. Tiny one-celled organisms called protoplankton floated in the ocean. When these ancient living things died, they decomposed and became buried under layers and layers of mud, rock, and sand. Eventually, hundreds and sometimes thousands of feet of earth covered them. In some areas, the decomposing materials were covered by ancient seas, then the seas dried up and receded. During the millions of years that passed, the dead plants and animals slowly decomposed into organic materials and formed fossil fuels. Different types of fossil fuels were formed depending on what combination of animal and plant debris was present, how long the material was buried, and what conditions of temperature and pressure existed when they were decomposing. For example, oil and natural gas were created from organisms that lived in the water and were buried under ocean or river sediments. Long after the great prehistoric seas and rivers vanished, heat, pressure and bacteria combined to compress and "cook" the organic material under layers of silt. In most areas, a thick liquid called oil formed first, but in deeper, hot regions underground, the cooking process continued until natural gas was formed. Over time, some of this oil and natural gas began working its way upward through the earth's crust until they ran into rock formations called "caprocks" that are dense enough to prevent them from seeping to the surface. It is from under these caprocks that most oil and natural gas is produced today. The same types of forces also created coal, but there are a few differences. Coal formed from the dead remains of trees, ferns and other plants that lived 300 to 400 million years ago. In some areas, such as portions of what-is-now the eastern United States, coal was formed from swamps covered by sea water. The sea water contained a large amount of sulfur, and as the seas dried up, the sulfur was left behind in the coal. Today, scientists are working on ways to take the sulfur out of coal because when coal burns, the sulfur can become an air pollutant. (To find out about these methods, see the section " Cleaning Up Coal .") Some coal deposits, however, were formed from freshwater swamps which had very little sulfur in them. These coal deposits, located largely in the western part of the United States, have much less sulfur in them.   All of these fossil fuels have played important roles in providing the energy that every man, woman, and child in the the United States uses. With better technology for finding and using fossil fuels, each can play an equally important role in the future. To read more about these fuels � both past and present � click on:   

Coal

What kind of tide appears at full Moon?

Power Plants—The Origin of Fossil Fuels - Brooklyn Botanic Garden Power Plants—The Origin of Fossil Fuels By Janet Marinelli   |   June 1, 2003 Tree-size mosses of the carboniferous era As we see daily proof, fossil fuels make the world go round. For the past century, and especially the past 50 years, they've created vast fortunes for individuals and entire nations, powered the global economy, and provoked geopolitical tensions and sometimes wars. No news there. But did you know that current events on this petroleum-addled planet are closely linked to weird and wonderful plants that lived hundreds of millions of years ago? Recent international developments propelled me to do some paleobotanical detective work. Many people think that fossil fuels—oil, coal, and natural gas—come from the bodies of dinosaurs that ruled the earth during the mid to late Mesozoic era, 213 to 65 million years ago. Not so. The origin of oil is still a matter of scientific controversy. However, it is generally believed that the world's great oil deposits were formed from diatoms. These tiny, mostly single-celled, photosynthetic organisms were, and still are, extremely important components of phytoplankton, the basis of the food chain for all marine and freshwater animals. When viewed with a microscope, they look like little jewels in a splendid variety of forms—round, triangular, fan- and barrel-shaped, twisted like rotini pasta—and in brilliant shades of emerald and peridot. Ancient diatoms eventually became not only petroleum but also diatomaceous earth, the nontoxic pest control so popular with modern-day organic gardeners. An estimated 5,600 species of diatoms are alive today, and many more species have gone extinct; scientists surmise that at least 40,000 species have been around at one time or another since life began on this planet, about 3.5 billion years ago. The diatoms that became the crude oil so coveted today lived during the Jurassic period, 213 to 144 million years ago, the age when Stegosaurus, Apastosaurus (better known as Brontosaurus), and other giant reptiles dominated the earth's terrestrial environments. The diatoms were deposited on the beds of inland seas, lagoons, lakes, and river deltas, then transformed into liquid gold by forces like high temperature and geologic pressure. The origin of natural gas, like that of oil, is not entirely clear. The leading theory is that it also came from ages-old diatoms, but under different degrees of heat and pressure. Gigantic Club Mosses A slightly different alchemy resulted in the planet's vast coal deposits, many of them in the United States. But the plants that produced them were a lot bigger, and even more bizarre and beautiful than diatoms. Coal formed from the dead remains of magnificent trees, ferns, and other primitive plants that lived in lush swamp forests during the Carboniferous period, 360 to 286 million years ago, long before a single dinosaur roamed the land. Back then, the various continents we know today were positioned very differently. For most of the period, Laurentia (ancient North America) and Baltica (ancient Europe) were pretty much a single landmass located near the equator. The climate was warm and humid year-round—in other words, perfect for the proliferation of plant life, especially pteridophytes, or plants that reproduce by spores. Not surprisingly, under such ideal conditions, size was a major factor in the evolution of Carboniferous plants. Some plants reacted to competitive pressures by becoming taller, while others adapted to life beneath these giants. Great swamp forests grew in lowland areas, dominated by gigantic arborescent plants that were very different from the flowering trees and conifers found in today's tropical, temperate, and boreal forests. The most imposing plants in these wet forests were colossal lycopods, the ancient relatives of modern club mosses such as Lycopodium, which today generally grow just a few inches tall. The tree-sized lycopods of the Carboniferous soared to 130 feet tall. These were truly primitive-looking creatures. The evidence suggests that the largest lycopods had a main trunk with a shaggy crown of dichotomous, or occasionally bifurcating, branches. Their leaves were long and grasslike, and their reproductive structures were spore-bearing cones. Their trunks contained very little secondary wood; instead, the plants were supported by a thick, barklike periderm that enclosed soft, spongy tissue. Without enough water to keep the internal cells fully expanded, the plants would have collapsed under their own weight. As the climate of Euramerica began to change toward the end of the Carboniferous, the swamplands began to dry up, and the large lycopods disappeared, in geological terms, almost overnight. Second in height only to the great lycopods was another group of pteridophytes, magnificent tree ferns. Growing to 65 feet tall, with large, compound fronds, these were even more impressive than their descendants, the cyatheas and dicksonias, tree ferns that survive today. Unlike the lycopods, ferns diversified and increased in numbers when the Carboniferous came to a close. In fact, they apparently were so abundant in at least some later Jurassic floras that they might well have been the dominant herbaceous plants on land—imagine a brontosaur straining its enormous neck to graze on the tasty frond of a 60-foot-tall fern. Today, ferns continue to flourish, numbering just over 10,000 species worldwide. Huge Horsetails and Unlikely-Looking Conifers Tremendous horsetails were another important spore-bearing component of Carboniferous plant communities. Called calamites, they resembled gigantic versions of modern-day Equisetum and often grew in dense clumps like bamboos. Unlike today's horsetails, which top out at 3 to 6 feet, the calamites reached a height of about 50 feet. Like modern horsetails, however, they consisted of a branched aerial portion growing from an underground rhizome, and both their leaves and branches grew in circles at nodes along the stems. (Some artists' renditions look a little like chubby asparagus spears cloaked with whorls of branches cloaked in turn with whorls of lance-shaped leaves.) According to paleobotanists, even the stems were remarkably similar to those of still-existing horsetails, except that they had some secondary xylem, or vascular tissue, that accounted for the plants' considerable height and girth. Calamite spores were contained, like those of the giant club mosses, in cones. Calamites made it through the climatic transitions at the end of the Carboniferous, but subsequently declined. Today, horsetails exist as a single genus, Equisetum, consisting of about 20 species distributed around the globe. Carboniferous swamps also provided habitat for two groups of early seed plants. Many Cordaites, odd-looking early conifers with long, straplike leaves, were tall (50 to 100 feet), highly branched trees that formed extensive forests. Their leaves, up to three feet long, were arranged spirally at the tips of the youngest branches. The Cordaites produced male pollen-bearing cones and female seed-bearing conelike structures on separate branches. The other large group of primitive seed-bearing plants were the "seed ferns." They had large, pinnately compound fronds so fernlike that they were long regarded as ferns. However, instead of reproducing via spores as true ferns do, they produced walnut-size seeds directly on the foliage. Some were tall, woody trees. Both the Cordaites and the seed ferns eventually disappeared, although more advanced seed-bearing plants were soon to take over the world. Herbaceous lycopods, herbaceous trailing and scrambling horsetails, small, shrubby, or scrambling seed ferns, and a variety of small and medium-size true ferns covered the floor of Carboniferous forests. Stalking these ancient swamps were early reptiles, cockroaches as big as house cats, and dragonflies with the wingspans of modern hawks. Many of the plants and animals of the Carboniferous swamps were dependent on abundant supplies of water. In order for spore-bearing plants to reproduce, the sperm cells must swim through water on plant surfaces to reach the eggs. When tropical areas became drier and huge glaciers began to cool temperate as well as polar areas during the succeeding period, the Permian, most of the plants that flourished in the great swamp forests became extinct. Conifers, cycads, and other seed-bearing plants were better adapted to the drier conditions that came to dominate the next great era of life on earth, the Mesozoic. Yet even today, at the dawn of the 21st century, we continue to grapple with the legacy of diatoms and pteridophytes of eons past. Janet Marinelli is the former director of publishing at BBG. Her book, Plant, published by Dorling Kindersley, showcases 2,000 species worldwide that are threatened in the wild but alive in cultivation. Share This Article

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What is the term given to the study of the weather?

What do you call a person who studies weather? | Reference.com What do you call a person who studies weather? A: Quick Answer A person who uses scientific methods to study, observe or forecast atmospheric patterns and weather events is known as a meteorologist. This field can be further divided into a number of differing job types, including broadcasting, teaching, researching and forensic meteorology. Full Answer The most common undergraduate degrees associated with this profession include physics, chemistry and mathematics prior to attaining an advanced degree in meteorology. Known as "the science of the atmosphere," a meteorologist is tasked with predicting the shifts in weather and climate that can affect the lives of the public. Many meteorologists work closely with other Earth scientists, including oceanographers and hydrologists, while communicating vital weather information to governments, media outlets and industry leaders.

Meteorology

What is the name given to the outermost layer of the Earth?

Climate / Weather Terms Glossary Climate and Weather Terms Glossary A Absolute humidity The mass of water vapor in a given volume of air. It represents the density of water vapor in the air. Absolute zero A temperature of -273ºC, -460ºF, or 0ºK. Theoretically, there is no molecular motion at this temperature. Absorptivity The efficiency of radiation absorption. Acclimatization The gradual adjustment of the body to new climatic or other environmental conditions, for example, the adjustment to low levels of oxygen at high altitudes. Accretion The growth of a precipitation particle by the collision of an ice crystal or snowflake with a supercooled liquid droplet that freezes upon impact. Actual evapotranspiraton The rate of water lost from vegetation and soil, ordinarily at a slower rate than the potential rate. Actual vapor pressure See vapor pressure. Adiabatic process A process that takes place without a transfer of heat between the system (such as an air parcel) and its surroundings. In an adiabatic process compression always results in warming, and expansion results in cooling. Advection The horizontal transfer of any atmospheric property by the wind. Advection fog Occurs when warm, moist air moves over a cold surface and the air cools to below its dew point. Aerovane A device that resembles a wind vane with a propeller at one end. Used to indicate wind speed and direction. Air density Mass per unit volume of air; about 1.275 km per cubic meter at 0ºC and 1000 millibars. Air mass A large expanse of air having similar temperature and humidity at any given height. Air pressure The cumulative force exerted on any surface by the molecules composing air. Albedo The percent of radiation returning from a surface compared to that which strikes it. Altimeter An instrument that indicates the altitude of an object above a fixed level. Pressure altimeters use an aneroid barometer with a scale graduated in altitude instead of pressure. Altocumulus A middle cloud, usually white or gray. Often occurs in layers or patches with wavy, rounded masses or rolls. Altocumulus castellanus An altocumulus showing vertical development, individual cloud elements have towerlike tops, often in the shape of tiny castles. Altocumulus lenticularis A lens-shaped altocumulus cloud; a mountain-wave cloud generated by the disturbance of horizontal airflow caused by a prominent mountain range. Altostratus A middle cloud composed of gray or bluish sheets or layers of uniform appearance. In the thinner regions, the sun or moon usually appears dimly visible. Ambient air The air surrounding a cloud, or the air surrounding rising or sinking air parcels. Ambient temperature Temperature of the surrounding (ambient) air. Anemometer An instrument designed to measure wind speed. Aneroid barometer An instrument designed to measure atmospheric pressure. It contains no liquid. Annual range of temperature The difference between the warmest and coldest months at any given location. Anomalies Departures of temperature, precipitation, or other weather elements from long-term averages. Arctic air A very cold and dry air mass that forms primarily in winter and the northern interior of North America. Atmospheric window A region of the electromagnetic spectrum from 8 to 12 µm where the atmosphere is transparent to radiation. Autumnal equinox The equinox at which the sun approaches the Southern Hemisphere and passes directly over the equator. Occurs around September 23. B Barograph A recording instrument that provides a continuous trace of air pressure variation with time. Barometer An instrument that measures atmospheric pressure. The two most common barometers are the mercury barometer and the aneroid barometer. Beaufort scale A scale of wind strength based on visual assessment of the effects of wind on seas and vegetation. Black body A hypothetical object that absorbs all of the radiation that strikes it. It also emits radiation at a maximum rate for its given temperature. Blizzard A severe weather condition characterized by low temperatures and strong winds (greater than 32 mi/hr) bearing a great amount of snow. When these conditions continue after the falling snow has ended, it is termed a ground blizzard. Bora A cold katabatic wind that originates in Yugoslavia and flows onto the coastal plain of the Adriatic Sea. Bowen ratio The ratio of energy available for sensible heating to energy available for latent heating. Boyle's law When the temperature is held constant, the pressure and density of an ideal gas are directly proportional. C Ceilometer An instrument that automatically records cloud height. Centrifugal force A force directed outward, away from the center of a rotating object; equal in magnitude to the centripetal force but in the opposite direction. Centripetal force An inward-directed force that confines an object to a circular path; equal in magnitude to the centrifugal force but in the opposite direction. Charles's law With constant pressure, the temperature of an ideal gas is inversely proportional to the density of the gas. Chinook A warm, dry wind on the eastern side of the Rocky Mountains. In the Alps, the wind is called a Foehn. Cirrocumulus A high cloud that appears as a white patch of cloud without shadows. It consists of very small elements in the form of grains or ripples. Cirrostratus A high cloud appearing as a whitish veil that may totally cover the sky. Often produces halo phenomena. Cirrus A high cloud composed of ice crystals in the form of thin, white, featherlike clouds in patches, filaments, or narrow bands. Climate The accumulation of daily and seasonal weather events over a long period of time. A description of aggregate weather conditions; the sum of all statistical weather information that helps describe a place or region. Cloud base The lowest portion of a cloud. Cloudburst Any sudden and heavy rain shower. Cloud cover The amount of the sky obscured by clouds when observed at a particular location. Cloud deck The top of a cloud layer, usually viewed from an aircraft. Cloud seeding The introduction of artificial substances (usually silver iodide or dry ice) into a cloud for the purpose of either modifying its development or increasing its precipitation. Coalescence The merging of cloud droplets into a single larger droplet. Cold fog See Supercooled cloud. Cold front The leading edge of a cold air mass. Condensation Process by which water changes phase from a vapor to a liquid. Condensation nuclei Small particles in the atmosphere that serve as the core of tiny condensing cloud droplets. These may be dust, salt, or other material. Conduction The transfer of heat by molecular activity from one substance to another, or through a substance. Transfer is always from warmer to colder regions. Continental air mass An air mass that forms over land; it is normally relatively dry. Continental Climate A climate lacking marine influence and characterized by more extreme temperatures than in marine climates: therefore, it has a relatively high annual temperature range for its latitude. Continental polar air Relatively dry air mass that develops over the northern interior of North America; very cold in winter and mild in summer. Continental tropical air Warm, dry air mass that forms over the subtropical deserts of the south-western United States. Contrail (condensation trail) A cloudlike streamer frequently seen forming behind aircraft flying in clear, cold, humid air. Convection Motions in a fluid that result in the transport and mixing of the fluid's properties. In meteorology, convection usually refers to atmospheric motions that are predominantly vertical, such as rising air currents due to surface heating. The rising of heated surface air and the sinking of cooler air aloft is often called free convection. (Compare with forced convection.) Convective condensation level (CCL) The level above the surface marking the base of a cumiliform cloud that is forming due to surface heating and rising thermals. Convergence An atmospheric condition that exists when the winds cause a horizontal net inflow of air into a specified region. Cooling degree-day A form of degree-day used in estimating the amount of energy necessary to reduce the effective temperature of warm air. A cooling degree-day is a day on which the average temperature is one degree above a desired base temperature. Coriolis effect A deflective force arising from the rotation of the earth on its axis; affects principally synoptic-scale and global-scale winds. Winds are deflected to the right of the initial direction in the Northern Hemisphere, and to the left in the Southern Hemisphere. Crepuscular rays Alternating light and dark bands of light that appear to fan out from the sun's position, usually at twilight. Cumulonimbus An exceptionally dense and vertically developed cloud, often with a top in the shape of an anvil. The cloud is frequently accompanied by heavy showers, lightning, thunder, and sometimes hail. It is also known as a thunderstorm cloud. Cumulus A cloud in the form of individual, detached domes or towers that are usually dense and well defined. It has a flat base with a bulging upper part that often resembles cauliflower. Cumulus clouds of fair weather are called cumulus humilis. Those that exhibit much vertical growth are called cumulus congestur or towering cumulus. Cumulus Congestus An upward building convective cloud with vertical development between that of a cumulus cloud and a cumulonimbus. Cup anemometer An instrument used to monitor wind-speed. Wind rotation of cups generates and electric current calibrated in wind speed. Cutoff high Anticyclonic circulation system that separates from the prevailing westerly airflow and therefore remains stationary. Cutoff low Cyclonic circulation system that separates from the prevailing westerly airflow and therefore remains stationary. D Daily range of temperature The difference between the maximum and minimum temperatures for any given day. Degree days Computed from each day's mean temperature (max+min/2). For each degree that a day's mean temperature is below or above a reference temperature is counted as one degree day. Density The ratio of the mass of a substance to the volume occupied by it. Deposition A process that occurs in subfreezing air when water vapor changes directly to ice without becoming a liquid first. (Also called sublimation in meteorology.) Deposition nuclei Tiny particles in the atmosphere that serve as the core of tiny ice crystals as water vapor changes to the solid form. These are also called ice nuclei. Desert One of two types of dry climate-the driest of the dry climates. Dew Water that has condensed onto objects near the ground when their temperatures have fallen below the dew point of the surface air. Dew point (dew-point temperature) The temperature to which air must be cooled (at constant pressure and constant water vapor content) for saturation to occur. When the dew point falls below freezing it is called the frost point. Diffraction The bending of light around objects, such as cloud and fog droplets, producing fringes of light and dark or colored bands. Diffuse insolation Solar radiation that is scattered or reflected by atmospheric components (clouds, for example) to the earth's surface. Direct insolation Solar radiation that is transmitted directly through the atmosphere to the earth's surface without interacting with atmospheric components. Divergence An atmospheric condition that exists when the winds cause a horizontal net outflow of air from a specific region. Downbursts A severe localized downdraft that can be experienced beneath a severe thunderstorm. (Compare Microburst) Downdraft Downward moving air, usually within a thunderstorm cell. Drainage basin A fixed geographical region from which a river and its tributaries drain water. Drizzle Small drops between 0.2 and 0.5 mm in diameter that fall slowly and reduce visibility more than light rain. Drought A period of abnormally dry weather sufficiently long enough to cause serious effects on agriculture and other activities in the affected area. Dry adiabatic rate The rate of change of temperature in a rising or descending unsaturated air parcel. The rate of adiabatic cooling or warming is 10ºC per 1000 m (5.5ºF per 1000 ft). Dry climate A climate in which yearly precipitation is not as great as the potential loss of water by evaporation. Dust devil (or whirlwind) A small but rapidly rotating wind made visible by the dust, sand, and debris it picks up from the surface. It develops best on clear, dry, hot afternoons. E Eddy A small volume of air (or any fluid) that behaves differently from the larger flow in which it exists. Effective emissivity A correction factor, dependent on the radiational characteristics of the earth -atmosphere system, that permits application of black body radiation laws to the earth-atmosphere system Emissivity The fractional amount of radiation emitted by a given object or substance in comparison to the amount emitted by a perfect emitter. Emittance The rate at which a black body radiates energy across all wave-lengths. Entrainment The mixing of environmental air into a preexisting air current or cloud so that the environmental air becomes part of the current or cloud. Environmental lapse rate The rate of decrease of temperature with elevation. It is most often measured with a radiosonde. Equilibrium vapor pressure The necessary vapor pressure around liquid water that allows the water to remain in equilibrium with its environment. Also called saturation vapor pressure. Equinox The time when the sun crosses the plane of the earth's equator occurring about March 21 and September 22. Evaporation The process by which a liquid changes into a gas. Evapotranspiration Vaporization of water through direct evaporation from wet surfaces and the release of water vapor by vegetation. Evaporation fog Fog produced when sufficient water vapor is added to the air by evaporation. The two common types are steam fog, which forms when cold air moves over warm water, and frontal fog, which forms as warm raindrops evaporate in a cool air mass. Exosphere The outermost portion of the atmosphere. Fall Freeze date The date of occurrence in the fall of the first minimum at or below a temperature threshold. Fall streaks Falling ice crystals that evaporate before reaching the ground. Foehn See Chinook. Fog A cloud with its base at the earth's surface. It reduces visibility to below 1 km. Forced convection On a small scale, a form of mechanical stirring taking place when twisting eddies of air are able to mix. Free convection Convection triggered by intense solar heating of the earth's surface. Freeze A condition occurring over a widespread area when the surface air temperature remains below freezing for a sufficient time to damage certain agricultural crops. A freeze most often occurs as cold air is advected into a region, causing freezing conditions to exist in a deep layer of surface air. Also called advection frost. Freeze free season The number of days between the last spring freeze date and the first fall freeze date. Freezing rain and freezing drizzle Rain or drizzle that falls in liquid form and then freezes upon striking a cold object or ground. Both can produce a coating of ice on objects which is called glaze. Front The transition zone between two distinct air masses. Frontal fog See Evaporation fog. Frost (also called hoarfrost) A covering of ice produced by deposition (sublimation) on exposed surfaces when the air temperature falls below the frost point (the dew point is below freezing). Frost point See Dew point. Frozen dew The transformation of liquid dew into tiny beads of ice when the air temperature drops below freezing. Funnel cloud A rotating conelike cloud that extends down-ward from the base of a thunderstorm. When it reaches the surface it is called a tornado. G Geostrophic wind A theoretical horizontal wind blowing in a straight path, parallel to the isobars or contours, at a constant speed. The geostrophic wind results when the Coriolis force exactly balances the horizontal pressure gradient force. Glaciation The conversion of all the supercooled liquid water in a cloud into ice crystals, thus reducing the growth rate of ice crystals and hail. Glaciated cloud A cloud or portion of a cloud where only ice crystals exist. Glaze A coating of ice on objects formed when supercooled rain freezes on contact. A storm that produces glaze is called an icing storm. Glory Colored rings that appear around the shadow of an object. Graupel See Snow pellets Green flash A small, green color that occasionally appears on the upper part of the sun as it rises or sets. Ground fog See Radiation fog. Growing degree-day A form of the degree-day used as a guide for crop planting and for estimating crop maturity dates. Growing season The number of days between the last spring freeze date and the first fall freeze date. H Haboob A dust or sandstorm that forms as cold downdrafts from a thunderstorm turbulently lift dust and sand into the air. Hail Solid precipitation in the form of chunks or balls of ice with diameters greater than 5 mm. The stones fall from cumulonimbus clouds. Hailstones Transparent or partially opaque particles of ice that range in size from that of a pea to that of golf balls. Hair hygrometer An instrument used to monitor relative humidity by measuring the changes in the length of human hair that accompany humidity variations. Halos Rings or arcs that encircle the sun or moon when seen through an ice crystal cloud or a sky filled with falling ice crystals. Halos are produced by refraction of light. Haze Fine dry or wet dust or salt particles dispersed through a portion of the atmosphere. Individually these are not visible but cumulatively they will diminish visibility. Heat A form of energy transferred between systems by virtue of their temperature differences. Heat capacity The ratio of the heat absorbed (or released) by a system to the corresponding temperature rise (or fall). Heat index (HI) An index that combines air temperature and relative humidity to determine an apparent temperature-how hot it actually feels. Heat of fusion Heat released when water changes phase from liquid to solid; 80 calories per gram Heat of melting Heat required to change the phase of water from solid to liquid; 80 calories per gram. Heating degree-day A form of the degree-day used as an index for fuel consumption. Needed on days when average air temperature falls below 69 ºF (18 ºC); computed by subtracting the day's average temperature from 65 ºF. Heat lightning Distant lightning that illuminates the sky but is too far away for its thunder to be heard. Heiligenschein A faint white ring surrounding the shadow of an observer's head on a dew-covered lawn. Heterosphere The atmosphere above 80 km (50 mi) where gases are stratified, with concentrations of the heavier gases decreasing more rapidly with altitude than concentrations of the lighter gases. High inversion fog A fog that lifts above the surface but does not completely dissipate because of a strong inversion (usually subsidence) that exists above the fog layer. Highland climate Complex pattern of climate conditions associated with mountains. Highland climates are characterized by large differences that occur over short distances. Hoarfrost Fernlike crystals of ice that form by deposition of water vapor on twigs, tree branches, and other vegetation. Homosphere The atmosphere up to 80 km (50 mi) in which the proportionality of principal gaseous constituents, such as oxygen and nitrogen, is constant. Humid continental climate A relatively severe climate characteristic of broad continents in the middle latitudes between approximately 40 and 50º north latitude. This climate is not found in the southern hemisphere, where the middle latitudes are dominated by the oceans. Humid Subtropical Climate A climate generally located on the eastern side of a continent and characterized by hot, sultry summers and cool winters. Hurricane A severe tropical cyclone having winds in excess of 64 knots (74 mi/hr). Hydrograph An instrument that provides a continuous trace of relative humidity with time. Hygrometer An instrument designed to measure the air's water vapor content. The sensing part of the instrument can be hair (hair hygrometer), a plate coated with carbon (electrical hygrometer), or an infrared sensor (infrared hygrometer). Hypothermia The deterioration in one's mental and physical condition brought on by a rapid lowering of human body temperature. I Ice Cap Climate A climate that has no monthly means above freezing and supports no vegetative cover except in a few scattered high mountain areas. This climate, with its perpetual ice and snow, is confined largely to the ice sheets of Greenland and Antarctica. Ice fog A type of fog composed of tiny suspended ice particles that forms at very low temperatures. Ice nuclei Particles that act as nuclei for the formation of ice crystals in the atmosphere. Ice pellets See Sleet Indian summer An unseasonably warm spell with clear skies near the middle of autumn. Usually follows a substantial period of cool weather. Infrared radiation Electromagnetic radiation with wavelengths between about 0.7 and 1000 µm. This radiation is longer than visible radiation but shorter than microwave radiation. Insolation The incoming solar radiation that reaches the earth and the atmosphere. Intertropical convergence zone (ITCZ) The boundary zone separating the northeast trade winds of the Northern Hemisphere from the southeast trade winds of the Southern Hemisphere. Inversion An increase in air temperature with height. Ion An electrically charged atom, molecule, or particle. Ionosphere An electrified region of the upper atmosphere where fairly large concentrations of ions and free electrons exist. Iridescence Brilliant spots or borders of colors, most often red and green, observed in clouds up to about 30º from the sun. Isobar A line connecting points of equal pressure Isotach A line connecting points of equal wind speed. Isotherm A line connecting points of equal wind temperature. January thaw A period of relatively mild weather around January 20 to 23 that occurs primarily in New England; an example of a singularity in the climatic record. Jet stream Relatively strong winds concentrated within a narrow band in the atmosphere. L Lake breeze A wind blowing onshore from the surface of a lake. Lake-effect snows Localized snowstorms that form on the downwind side of a lake. Such storms are common in late fall and early winter near the Great Lakes as cold, dry air picks up moisture and warmth from the unfrozen bodies of water. Land breeze A coastal breeze that blows from land to sea, usually at night. Lapse rate The rate at which an atmospheric variable (usually temperature) decreases with height. (See Environmental lapse rate.) Latent heat The heat that is either released or absorbed by a unit mass of a substance when it undergoes a change of state, such as during evaporation, condensation, or sublimation. Lenticular cloud A cloud in the shape of a lens. Lightning A visible electrical discharge produced by thunderstorms. Longwave radiation A term most often used to describe the infrared energy emitted by the earth and the atmosphere. Magnetosphere The region around the earth in which the earth's magnetic field plays a dominant part in controlling the physical processes that take place. Mammatus clouds Clouds that look like pouches hanging from the underside of a cloud. Marine climate A climate dominated by the ocean, because of the moderating effect of water, sites having this climate are considered relatively mild. Maritime air mass An air mass that originates over the ocean. These air masses are relatively humid. Maritime polar air Cool, humid air mass that forms over the cold ocean waters of the North Pacific and North Atlantic. Maritime tropical air Warm, humid air mass that forms over tropical and subtropical oceans. Mean annual temperature The average temperature at any given location for the entire year. Mesoscale The scale of meteorological phenomena that ranges in size from a few km to about 100 km. It includes local winds, thunderstorms, and tornadoes. Mesosphere The atmospheric layer between the stratosphere and the thermosphere. Located at an average elevation between 50 and 80 km above the earth's surface. Meteorology The study of the atmosphere and atmospheric phenomena as well as the atmosphere's interaction with the earth's surface, oceans, and life in general. Microburst A strong localized downdraft less than 4 km wide that occurs beneath severe thunderstorms. A strong downdraft greater than 4 km across is called a downburst. Microclimate The climate structure of the air space near the surface of the earth. Microscale The smallest scale of atmospheric motions. Millibar(mb) A unit for expressing atmospheric pressure. Sea level pressure is normally close to 1013 mb. Mirage A refraction phenomenon that makes an object appear to be displaced from its true position. When an object appears higher than it actually is, it is called a superior image. When an object appears lower than it actually is, it is an inferior mirage. Mist Very thin fog in which visibility is greater than 1.0 km (0.62 mi). Mistral A katabatic wind that flows from the Alps down the Rhone River Valley of France to the Mediterranean coast. Mixing ratio The ratio of the mass of water vapor in a given volume of air to the mass of dry air. Moist adiabatic rate The rate of change of temperature in a rising or descending saturated air parcel. The rate of cooling or warming varies but a common value of 6ºC per 1000 m (3.3ºF per 1000 ft) is used. Molecular viscosity The small-scale internal fluid friction that is due to the random motion of the molecules within a smooth-flowing fluid, such as air. Mountain and valley breeze A local wind system of a mountain valley that blows downhill (mountain breeze) at night and uphill (valley breeze) during the day. N Nacreous clouds Clouds of unknown composition that have a soft, pearly luster and that form at altitudes about 25 to 30 km above the earth's surface. They are also called mother-of-pearl clouds. Nimbostratus A dark, gray cloud characterized by more or less continuously falling precipitation. It is not accompanied by lightning, thunder, or hail. Noctilucent clouds Wavy, thin, bluish-white clouds that are best seen at twilight in polar latitudes. They form at altitudes about 80 to 90 km above the surface. Nocturnal inversion See Radiation inversion. Offshore breeze A breeze that blows from the land out over the water. Opposite of an onshore breeze. Onshore breeze A breeze that blows from the water onto the land. Opposite of an offshore breeze. Orographic uplift The lifting of air over a topographic barrier. Clouds that form in this lifting process are called orographic clouds. Orographic precipitation Rainfall or snowfall from clouds, induced by topographic uplift. Permafrost A layer of soil beneath the earth's surface that remains frozen throughout the year. Photodissociation The splitting of a molecule by a photon. Photon A discrete quantity of energy that can be thought of as a packet of electromagnetic radiation traveling at the speed of light. Pileus cloud A smooth cloud in the form of a cap. Occurs above, or is attached to, the top of a cumuliform cloud. Polar air mass A cold air mass that forms in a high-latitude source region. Polar climates Climates in which the mean temperature of the warmest month is below 10ºC; climates that are too cold to support the growth of trees. Potential energy The energy that a body possesses by virtue of its position with respect to other bodies in the field of gravity. Potential evapotranspiration (PE) The amount of moisture that, if it were available, would be removed from a given land area by evaporation and transpiration. Potential temperature The temperature that a parcel of dry air would have if it were brought dry adiabatically from its original position to a pressure of 1000 mb. Precipitable water vapor The depth of water that would result if all the vapor in the atmosphere above a location were condensed into liquid water. Precipitation Any form of water particles-liquid or solid-that falls from the atmosphere and reaches the ground. Prevailing wind The wind direction most frequently observed during a given period. Probability forecast A forecast of the probability of occurrence of one or more of a mutually exclusive set of weather conditions. Psychrometer An instrument used to measure the water vapor content of the air. It consists of two thermometers (dry bulb and wet bulb). After whirling the instrument, the dew point and relative humidity can be obtained with the aid of tables. Pyranometer An instrument that measures the amount of radiation. Q R Radar An instrument useful for remote sensing of meteorological phenomena. It operates by sending radio waves and monitoring those returned by such reflecting objects as raindrops within clouds. Radiant energy (radiation) Energy propagated in the form of electromagnetic waves. These waves do not need molecules to propagate them, and in a vacuum they travel at nearly 300,000 km per sec. Radiation fog Fog produced over land when radiational cooling reduces the air temperature to or below its dew point. It is also known as ground fog and valley fog. Radiation inversion An increase in temperature with height due to radiational cooling of the earth's surface. Also called a nocturnal inversion. Radiosonde A balloon-borne instrument that measures and transmits pressure, temperature, and humidity to a ground-based receiving station. Rain Precipitation in the form of liquid water drops that have diameters greater than that of drizzle. Rain gage A device-usually a cylindrical container-for measuring rain-fall. Rain Shadow The region on the leeside of a mountain where the precipitation is noticeable less than on the windward side. Rawinsonde An instrument carried by weather balloons to measure the temperature, humidity, pressure, and winds of the atmosphere. Reflection The process whereby a surface turns back a portion of the radiation that strikes it. Refraction The bending of light as it passes from one medium to another Refractive index The ratio of the speed of light in a vacuum to its speed in a transparent medium. Relative humidity The ratio of the amount of water vapor actually in the air compared to the amount of water vapor the air can hold at the particular temperature and pressure. The ratio of the air's actual vapor pressure to its saturation vapor pressure. Rime ice A white, granular deposit of ice formed by the freezing of water drops when they come in contact with an object. S Santa Ana The local name given a foehn wind in southern California. Saturation vapor pressure The maximum amount of water vapor necessary to keep moist air in equilibrium with a surface of pure water or ice. It represents the maximum amount of water vapor that the air can hold at any given temperature and pressure. (See Equilibrium vapor pressure.) Scattering The process by which small particles in the atmosphere deflect radiation from its path into different directions. Scintillation The apparent twinkling of a star due to its light passing through regions of differing air densities in the atmosphere. Sea breeze A coastal local wind that blows from the ocean onto the land. The leading edge of the breeze is termed a sea breeze front. Sea level pressure The atmospheric pressure at mean sea level. Semiarid See Steppe. Sensible heat transfer Movement of heat from one place to another as a consequence of conduction or convection or both. Sensible temperature The sensation of temperature that the human body feels in contrast to the actual temperature of the environment as measured with a thermometer. Shear See wind shear. Sheet lightning A fairly bright lightning flash from distant thunderstorms that illuminates a portion of the cloud. Shortwave radiation A term most often used to describe the radiant energy emitted from the sun, in the visible and near ultraviolet wavelengths. Shower Intermittent precipitation from a cumuliform cloud, usually of short duration but often heavy. Sleet A type of precipitation consisting of transparent pellets of ice 5 mm or less in diameter. Same as ice pellets. Smog Originally smog meant a mixture of smoke and fog. Today, smog means air that has restricted visibility due to pollution, or pollution formed in the presence of sunlight-photochemical smog. Snow Solid precipitation in the form of minute ice flakes that occur below 0ºC. Snowflake An aggregate of ice crystals that falls from a cloud Snow flurries Light showers of snow that fall intermittently. Snow grains Precipitation in the form of very small, opaque grains of ice. The solid equivalent of drizzle. Snow pellets White, opaque, approximately round ice particles between 2 and 5 mm in diameter that form in a cloud either from the sticking together of ice crystals or from the process of accretion. Snow rollers A cylindrical spiral of snow shaped somewhat like a child's muff and produced by the wind. Snow squall (shower) An intermittent heavy shower of snow that greatly reduces visibility. Solstice Either of the two times of the year when the sun is the greatest distance from the celestial equator, occurring about June 22 and December 22. See winter solstice and summer solstice. Southern oscillation The reversal of surface air pressure at opposite ends of the tropical Pacific Ocean that occur during El Nino events. Specific heat The ratio of the heat absorbed (or released) by the unit mass of the system to the corresponding temperature rise (or fall). Specific humidity The ratio of the mass of water vapor in a given parcel to the total mass of air in the parcel. Spontaneous nucleation (freezing) The freezing of pure water without the benefit of any nuclei. Spring freeze date The date of occurrence in the spring of the last minimum at or below a temperature threshold. Squall line Any nonfrontal line or band of active thunderstorms. Station pressure The actual air pressure computed at the observing station. Steam fog See Evaporation fog. Steppe One of the two types of dry climate. A marginal and more humid variant of the desert that separates it from bordering humid climates. Steppe also refers to the short-grass vegetation associated with this semiarid climate. Storm surge An abnormal rise of the sea along a shore. Primarily due to the winds of a storm, especially a hurricane. Stratocumulus A low cloud, predominantly stratiform with low, lumpy, rounded masses, often with blue sky between them. Stratopause The boundary between the stratosphere and the mesosphere. Stratosphere The layer of the atmosphere above the troposphere and below the mesosphere (between 10 km and 50 km), generally characterized by an increase in temperature with height. Stratus A low, gray cloud layer with a rather uniform base whose precipitation is most commonly drizzle. Subarctic climate A climate found north of the humid continental climate and south of the polar climate and characterized by bitterly cold winters and short cool summers. Places within this climatic realm experience the highest annual temperature ranges on earth. Sublimation The process whereby ice changes directly into water vapor without melting. In meteorology, sublimation can also mean the transformation of water vapor into ice. (See Deposition.) Subsidence The slow sinking of air, usually associated wit high-pressure areas. Subsidence inversion A temperature inversion produced by the adiabatic warming of a layer of sinking air. Summer solstice Approximately June 22 in the Northern Hemisphere when the sun is highest in the sky and directly overhead at latitude 23.5º N, the Tropic of Cancer. Sundog A colored luminous spot produced by refraction of light through ice crystals that appears on either side of the sun. Also called parhelion. Sun pillar A vertical streak of light extending above (or below) the sun. It is produced by the reflection of sunlight of ice crystals. Supersaturated air A condition that occurs in the atmosphere when the relative humidity is greater that 100 percent. Surface inversion See Radiation inversion Synoptic scale The typical weather map scale that shows features such as high- and low-pressure areas and fronts over a distance spanning a continent. Also called the cyclonic scale. T Taiga The northern coniferous forest; also a name applied to the subarctic climate. Temperature The degree of hotness or coldness of a substance as measured by a thermometer. It is also a measure of the average speed or kinetic energy of the atoms and molecules in a substance. Temperature inversion An extremely stable air layer in which temperature increases with altitude, the inverse of the usual temperature profile in the troposphere. Terminal velocity The constant speed obtained by a falling object when the upward drag on the object balances the downward force of gravity. Thermal A small, rising parcel of warm air produced when the earth's surface is heated unevenly. Thermograph A recording instrument that gives a continuous trace of temperature with time. Thermometer An instrument used to measure temperature. Thermosphere The atmospheric layer above the mesosphere. It extends from 90 km to outer space. Thunder The sound due to rapidly expanding gases along the channel of a lightning discharge. Tipping bucket rain gage A device that accumulates rainfall in increments of 0.01 in. by containers that alternately fill and empty (tip). Tornado An intense, rotating column of air that protrudes from a cumulonimbus cloud in the shape of a funnel or a rope and touches the ground. (See Funnel cloud.) Trade winds The winds that occupy most of the tropics and blow from the subtropical highs to the equatorial low. Transpiration The release of water vapor to the atmosphere by plants. Tropical air mass A warm-to-hot air mass that forms in the subtropics. Tropical depression A mass of thunderstorms and clouds generally with a cyclonic wind circulation of between 20 and 34 knots Tropical disturbance An organized mass of thunderstorms with a slight cyclonic wind circulation of less than 20 knots. Tropical storm Organized thunderstorms with a cyclonic wind circulation between 35 and 64 knots. Tropopause The boundary between the troposphere and the stratosphere. Troposphere The layer of the atmosphere extending from the earth's surface up to the tropopause (about 10 km above the ground). Tundra Climate Found almost exclusively in the northern hemisphere or at high altitudes in many mountainous regions. A treeless climatic realm of sedges, grasses, mosses, and lichens that is dominated by a long, bitterly cold winter. Turbulence Any irregular or disturbed flow in the atmosphere that produces gusts and eddies. Twilight The time immediately before sunrise and after sunset when the sky remain illuminated. Typhoon A hurricane that forms in the western Pacific Ocean. Ultraviolet radiation Electromagnetic radiation with wave-lengths longer than X-rays but shorter than visible light. Upslope fog Fog formed as moist, stable air flows upward over a topographic barrier. Upslope precipitation Precipitation that forms due to moist, stable air gradually rising along an elevated plain. Upslope precipitation is common over the western Great Plains, especially east of the Rock Mountains. Upwelling The rising of water (usually cold) toward the surface from the deeper regions of a body of water. Urban heat island The increased air temperatures in urban areas as contrasted to the cooler surrounding rural areas. Valley breeze See Mountain breeze. Valley fog See Radiation fog. Vapor pressure The pressure exerted by the water vapor molecules in a given volume of air. Vernal equinox The equinox at which the sun approaches the Northern Hemisphere and passes directly over the equator. Occurs around March 20. Virga Precipitation that falls from a cloud but evaporates before reaching the ground. (See Fall streaks.) Virtual temperature An adjustment applied to the real air temperature to account for a reduction in air density due to the presence of water vapor. Viscosity The resistance of fluid flow. Visibility The greatest distance an observer can see and identify prominent objects. Visible light That portion of the electromagnetic spectrum from 0.4 to 0.7 µm wavelengths that is visible. Vorticity A measure of the spin of a fluid, usually small air parcels. Absolute vorticity is the combined vorticity due to the earth's rotation and the vorticity due to the air's circulation relative to the earth. Relative vorticity is due to the curving of the air flow and wind shear. W Wall Cloud A localized, persistent, often abrupt lowering from a rain-free base. Wall clouds can range from a fraction of a mile up to nearly five miles in diameter, and normally are found on the south or southwest (inflow) side of the thunderstorm. "Wall cloud" also is used occasionally in tropical meteorology to describe the inner cloud wall surrounding the eye of a tropical cyclone, but the proper term for this feature is eyewall. Warm front The leading edge of a warm air mass. Water balance The comparison of actual and potential evapotranspiration with the amount of precipitation, usually on a monthly basis. Water budget Balance sheet for the inputs and outputs of water to and from the various global water reservoirs. Water equivalent The depth of water that would result from the melting of a snow sample. Typically about 10 inches of snow will melt to 1 inch of water, producing a water equivalent of 10 to 1. Weather The state of the atmosphere in terms of such variables as temperature, cloudiness, precipitation, and radiation. Weighing bucket rain gage A device that is calibrated so that the weight of rainfall is recorded directly in terms of rainfall in millimeters or in inches. Wet-bulb depression The difference in degrees between the air temperature (dry-bulb temperature) and the wet-bulb temperature. Wet-bulb temperature The lowest temperature that can be obtained by evaporating water into the air. White frost Ice crystals that form on surfaces instead of dew when the dew point is below freezing. Wind chill equivalent temperature A theoretical air temperature at which the heat loss from exposed skin under calm conditions is equivalent to the heat loss at the actual air temperature and under the actual wind speeds. Wind-chill factor The cooling effect of any combination of temperature and wind, expressed as the loss of body heat. Also called wind-chill index. Wind shear A difference in wind speed or direction between two wind currents in the atmosphere. Wind Vane An instrument used to determine wind direction. Windsock A large, conical, open bag designed to indicate wind direction and relative speed; usually used at small airports. Winter solstice Approximately December 22 in the Northern Hemisphere when the sun is lowest in the sky and directly overhead at latitude 23.5ºS, the Tropic of Capricorn.

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Which country produces the world's largest quantity of municipal waste per person per year?

Global Municipal Solid Waste Continues to Grow | Worldwatch Institute Global Municipal Solid Waste Continues to Grow OECD nations generate over two kilograms of municipal solid waste per person every day.  (Photo credit: WRS Italia) Growing prosperity and urbanization could double the volume of municipal solid waste annually by 2025, challenging environmental and public health management in the world’s cities, according to new research conducted for our Vital Signs Online service. Although some of this waste is eventually recycled, the doubling of waste that current projections indicate would bring the volume of municipal solid waste—or MSW—from today’s 1.3 billion tons per year to 2.6 billion tons. As defined in the report, MSW consists of organic material, paper, plastic, glass, metals, and other refuse collected by municipal authorities, largely from homes, offices, institutions, and commercial establishments. MSW is a subset of the larger universe of waste and typically does not include waste collected outside of formal municipal programs. Nor does it include the sewage, industrial waste, or construction and demolition waste generated by cities. And of course MSW does not include rural wastes. MSW is measured before disposal, and data on it often include collected material that is later diverted for recycling. MSW tends to be generated in much higher quantities in wealthier regions of the world. Members of the Organisation for Economic Co-operation and Development  (OECD), a group of 34 industrialized nations, lead the world in MSW generation, at nearly 1.6 million tons per day. By contrast, sub-Saharan Africa produces less than one eighth as much, some 200,000 tons per day. The list of top 10 MSW-generating countries includes four developing nations (Brazil, China, India, and Mexico) in part because of the size of their urban populations and in part because their city dwellers are prospering and adopting high-consumption lifestyles. Although the United States leads the world in MSW output at some 621,000 tons per day, China is a relatively close second, at some 521,000 tons. Even among the top 10, however, there is a wide range of output: the United States generates nearly seven times more urban refuse than France, in tenth position, does. Urbanization and income levels also tend to determine the type of waste generated. The share of inorganic materials in the waste stream, including plastics, paper, and aluminum, tends to increase as people grow wealthier and move to cities. Waste flows in rural areas, in contrast, are characterized by a high share of organic matter, ranging from 40 to 85 percent.Similarly, organic waste accounts for more than 60 percent of MSW in low-income countries, but only a quarter of the waste stream in high-income countries. Roughly a quarter of the world’s garbage is diverted to recycling, composting, or digestion—waste management options that are environmentally superior to landfills and incinerators. Recycling rates vary widely by country. In the United States, the recycled share of MSW grew from less than 10 percent in 1980 to 34 percentin 2010, and similar increases have been seen in other countries, especially industrial ones. The growing interest in MSW recovery is driven by a maturation of regulations and of markets for post-consumer materials. The global market for scrap metal and paper is at least $30 billion per year, according to the World Bank . The UN Environment Programme  (UNEP) estimates the market for waste management, from collection through recycling, to be some $400 billion worldwide. Yet UNEP also estimates that to “green” the waste sector would require, among other things, a 3.5-fold increase in MSW recycling at the global level, including nearly complete recovery of all organic material through composting or conversion to energy. The gold standard for MSW will be to integrate it into a materials management approach known as a “circular economy,” which involves a series of policies to reduce the use of some materials and to reclaim or recycle most of the rest. Japan has made the circular economy a national priority since the early 1990s through passage of a steady progression of waste reduction laws, and the country has achieved notable successes. Resource productivity (tons of material used per yen of gross domestic product) is on track to more than double by 2015 over 1990 levels, the recycling rate is projected to roughly double over the same period, and total material sent to landfills will likely decrease to about a fifth of the 1990 level by 2015. Further highlights from the report: OECD nations generate the greatest quantities of garbage, more than 2 kilograms per person per day. In South Asia, the rate is less than a quarter as much, under half a kilo per person. The U.S. Environmental Protection Agency  estimates that recycling 8 million tons of metals in the United States has eliminated more than 26 million tons of greenhouse gases—the equivalent of removing more than 5 million cars from the road for a year. Each ton of recycled paper saves 17 trees and the energy equivalent of 165 gallons of gasoline compared with paper made from trees, in addition to requiring only half the water.

United States

Which sea is so highly polluted that the Barcelona Convention was set up in 976 to try and clean it up?

Daily chart: A rubbish map | The Economist A rubbish map Tweet A global comparison of garbage NOTHING evokes environmental degradation and poverty quite so vividly as pictures of slum-dwelling children scavenging through mounds of steaming waste for items to sell. Such sights are often a direct consequence of economic success and rapid urbanisation, and so could become increasingly common as the rate of urbanisation in many poor countries increases. Nearly all rubbish is generated by city-dwellers, and in a new report on municipal solid waste (MSW), the World Bank warns of the potential costs of dealing with an ever-growing deluge of garbage. The world's cities currently generate around 1.3 billion tonnes of MSW a year, or 1.2kg per city-dweller per day, nearly half of which comes from OECD countries. That is predicted to rise to 2.2 billion tonnes by 2025, or 1.4kg per person. The Bank estimates China's urbanites will throw away 1.4 billion tonnes in 2025, up from 520m tonnes today. By contrast, America's urban rubbish pile will increase from 620m tonnes to 700m tonnes.

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What is the scientific scale for measuring the hardness of rocks?

Bestcrystals.com . Mohs Hardness Scale Mohs Hardness Scale Mohs Hardness Scale The hardness of a stone is one of the properties that contribute to identification.  Hardness is also an attribute which is important to be aware of, because it may determine what a stone may be used for (jewelry, carving, faceting, handling, storage, etc.)  You may want to familiarize yourself with the Mohs Scale of Hardness.  This will help you understand the relationships between stones according to their hardness.  The Mohs Scale of Hardness consists of 10 classifications, 1 being the softest, and 10 being the hardest.  The only mineral that is an exception to this is mercury, which is liquid.  To give you a few reference points, the diamond is of course the hardest, rated 10.  Your fingernail is a 2, a pocket knife is about a 5-6, and a piece of glass is a 6-7.  Each classification will scratch the one preceding it.  As you know, a diamond (10) will scratch glass (6-7).  This technique is commonly used in the field for initial identification, and it is good to have samples of some of these stones with you in order to perform the test.  Some minerals have varying hardness according to the direction you may scratch them in, but typically this is either hardly detectable or an exception to the rule. The following, is a partial listing of stones and their hardness classification: 1

Mohs scale of mineral hardness

What is the world's smallest continent?

Hardness - definition of hardness by The Free Dictionary Hardness - definition of hardness by The Free Dictionary http://www.thefreedictionary.com/hardness 1. The quality or condition of being hard. 2. The relative resistance of a mineral to scratching, as measured by the Mohs scale. 3. The relative resistance of a metal or other material to denting, scratching, or bending. hardness n 1. the quality or condition of being hard 2. (Minerals) one of several measures of resistance to indentation, deformation, or abrasion. See Mohs scale , Brinell hardness number 3. (Chemistry) the quality of water that causes it to impair the lathering of soap: caused by the presence of certain calcium salts. Temporary hardness can be removed by boiling whereas permanent hardness cannot hard•ness n. 1. the state or quality of being hard. 2. that quality in water that is imparted by the presence of dissolved salts, esp. calcium sulfate or bicarbonate. 3. the comparative ability of a substance to scratch or be scratched by another. 4. the measured resistance of a metal to indention, abrasion, deformation, or machining. [before 900] hard·ness (härd′nĭs) A measure of how easily a mineral can be scratched. Hardness is measured on the Mohs scale. ThesaurusAntonymsRelated WordsSynonymsLegend: Noun 1. hardness - the property of being rigid and resistant to pressure; not easily scratched; measured on Mohs scale consistency , eubstance , consistence , body - the property of holding together and retaining its shape; "wool has more body than rayon"; "when the dough has enough consistency it is ready to bake" firmness - the property of being unyielding to the touch incompressibility - the property of being incompressible softness - the property of giving little resistance to pressure and being easily cut or molded 2. hardness - a quality of water that contains dissolved mineral salts that prevent soap from lathering; "the costs of reducing hardness depend on the relative amounts of calcium and magnesium compounds that are present" quality - an essential and distinguishing attribute of something or someone; "the quality of mercy is not strained"--Shakespeare 3. callousness , unfeelingness , callosity , insensibility insensitiveness , insensitivity - the inability to respond to affective changes in your interpersonal environment dullness - lack of sensibility; "there was a dullness in his heart"; "without him the dullness of her life crept into her work no matter how she tried to compartmentalize it." 4. hardness - the quality of being difficult to do; "he assigned a series of problems of increasing hardness"; "the ruggedness of his exams caused half the class to fail" difficultness , difficulty - the quality of being difficult; "they agreed about the difficulty of the climb" 5. hardness - excessive sternness; "severity of character"; "the harshness of his punishment was inhuman"; "the rigors of boot camp" hardness noun 2. severity , toughness , callousness , strictness , lack of compassion, sternness , cold-heartedness , hard-heartedness Her hardness is balanced by a goofy humor. hardness 1. (= not softness) [of object, substance, water] → dureza f 2. (= not easiness) [of exam, problem] → dificultad f hardness of hearing → dureza f de oído 3. (= harshness) [of person, measures] → dureza f, severidad f; [of winter, frost] → rigor m hardness of heart → dureza f de corazón , insensibilidad f hardness [ˈhɑːrdnɪs] n [surface, object] → dureté fhard-nosed [ˌhɑːrdˈnəʊzd] adj → impitoyable , dur (e)hard of hearing hard-of-hearing adj to be hard of hearing → être dur (e) d'oreille npl the hard of hearing → les malentendants mplhard porn n → porno m hard hard-pressed [ˌhɑːrdˈprɛst] adj → sous pression to be hard-pressed to do sth → avoir du mal à faire qchhard right n → extrême droite fhard right hard-right modif [party, leader] → d'extrême droite ; [belief, viewpoint] → d'extrême droite hard rock n (MUSIC) → hard rock mhard sell hard-sell n (= aggressive sales pitch) → vente f agressive modif [tactics, approach] → de vente agressive hardness → Härte f (= difficulty) → Schwere f, → Schwierigkeit f; hardness of hearing → Schwerhörigkeit f (= severity) → Härte f; (of winter, frost) → Strenge f; (of light) → Grelle f, → Grellheit f; the hardness of his heart → seine Hartherzigkeit hardness hard (haːd) adjective 1. firm; solid; not easy to break, scratch etc. The ground is too hard to dig. hard قاسٍ твърд duro tvrdý hart hård σκληρός , στέρεος duro ; sólido kõva سفت kova dur קשה कठोर tvr kemény keras harður duro 堅い 단단한 kietas ciets keras hard , stevig hard , fast twardy کلک duro tare твёрдый tvrdý trd trvd hård แข็ง sert , katı 堅硬的 твердий سخت cứng rắn 硬的 2. not easy to do, learn, solve etc. Is English a hard language to learn?; He is a hard man to please. moeilik صَعْب труден difícil nesnadný schwer , schwierig svær δύσκολος difícil raske دشوار vaikea difficile קשה कठिन težak nehéz sulit erfiður difficile 難しい 어려운 sunkus Viņam grūti izpatikt. sukar moeilijk vanskelig trudny کلک difícil dificil трудный ťažký težek težak svår ที่ต้องใช้ความพยายามมาก zor , güç 困難的 важкий, тяжкий مشکل khó 困难的 3. not feeling or showing kindness. a hard master. streng, hardvogtig قاسٍ ، لا يُظْهِرُ مشاعر ودِّيَّهً суров duro přísný hart hård; streng σκληρός , ασυγκίνητος severo ; rudo ; seco karm سختگير kova dur קפדן निष्ठुर neumoljiv, strog rideg bengis strangur duro 無情な 무정한 griežtas, kietas bargs; stingrs tegas hard streng surowy کلک نیول duro dur строгий prísny trd žestok hård[hjärtad], sträng ไม่มีความเมตตา sert , acımasız 冷酷的 суворий ظالم nghiêm khắc 冷酷的 4. (of weather) severe. a hard winter. swaar شَديد، قارِس суров violento tuhý streng hård; streng βαρύς duro , severo , riguroso vali سخت و ناگوار ankara rigoureux קשה दुष्कर oštar, hladan zord ganas, keras harður, erfiður duro , rigido きびしい (날씨가) 험악한 atšiaurus (par laika apstākļiem) bargs teruk streng hard , streng srogi سخت،ګران violento aspru суровый drsný oster oštar hård, sträng, svår (อากาศ) รุนแรง sıkıntılı 惡劣的 суворий شدید khắc nghiệt 恶劣的 5. having or causing suffering. a hard life; hard times. hard, moeilik صَعب، ُمسبب للمِعاناة труден duro těžký hart hård; vanskelig δύσκολος duro , difícil raske طاقت فرسا kova difficile זְמִניים קָשִים कठोर težak, naporan nehéz sulit þungbær, erfiður difficile , duro つらい (생활 등이) 견디기 힘든 sunkus grūts; smags susah hard , zwaar , moeilijk hard , vanskelig ciężki طاقت راښكونكي duro greu тяжёлый ťažký težek težak hård เต็มไปด้วยปัญหา zor , güç 辛苦的 сповнений труднощів і нестатків دشوار gian khổ 艰难的 6. (of water) containing many chemical salts and so not easily forming bubbles when soap is added. The water is hard in this part of the country. hard, brak مليء بالأملاح твърд pesada tvrdý hart hård σκληρός dura kare آهکی؛ سخت kova dur מַיִם קָשִים खारा tvrda (voda) kemény keras kalkríkur, harður duro 硬質の (물이) 경질(硬質)인 kietas (par ūdeni) ciets liat hard hard , kalkrik twarda (o wodzie) کلک،سخت pesada dur жёсткий tvrdý trd tvrd hårt [vatten] ความกระด้างของน้ำ sert , kireçli, acı 硬水 твердий کھارا پانا cứng (nước) 硬水 adverb 1. with great effort. He works very hard; Think hard. hard بِشِدّه، بِصُعوبَه трудно esforçadamente usilovně hart hårdt σκληρά duro , con ahínco kõvasti شديد kovasti dur , sérieusement בְּמַאֲמָץ कठिन jako, naporno komolyan, erősen, keményen keras af fremsta megni, mikið sodo ; attentamente 一生けん命に 열심히 sunkiai, smarkiai, daug grūti; smagi; cītīgi keras hard werken, hard nadenken hardt , flittig ciężko شدید esforçadamente din greu; serios усердно usilovne hudo, trdo, dobro naporno hårt, ordentligt ขยัน çok fazla 努力地 наполегливо, енергійно بڑی جد و جہد سے chăm chỉ 努力地 2. with great force; heavily. Don't hit him too hard; It was raining hard. hard بِقُوَّه، بِقَسْوَه силно violentamente silně, hodně stark hårdt δυνατά fuerte , fuertemente kõvasti محكم kovasti fort , à verse בְּאוֹפן קָשֶה सख्त jako erősen keras ákaflega; fast, hart forte 激しく 세게 smarkiai stipri; spēcīgi kuat hard , zwaar hardt , tungt mocno کلک violentamente tare сильно silno močno jako hårt, häftigt โดยแรง şiddetle, kuvvetle 猛力地 сильно زور سے، طاقت سے mạnh; nặng 猛烈的，重重地 3. with great attention. He stared hard at the man. strak بانتباهٍ شديد внимателно fixamente upřeně anstarren hårdt; strengt επίμονα fijamente tähelepanelikult عمیقاً tiiviisti fixement בֶּקֶשב רָב घूरना uporno, ustrajno feszülten terpusat hvasst, fast intensamente じっと 빤히, 뚫어지게 įdėmiai cieši mendalam met grote aandacht skarpt , strengt , stivt uważnie عميقا،په زوره توګه fixamente fix упорно uprene nepremično pažljivo hårt, stint อย่างเอาจริงเอาจัง büyük dikkatle 極專注地 пильно پوری توجہ سے tập trung 极专注地，紧紧地 4. to the full extent; completely. The car turned hard right. skerp كُلِّيّا напълно totalmente úplně, zcela sehr skarpt εντελώς completamente , totalmente täielikult کاملاً kokonaan à droite toute ככל האפשר पूरा naglo, potpuno teljesen tajam algerlega totalmente 完全に 극도로 tiesiai tuvu klāt sepenuhnya helemaal skarpt zupełnie , całkiem پوره،کاملأ totalmente cu totul круто úplne popolnoma sasvim hårt, häftigt, våldsamt อย่างสมบูรณ์แบบ tam 完全地 повністю بالکل hoàn toàn 完全地 ˈharden verb to make or become hard. Don't touch the toffee till it hardens; Try not to harden your heart against him. verhard, hard maak يَصْلَبُّ، يُصْبِحُ جامِدا втвърдявам endurecer tvrdnout; zatvrdit erhärten blive hård σκληραίνω endurecer kõvaks minema, kõvaks tegema سفت شدن kovettua durcir לְהִתקַשוֹת, לְהַקשוֹת सख्त करना otvrdnuti, okorjeti (meg)keményít mengeras(kan) harðna; herða indurire , diventare insensibile 堅くする 단단하게 하다 sukietėti, sukietinti sacietēt; nocietināt (sirdi) mengeraskan harden gjøre/bli hard, herde stwardnieć , utwardzać كلكول، سختول لكېدل ، سختېدل endurecer a (se) întări затвердевать ; ожесточаться tvrdnúť; zatvrdiť sa strditi (se), utrditi stvrdnuti hårdna, förhärda [sig] ทำให้แข็ง; ทำให้ใจแข็ง sertleş(tir)mek (使)變硬 ставати твердим, тверднути سخت ہو جانا یا کرنا trở nên cứng rắn, mạnh mẽ 使变硬 ˈhardness noun hardheid صُعوبَه، صلابَه، قَسْوَه твърдост dureza tvrdost die Härte hårdhed; strenghed σκληρότητα dureza , firmeza karmus سختی kovuus dureté קושי कड़ापन tvrdoca, okrutnost keménység kekerasan harka durezza 堅さ 단단함 kietumas, sunkumas cietība; grūtums; smagums; bargums kekerasan hardheid hardhet ; strenghet wytrzymałość , odporność كلكوالى dureza duritate твердость ; жесткость tvrdosť trdota stvrdnutost hårdhet ความแข็ง sertlik, katılık 硬度 твердість; міцність سختی sự cứng rắn 硬度 ˈhardship noun (something which causes) pain, suffering etc. a life full of hardship. teenspoed, swaarkry صُعوبَة، ألَم، مُعاناه мъка dureza utrpení die Mühsal modgang κακουχία apuro ; infortunio ; prueba ; privación viletsus مشقت vastoinkäyminen épreuve קושי कठिनाई, विपत्ति teškoca, nevolja nehézség kesulitan erfiðleikar, hrakningar stento 苦難 고난, 역경 sunkumai grūtības kesusahan lijden lidelser , strabaser , motgang trud , niedostatek ستونځه، مشكلات، ربړه،سختى dureza în­cer­cări; greutăţi невзгоды utrpenie stiska, trpljenje tegoba vedermöda, strapats, umbärande ความทุกข์ยาก zorluk (造成)痛苦、磨難 труднощі, нужда پریشانیاں sự gian khổ 苦难 ˈhard-and-fast adjective (of rules) that can never be changed or ignored. vas, bindend بإحْكام، لا يُمْكِن تَجاهُلُه вечен inflexível striktní starr ufravigelig άκαμπτος , απαρέγκλιτος definitivo , irrevocable range سفت و سخت tiukka strict כְּלָלִים נוּקשִׁים पक्का ustaljeno (pravilo) szigorú pasti ósveigjanlegur ferreo , rigido 厳重な 변경을 허락치 않는 tvirtai nustatytas, griežtas (par likumu) negrozāms peraturan yang boleh diabaikan vuurvast , ijzeren unyansert , fast nienaruszalny سخت inflexível strict неукоснительный pevný, záväzný trden nepromenljiv fastslagen, järnhård, orubblig (กฎ) ตายตัว değişmez, katı (規定)不容變通的 раз і назавжди встановлений معیّن cứng rắn, chặt chẽ 不容变通的 ˈhard-back noun a book with a hard cover. Hard-backs are more expensive than paperbacks. hardeband غِلاف قاسٍ أو مُقَوّى твърда корица livro encadernado vázaná kniha fester Einband indbundet bog δεμένο βιβλίο de tapas duras kõvade kaantega raamat كتاب با جلد زخيم kovakantinen kirja livre relié כְּרִיכָה קָשָה कड़े कवर वाली पुस्तक knjiga u tvrdom uvezu kemény kötésű sampul keras innbundinn bók (í stinn spjöld) (libro con copertina rigida) 堅表紙の 표지가 단단한 책 knyga kietais viršeliais (cietos vākos) iesieta grāmata buku berkulit keras harde omslag, harde cover innbundet bok książka w twardej oprawie د زخيم جلد لرونكي كتاب livro encadernado carte/volum cartonat(ă) книга в твёрдом переплёте kniha v tvrdej väzbe knjiga v trdi vezavi tvrd povez inbunden bok หนังสือปกแข็ง ciltli kitap 精裝本 книга в твердій палітурці مجلد کتاب sách bìa cứng 硬书皮的书，精装书 ˌhard-ˈboiled adjective (of eggs) boiled until the white and the yolk are solid. hardgekook مَسْلوق جَيدا твърдосварен duro natvrdo hartgekocht hårdkogt σφιχτοβρασμένος duro , cocido kõvaks keedetud سفت شده kovaksikeitetty dur בֵּיצָה קָשָה उबला हुआ tvrdo kuhan (jaje) kemény (tojás) matang harðsoðinn sodo 堅ゆでの (계란 등이) 단단하게 삶은 kietai virtas (par olu) cieti novārīta telur masak hardgekookt hardkokt (ugotowany) na twardo سختول duro (ou fiert) tare сваренный вкрутую natvrdo trdo kuhan tvrdo kuvan hårdkokt (ไข่) ต้มสุก lop , katı (雞蛋)完全煮熟的 крутий پوری طرح ابلا انڈا luộc chín (trứng) （鸡蛋）煮得老的 hardˈdisk noun a device that is fixed inside a computer and is used for storing information. hardeskyf القُرص الصَّلْب في الكومبيوتر твърд диск disco rígido hard disk, pevný disk der Harddisk harddisk σκληρός δίσκος disco duro kõvaketas حافظه ثابت kiintolevy disque dur דִיסְק קָשִיח कंप्यूटर हार्ड डिस्क जिसमें कंप्यूटर में डाटा सेव होता है या करते हैं hard-disk merevlemez hard disk disco rigido*, hard disk ハードディスク 하드 디스크 kietasis diskas cietais disks cakera keras harddisk harddisk هارددسک жёсткий диск pevný disk trdi disk hard disk hårddisk จานแม่เหล็กเก็บข้อมูลของคอมพิวเตอร์ disk , sabit disk 硬碟 твердий диск بڑے گھیر کی مقناطیسی قرص یا تھالی جس میں زیادہ معلومات ذخیرہ ہو سکیں đĩa cứng 硬盘 ˈhard-earned adjective earned by hard work or with difficulty. I deserve every penny of my hard-earned wages. swaar verdiende مُكْتَسَب بِالعَمَل الصَّعْب спечелен с труд ganho a custo těžce zasloužený hart verdient hårdt tjent αποκτημένος με κόπο ganado con el sudor de la frente ränga tööga teenitud به زحمت كسب شده kovalla työllä ansaittu bien mérité עָמַל רַב परिश्रम का धन teško zaraden nehezen megkeresett hasil kerja keras sem e-r hefur unnið til (guadagnato con grande fatica) 苦心して得た 애써서 얻은 sunkiai uždirbtas grūti nopelnīts hasil kerja keras zuurverdiend surt ervervet , dyrekjøpt ciężko zapracowany په زحمت کی نیول ganho a custo câştigat cu greu с трудом заработанный ťažko zarobený težko zaslužen teško zarađen surt (med möda) förtjänad ทำงานหนัก zorlukla kazanılmış 辛苦掙得的 зароблений тяжкою працею مہنت کی کمائی kiếm được một cách khó khăn 辛苦挣得的 ˌhard-ˈheaded adjective practical; shrewd; not influenced by emotion. a hard-headed businessman. nugter, prakties عَنيد الرأي، صَلْب، غَير عاطِفي практичен pragmático praktický, věcný, realistický nüchtern nøgtern πρακτικός , χωρίς ευαισθησίες práctico , realista kaine mõistusega سر سخت kylmäpäinen pratique עקשן शातिर realistican, praktican, nesentimentalan gyakorlatias pintar, keras kepala harðskeyttur, séður pratico 実際的な 완고한 blaivaus proto, praktiškas, dalykiškas praktisks; lietišķs berjiwa kental hard praktisk , sta , stri trzeźwy , praktyczny , wyrachowany سر سخت prático practic; pragmatic практичный rozumný; vecný; triezvy praktičen, razumarski trezven praktisk, förslagen, nyktert tänkande ฉลาด duygularına kapılmayan 講求實際的，精明的，不感情用事的 практичний, тверезий عمل سے نہ کہ جذبات سے کام لینے والا، شاطر thực tế 讲实际的，头脑冷静的 ˌhard-ˈhearted adjective not feeling or showing pity or kindness. a hard-hearted employer. hardvogtig, verhard قاسي القَلْب коравосърдечен insensível nemilosrdný hartherzig hårdhjertet σκληρός , σκληρόκαρδος de corazón duro como una piedra, insensible kõva südamega سنگدل kovasydäminen impitoyable קשוח निर्दयी tvrda srca, okrutan kemény szívű kejam harðbrjósta insensibile , spietato 無情な 무정한 kietaširdis cietsirdīgs; nežēlīgs tiada belas kasihan hardvochtig hardhjertet bezwzględny په زړه كلك،په زړه سخت، بې زړه سو يه insensível nemilos жестокосердный nemilosrdný, bezcitný trdosrčen bezdušan hårdhjärtad ดันทุรัง katı kalpli, kalpsiz 冷酷的 безсердечний; черствий سخت دل، ظالم cứng rắn 冷酷的 ˈhardware noun 1. metal goods such as pots, tools etc. This shop sells hardware. hardeware, ysterware أدوات مَعدَنيَّه، أسْلِحَه железария ferragens železářské zboží die Eisenwaren isenkram είδη κιγκαλερίας ferretería rauakaup ظروف فلزي rautatavara quincaillerie כֵּלי בָּיִת וְגָן लोहे का सामान željezna roba, željezarija vasáru barang-barang dari logam járnvara ferramenta , articoli di ferro 金物類 금속 제품 metalo dirbiniai dzelzs izstrādājumi; saimniecības preces perkakasan hardware jernvarer towary żelazne فلزی ظروف ferragens (articol de) fierărie скобяные изделия železiarsky tovar železnina; strojna oprema gvožđarija järn-, metall-, smidesvaror เครื่องมือที่ทำด้วยเหล็ก hırdavat , madenî eşya 五金 металеві вироби دھات کے اوزار یا گھریلو سامان đồ ngũ kim 金属器具 2. the mechanical parts of a computer. apparatuur الأجزاء الميكانيكيّه في الكومبيوتر، جِسْم الكومبيوتر хардуер hardware hardware die Hardware hardware εξαρτήματα Η/Υ hardware , soporte físico riistvara سخت افزار laitteisto hardware חוֹמְרָה कंप्यूटर के पाटर्स hardver, tehnicka oprema kompjutera hardver hardware, perangkat keras hardware （コンピューターの）機器 하드웨어 techninė kompiuterio įranga (datora) aparatūra perkakasan hardware maskinvare sprzęt komputerowy هاردویر аппаратное обеспечение technické vybavenie (počítača) železnina; strojna oprema hardver hårdvara อุปกรณ์คอมพิวเตอร์ donanım 電腦硬體 апаратура کمپیوٹر کے کل پرزے phần cứng （电脑的）硬件 ˌhard-ˈwearing adjective that will not wear out easily. a hard-wearing fabric. sterk, duursaam لا يَبْلى بِسُهولَه траен resistente trvanlivý zermürbend slidstærk ανθεκτικός resistente vastupidav بادوام kulutusta kestävä solide עמיד टिकाऊ izdržljiv (materijal) tartós awet endingargóður, slitþolinn resistente 長持ちする 쉽게 닳지 않는 patvarus, gerai dėvimas ilgi valkājams tidak mudah koyak stevig , solide , bestand tegen slijt slitesterk , solid mocny , odporny na zużycie مقاوم resistente rezistent ноский trvanlivý odporen trajan slitstark (ผ้า) เนื้อหยาบ kolay eskimez 耐磨損的 зносостійкий پائیدار ، مضبوط ، بہت چلنے والا bền 耐磨损的 be hard on 1. to punish or criticize severely. Don't be too hard on the boy – he's too young to know that he was doing wrong. streng/straf behandel يُعاقِب أو يَنْتَقِد بِقَسْوَه наказвам сурово ser duro com být tvrdý na streng behandeln være hård ved είμαι αυστηρός απέναντι σε κπ., τιμωρώ ser duro/severo con karm olema با خشونت رفتار کردن olla ankara être dur avec לְהַחמִיר עִם कठोरता दिखाना biti prestrog prema nekomu szigorú (vkivel) keras vera strangur við essere duro con つらく当たる 심하게 벌주다 būti griežtam su sodīt; kritizēt tegas zwaar straffen; streng bekritiseren; iemand hard vallen være hard/slem mot być surowym dla په خشونت کی رفتار کول ser duro com a fi dur cu быть слишком строгим byť tvrdý na biti strog z biti surov vara hård mot กระทำรุนแรงกับ acımasızlık etmek, insafsız/zalim olmak 嚴厲懲罰或批評 суворий до кого سختی سے سزا دینے phạt hoặc chỉ trích nghiêm khắc 过分严厉地对待某人 2. to be unfair to. If you punish all the children for the broken window it's a bit hard on those who had nothing to do with it. hard, onregverdig يَقْسو عَلى، يُعامِل بِقَسْوَه не съм справедлив ser injusto být nespravedlivý k ungerecht behandeln uretfærdig είμαι άδικος για ser injusto con ebaõiglane olema غیرمنصفانه بودن olla epäreilu injuste envers לִהיוֹת לֹא הוֹגֶן כְּלָפֵּי जुल्म ne biti fer igazságtalan tidak adil ósanngjarn essere ingiusto con きびしすぎる 모질게 굴다 būti neteisingam kieno nors atžvilgiu būt netaisnam tidak adil onrechtvaardig zijn tegen skjære alle over én kam być niesprawiedliwym w stosunku do بی انصافی ser injusto a fi nedrept cu быть несправедливым byť nespravodlivý k biti krivično do ne biti fer vara hårt mot ทำโทษ; ติเตียน insafsızlık etmek 不公平地對待 несправедливий до кого نا انصافی کرنا không công bằng 不公平地对待 hard at it busy doing (something). I've been hard at it all day, trying to get this report finished. werk hard daaraan مَشْغول جِداً зает atarefado zapřažený sich abrackern være travl ριγμένος με τα μούτρα (στη δουλειά) liado/ocupado/atareado con algo tööhoos سخت مشغول كاري بودن työskennellä tiiviisti attelé à (qqch.) לַעֲבוֹד קָשֶה व्यस्त रहना naporno raditi keményen (csinál vmit) sibuk vera á fullu lavorato sodo 精を出して 전념하다 sunkiai, neatsitraukiant dirbantis aizņemts (kaut ko darot) sibuk melakukan sesuatu hard bezig zijn (arbeide) hardt/flittig ciężko pracujący, zapracowany په يوه كار باندي سخت مصروفيدل atarefado ocupat cu ceva усердно трудиться zaneprázdnený vprežen v (delo) zauzet slita hårt med ไม่ว่าง harıl harıl çalışarak, tüm gücüyle çalışarak 忙著做(某事) зайнятий کسی چیز میں مشغول ہونا bận bịu 忙于作（某事） hard done by unfairly treated. You should complain to the headmaster if you feel hard done by. word stief behandel مُعامَل مُعامَلَةً غَيْر عادِلَه несправедливо третиран injustiçado ukřivděný špatným zacházením ungerecht behandeln uretfærdigt behandlet αδικημένος, ριγμένος tratado injustamente ülekohut kannatama ناعادلانه برخود شده kaltoin kohdeltu injustement traité עוֹבֵד קָשֶה מִדָי अनुचित व्यवहार करना biti zakinut igazságtalanul bánnak vkivel diperlakukan tidak adil sem illa er komið fram við trattato ingiustamente 不当に扱われて 부당하게 대우하는 nuskriaustas [] netaisnu izturēšanos diperlakukan dengan tidak adil onrechtvaardig behandeld urettferdig behandlet niesprawiedliwie potraktowany په درغلۍ،په بياوۍ injustiçado tratat incorect/nedrept обделённый zle zaobchádzať s nepravilno obravnavan nefer tretiran orättvist behandlad กระทำโดยมิชอบ haksızlığa uğrama, haksızlık edilme 受到不公平對待 такий, що зазнає несправедливого ставлення نا انصافی کرنا bị đối xử không công bằng 受到不公平对待 hard lines/luck bad luck. Hard lines/luck! I'm afraid you haven't won this time; It's hard luck that he broke his leg. 'n jammerte حَظٌّ سَيِّء лош късмет azar smůla Pech! bare ærgerligt ατυχία mala suerte , mala pata ei vedanud بد شانسی huono onni pas de chance מָזַל בִּיש बदकिस्मती zla sreca, peh balszerencse sial óheppni sfortuna 不運 참 안됐다 gaila, nepasisekė neveiksme nasib tidak baik pech , ongeluk motgang , dårlig lykke pech بد بخت azar невезенье smola zla usoda, smola loša sreća hårda bud โชคร้าย şanssızlık, talihsizlik 運氣不好 тяжка доля خراب قسمت thật không may 坏运气 hard of hearing rather deaf. He is a bit hard of hearing now. hardhorend wees ثَقيل السَّمَع глух surdo nedoslýchavý schwerhörig halvdøv; tunghør βαρήκοος duro de oído kõva kuulmisega تقریباً کر huonokuuloinen dur d'oreille כְּבָד שְׁמִיעָה कम सुनना nagluh nagyothalló agak tuli heyrnarskertur, heyrir illa duro d'orecchi 耳が遠い 귀가 어두운 neprigirdintis pakurls hampir pekak hardhorend tunghørt przygłuchawy كوڼ duro de ouvido tare de ureche тугоухий nahluchlý naglušen gluv lomhörd ไม่ค่อยได้ยิน ağır işiten 幾乎沒有聽力 глухуватий بہراپن، اونچا سننا nặng tai 听觉不灵的，有点耳聋的 a hard time (of it) trouble, difficulty, worry etc. The audience gave the speaker a hard time of it at the meeting; The speaker had a hard time (of it) trying to make himself heard. 'n moeilike tyd, 'n swaar tyd مَتاعِب، وَقْتٌ صَعْب проблем momentos difíceis krušné chvíle; potíže schwere Zeit problemer δυσκολίες, βάσανα un mal rato raskustes مشکل؛ نگرانی hankaluudet du fil à retordre קושי मुश्किल teškoce (neugodnosti), teška vremena „megpróbáltatás” kesulitan í erfiðleikum, eiga erfitt (del filo da torcere) つらいめ 곤욕 rūpesčiai, sunkumai grūtības; raizes sukar het moeilijk maken voor; iemand moeilijk vallen vanskelighet , trøbbel przeprawa, trudności z استونځی momentos difíceis de furcă тяжёлый момент ťažkosti preglavice, težave poteškoća fullt upp เวลาที่ยาก zorluk , güçlük 麻煩，困難，煩擾 тяжкі часи پریشانیاں کھڑی کرنا gặp khó khăn 受苦，困难 hard up not having much especially money. I'm a bit hard up at the moment; I'm hard up for envelopes. platsak wees, geldnood hê في وَضْع مادي صَعْب، لا يوجد لَدَيه مال на червено com falta de na suchu; úplně bez (peněz) knapp mit Geld etc. hårdt spændt for; i bekneb είμαι αδέκαρος, μου έχει τελειώσει κτ. estar sin blanca/sin un duro; estar casi sin algo näpud põhjas در مضيقه tiukilla avoir grand besoin בִּמצוּקָה כַּספִּית तंगी bez novaca, u financijskim neprilikama rosszul áll tidak punya í kröggum, blankur (al verde), (a corto di quattrini) 欠乏している 돈에 몹시 궁한 (kam) striuka su (pinigais) [] grūtībās memerlukan blut , bijna door iets heen zijn i pengeknipe ; mangle noe być spłukanym په استونځی com muita falta de strâmtorat; lipsit de нуждающийся vo finančnej tiesni; nemať (čo) na tesnem (z denarjem) u oskudici dåligt ställt, ont om ขาดแคลนเงิน parasız, yolsuz 短缺(尤指金錢)，缺錢 в скрутному становищі پیسوں کی قلت ہونا cạn túi （钱）不多，缺钱

i don't know

Which gas forms approximately 1% of the atmosphere?

Introduction to the Atmosphere: Background Material Introduction to the Atmosphere This section provides a brief overview of the properties associated with the atmosphere. The general concepts found in this section are: The earth's atmosphere is a very thin layer wrapped around a very large planet. Two gases make up the bulk of the earth's atmosphere: nitrogen ( ), which comprises 78% of the atmosphere, and oxygen ( ), which accounts for 21%. Various trace gases make up the remainder. Based on temperature, the atmosphere is divided into four layers: the troposphere, stratosphere, mesosphere, and thermosphere. Energy is transferred between the earth's surface and the atmosphere via conduction, convection, and radiation. Ocean currents play a significant role in transferring this heat poleward. Major currents, such as the northward flowing Gulf Stream, transport tremendous amounts of heat poleward and contribute to the development of many types of weather phenomena. This section includes seven classroom activities. Atmospheric Properties The thin envelope of air that surrounds our planet is a mixture of gases, each with its own physical properties. The mixture is far from evenly divided. Two elements, nitrogen and oxygen, make up 99% of the volume of air. The other 1% is composed of "trace" gases, the most prevalent of which is the inert gaseous element argon. The rest of the trace gases, although present in only minute amounts, are very important to life on earth. Two in particular, carbon dioxide and ozone, can have a large impact on atmospheric processes. Another gas, water vapor, also exists in small amounts. It varies in concentration from being almost non-existent over desert regions to about 4% over the oceans. Water vapor is important to weather production since it exists in gaseous, liquid, and solid phases and absorbs radiant energy from the earth. Structure of the Atmosphere The atmosphere is divided vertically into four layers based on temperature: the troposphere, stratosphere, mesosphere, and thermosphere. Throughout the Cycles unit, we'll focus primarily on the layer in which we live - the troposphere. Troposphere The word troposphere comes from tropein, meaning to turn or change. All of the earth's weather occurs in the troposphere. The troposphere has the following characteristics. It extends from the earth's surface to an average of 12 km (7 miles). The pressure ranges from 1000 to 200 millibars (29.92 in. to 5.92 in.). The temperature generally decreases with increasing height up to the tropopause (top of the troposphere); this is near 200 millibars or 36,000 ft. The temperature averages 15°C (59°F) near the surface and -57°C (-71°F) at the tropopause. The layer ends at the point where temperature no longer varies with height. This area, known as the tropopause, marks the transition to the stratosphere. Winds increase with height up to the jet stream. The moisture concentration decreases with height up to the tropopause. The air is much drier above the tropopause, in the stratosphere. The sun's heat that warms the earth's surface is transported upwards largely by convection and is mixed by updrafts and downdrafts. The troposphere is 70% Atmospheric Processes Interactions - Atmosphere and Ocean In the Cycles overview, we learned that water is an essential part of the earth's system. The oceans cover nearly three-quarters of the earth's surface and play an important role in exchanging and transporting heat and moisture in the atmosphere. Most of the water vapor in the atmosphere comes from the oceans. Most of the precipitation falling over land finds its way back to oceans. About two-thirds returns to the atmosphere via the water cycle. You may have figured out by now that the oceans and atmosphere interact extensively. Oceans not only act as an abundant moisture source for the atmosphere but also as a heat source and sink (storage). The exchange of heat and moisture has profound effects on atmospheric processes near and over the oceans. Ocean currents play a significant role in transferring this heat poleward. Major currents, such as the northward flowing Gulf Stream, transport tremendous amounts of heat poleward and contribute to the development of many types of weather phenomena. They also warm the climate of nearby locations. Conversely, cold southward flowing currents, such as the California current, cool the climate of nearby locations. Energy Heat Transfer Practically all of the energy that reaches the earth comes from the sun. Intercepted first by the atmosphere, a small part is directly absorbed, particularly by certain gases such as ozone and water vapor. Some energy is also reflected back to space by clouds and the earth's surface. Energy is transferred between the earth's surface and the atmosphere via conduction, convection, and radiation. Conduction is the process by which heat energy is transmitted through contact with neighboring molecules. Some solids, such as metals, are good conductors of heat while others, such as wood, are poor conductors. Air and water are relatively poor conductors. Since air is a poor conductor, most energy transfer by conduction occurs right at the earth's surface. At night, the ground cools and the cold ground conducts heat away from the adjacent air. During the day, solar radiation heats the ground, which heats the air next to it by conduction. Convection transmits heat by transporting groups of molecules from place to place within a substance. Convection occurs in fluids such as water and air, which move freely. In the atmosphere, convection includes large- and small-scale rising and sinking of air masses and smaller air parcels. These vertical motions effectively distribute heat and moisture throughout the atmospheric column and contribute to cloud and storm development (where rising motion occurs) and dissipation (where sinking motion occurs). To understand the convection cells that distribute heat over the whole earth, let's consider a simplified, smooth earth with no land/sea interactions and a slow rotation. Under these conditions, the equator is warmed by the sun more than the poles. The warm, light air at the equator rises and spreads northward and southward, and the cool dense air at the poles sinks and spreads toward the equator. As a result, two convection cells are formed. Meanwhile, the slow rotation of the earth toward the east causes the air to be deflected toward the right in the northern hemisphere and toward the left in the southern hemisphere. This deflection of the wind by the earth's rotation is known as the Coriolis effect. Radiation is the transfer of heat energy without the involvement of a physical substance in the transmission. Radiation can transmit heat through a vacuum. Energy travels from the sun to the earth by means of electromagnetic waves. The shorter the wavelength, the higher the energy associated with it. This is demonstrated in the animation below. As the drill's revolutions per minute (RPMs) increase, the number of waves generated on the string increases, as does the oscillation rate. The same principle applies to electromagnetic waves from the sun, where shorter wavelength radiation has higher energy than longer wavelength radiation. Most of the sun's radiant energy is concentrated in the visible and near-visible portions of the spectrum. Shorter-than-visible wavelengths account for a small percentage of the total but are extremely important because they have much higher energy. These are known as ultraviolet wavelengths. Concluding Thoughts The physical and chemical structure of the atmosphere, the way that the gases interact with solar energy, and the physical and chemical interactions between the atmosphere, land, and oceans all combine to make the atmosphere an integral part of the global biosphere. For students to truly understand the nature and importance of the atmosphere, they should understand the answers to these questions: What is the structure and composition of the atmosphere? How does solar energy influence the atmosphere? How does the atmosphere interact with land and oceans? How is heat transferred throughout the earth system? Activities

Argon

What is the term for the energy obtained from hot, underground rocks?

Atmosphere | Atmospheric Gases | Aerosols | Greenhouse Gases Atmospheric Composition Air Air is a mixture of gases and aerosols that composes the atmosphere surrounding Earth. The primary gases of air include nitrogen (78%) and oxygen (21%). Trace gases and aerosols make up the remaining 1% of air. The trace gases include the noble gases argon, neon, helium, krypton and xenon; hydrogen; and the greenhouse gases. The aerosols are solid or liquid particles having diameters in the region of 0.001 to 10 microns (millionth of a metre), and include dust, soot, sea salt crystals, spores, bacteria, viruses and a plethora of other microscopic particles, which may be natural or man-made. Earth maintains an atmosphere through its gravitational pull. Consequently, most air is found in the lowest 10 kilometres of the atmosphere. Experienced mountain climbers are aware of how thin the air becomes, and may carry oxygen tanks to assist breathing at high altitudes. Within the lower atmosphere, however, air remains remarkably uniform in composition, as a result of efficient recycling processes and turbulent mixing in the atmosphere. Atmospheric Gases There are a number of atmospheric gases which make up air. The main gases are nitrogen and oxygen, which make up 78% and 21% of the volume of air respectively. Oxygen is utilised primarily by animals, including humans, but also to a small degree by plants, in the process of respiration (the metabolism of food products to generate energy). The remaining 1% of the atmospheric gases is made up of trace gases. These include the noble gases, very inert or unreactive gases, of which the most abundant is argon. Other noble gases include neon, helium, krypton and xenon. Hydrogen is also present in trace quantities in the atmosphere, but because it is so light, over time much of it has escaped Earth's gravitational pull to space. The remaining trace gases include the greenhouse gases, carbon dioxide, methane, nitrous oxide, water vapour and ozone, so-called because they are involved in the Earth natural greenhouse effect which keeps the planet warmer than it would be without an atmosphere. Oxygen The gas oxygen (O 2 ), composed of molecules of two oxygen atoms, occupies 21% of the Earth's atmosphere by volume. It is colorless, odorless, and tasteless. Oxygen also comprises 86% of the oceans and 60% of the human body, and is the third most abundant element found in the Sun. Almost all plants and animals require oxygen for respiration to maintain life. Oxygen is very reactive and oxides of most elements are known. A chemical reaction in which an oxide is formed is known as oxidation. The rate at which oxidation occurs varies with the element with which oxygen is reacting. Rust, or iron oxide, for example forms relatively slowly, over days or weeks. Burning or combustion, however, involves a very rapid oxidation. Carbon in fossil fuels, for example, can be quickly oxidised to carbon monoxide and carbon dioxide, with a considerable amount of heat being given off. We can convert this heat into useful energy for heating, electricity and locomotion. Within the stratosphere, oxygen molecules combine with free oxygen atoms to form ozone (O 3 ). Ozone absorbs ultraviolet (UV) radiation from the Sun, and protects life on Earth from its damaging effect. Although abundant between 19 and 30 km altitude, the air at these levels in the atmosphere is thin. If all the ozone in the stratosphere was compressed to ordinary atmosphere pressure at ground level, it would occupy a layer only 3 mm thick. Nitrogen The gas nitrogen (N 2 ), composed of molecules of two nitrogen atoms, occupies 78% of the Earth's atmosphere. It is colorless, odorless, and tasteless. Nitrogen is as important as it is common. It's essential to the nutrition of plants and animals. Nitrogen is a constituent in all proteins and in the genetic material (DNA) in all organisms. The low content of nitrogen in most soils exists in stark contrast to the abundance of nitrogen in air. This is because gaseous nitrogen molecules have very strong bonds linking the atoms together, making the gas chemically stable and unusable by most biological organisms. Some species of bacteria absorb nitrogen from the air and convert it into ammonium, which plants can use. This process, called nitrogen fixation, is the principal natural means by which atmospheric nitrogen is added to the soil. Legumes, such as beans, can fix nitrogen from the atmosphere. This is accomplished by nitrogen-fixing bacteria living in nodules on the plant roots. Nitrogen molecules in the atmosphere can also be broken by the energy generated by lightning strikes and volcanic action. Whenever lightning flashes in the atmosphere, some nitrogen combines with oxygen and forms the gas nitric oxide (NO). This nitric oxide is converted to nitric acid, which is highly soluble in water and falls to the ground in rainwater, to be absorbed by soils. Globally, however, nitrogen-fixing bacteria are a far more significant source of fixed nitrogen. Trace Gases Most of our atmosphere is made up of nitrogen (78% by volume) and oxygen (21% by volume). The remaining 1% of the atmospheric gases are known as trace gases because they are present in such small concentrations. The most abundant of the trace gases is the noble gas argon (approximately 1% by volume). Noble gases, which also include neon, helium, krypton and xenon, are very inert and do not generally engage in any chemical transformation within the atmosphere. Hydrogen is also present in trace quantities in the atmosphere, but because it is so light, over time much of it has escaped Earth's gravitational pull to space. Despite their relative scarcity, the most important trace gases in the Earth's atmosphere are the greenhouse gases. Most abundant in the troposphere, these gases include carbon dioxide, methane, nitrous oxide, water vapour and ozone, so-called because they are involved in the Earth natural greenhouse effect which keeps the planet warmer than it would be without an atmosphere. Apart from water vapour, the most abundant greenhouse gas (by volume) is carbon dioxide. Despite being present in only 380 parts per million by volume of air, carbon dioxide and the other greenhouse gases help to keep the Earth 33�C warmer than it would otherwise be without an atmosphere. Through emissions of greenhouse gases however, mankind has enhanced with natural greenhouse effect which may now be leading to a warming of the Earth climate. Whilst ozone behaves like a greenhouse gas in the troposphere, in the stratosphere where its abundance is most significant within the ozone layer, it helps to filter out the incoming ultraviolet radiation from the Sun, protecting life on Earth from its harmful effects. Air within the stratosphere is thin however. If all the ozone in the stratosphere was compressed to ordinary atmosphere pressure at ground level, it would occupy a layer only 3 mm thick. Other trace gases in the atmosphere arise from natural phenomena such as volcanic eruptions, lightning strikes and forest fires. Gases from these sources include nitric oxide (NO) and sulphur dioxide (SO 2 ). In addition to natural sources of nitric oxide and sulphur dioxide there are now many man-made sources, including pollutant emissions from cars, agriculture and electricity generation through the burning of fossil fuels. During the 20th century other man-made processes have put completely new trace gases into the atmosphere, for example the chlorofluorocarbons (CFCs) which damage the ozone layer. Aerosols Aerosols are solid or liquid particles dispersed in the air, and include dust, soot, sea salt crystals, spores, bacteria, viruses and a plethora of other microscopic particles. Collectively, they are often regarded as air pollution, but many of the aerosols have a natural origin. They are conventionally defined as those particles suspended in air having diameters in the region of 0.001 to 10 microns (millionth of a metre). They are formed by the dispersal of material at the surface (primary aerosols), or by reaction of gases in the atmosphere (secondary aerosols). Primary aerosols include volcanic dust, organic materials from biomass burning, soot from combustion and mineral dust from wind-blown processes. Secondary aerosols include sulphates from the oxidation of sulphur-containing gases during the burning of fossil fuels, nitrates from gaseous nitrogen species, and products from the oxidation of volatile organic compounds (VOCs). Although making up only 1 part in a billion of the mass of the atmosphere, they have the potential to significantly influence the amount of sunlight that reaches the Earth�s surface, and therefore the Earth's climate. Although the abundance of aerosols varies over short time scales, for example after a volcanic eruption, over the long term the atmosphere is naturally cleansed through mixing processes and rainfall. Cleansing is never complete however, and there exists a natural background level of aerosols in the atmosphere. The average time spent in the atmosphere by aerosols is dependent upon their physical and chemical characteristics, and the time and location of their release. Natural sources of aerosols are probably 4 to 5 times larger than man-made ones on a global scale, but regional variations of man-made aerosol emissions may change this ratio significantly in certain areas, particularly in the industrialised Northern Hemisphere. At certain times of the year, the natural background level of aerosols may increase, for example, during the growing season, when large quantities of pollen are released into the atmosphere.

i don't know

What name is given to the rocks swallowed by dinosaurs to assist their digestion?

Dinosaurs 118 Final - Science 118 with Oliver at Worcester State College - StudyBlue Who was the last Ptolemaic Pharaoh? Cleopatra Which of the Greek elements was the lightest? Fire The fall of what city was the ultimate (albeit distant) justification given for the first crusade? Jerusalem When did the universe begin (roughly)? 14 billion years ago Who was the tutor of Alexander, Prince of Macedon? Aristotle Identify the scientist associated with: Astrology Ptolemy What Greek city is the home of the Pythian Oracle of Apollo? Delphi The statement "We can't prove Aliens didn't build the pyramids, therefore they did" is an example of the appeal to stupidity. True or False? False An appeal to authority is legitimate if 1) The authority is an expert in the area of knowledge under consideration; and 2) The statement of the authority concerns his or her area of mastery; and 3) You happen to like the experts point of view. True or False? False If we pass laws against fully-automatic weapons, then it won't be long before we pass laws on all weapons, and then we will begin to restrict other rights, and finally we will end up living in a communist state. Thus we should not ban fully automatic weapons. What kind of argument is this? A slippery slope argument The argument fallacy hat means attacking the person instead of the argument is: Ad hominem Anecdotes are valid evidence. True or False? False "Science is built of facts the way a house if built of bricks; but an accumulation of facts is no more science than a pile of bricks is a house." - Who said this? Henri Poincaire Tautaology, circular reasoning, and 'avoiding the question' all mean the same thing. True or False? False Treating a complex issue as if there are only two, polar opposite choices is called: False Dichotomy 'Circular reasoning' is using a restatement of your conclusions as your premise. True or False? True What is the term for a faulty logical argument? Fallacious The fallacy occurs when we selectively focus on the evidence which tends to make our case while ignoring counter-examples is called: Confirmation Bias The fallacy of exclusion violates the total evidence principle. True or False? True Statement 1: All squares are rectangles. This is a square, therefore it is a rectangle. Statement 2: This is a rectangle, therefore it is a square. Statement 2 is an example of a: Non-reciprocal syllogism If, because we don't know something DIDN'T happen, we can conclude that it DID happen, then we have committed the appeal to: Ignorance Using 'expert' testimony to make your case is called; Appeal to Authority Dr. Oliver's observation that "people don't usually answer the question they are being asked" is known as 'avoiding the question.' True or False? True The latin term for a conclusion that "doesn't follow' from a premise is; Non sequitur Using an unrelated argument to distract from the case being debated is called a; Red Herring What Family includes leopards and domestic cats? Felidae According to the concept of punctuated equilibrium, a new species accumulates most of its unique features as it comes into existence Who is the creator of the cladistic method? Willi Hennig Is only found in only one group AND all members of the group possess it What order contains dogs, cats, bears, and weasels? Carnivora Sabertooth mammals are a _______ assemblage? Polyphyletic What term means a clade derived from multiple ancestors? Polyphyly The defininf character of the Vertebrata is Vertebrae The biological species concept is inadequate for grouping asexual organisms What group lost their eyes, and later re-evolved them? Snakes Chordates do not include what... echinoderms The term that is most appropriately associated with clade is... monophyletic If flight is a character used to group two distantly related organisms, it would be what kind of trait? Homoplastic Who wrote the book "Zoonomia" proposing evolution? Darwin's grandfather, Erasmus Darwin A tentative explanation that can be tested and is falsifiable. Who wrote the Essay on Population that so affected Darwin's thinking? Thomas Malthus What primate species is our closest living relative? Chimpanzee Horses stand on the (modified) nail of the third digit. True or False? True What does the H.M.S. stand for in H.M.S. Beagle? His (Her) Majesty's Ship The French naturalist Lamarck argued what idea? Species evolve, and the characteristcs an individual develops as a result of using or not using its native capacities can be passed to its young What book was written by William Paley to explain the appeal to design? Natural Theology Give an example of an event that agrees with the idea of catastrophism. The sudden demise of the dinosaurs, and various other groups, by the impact of a large extraterrestrial body with Earth. The "inheritance of acquired characteristics" proposal was put forward by: Lamarck Malthus' essay led Darwin to which of the following generalizations? All organisms produce more offspring than their environment can support. Catastrophism,meaning the regular occurrence of geological or meteorological disturbances (catastrophes), was Cuvier's attempt to explain the existence of: The fossil record What is the best source for evidence of evolution? The fossil record When, according to Bishop Usher, was the Earth created? 4004 B.C. Which term is synonymous (in humans) with 'Anterior'? Ventral A tattoo on the small of your back would be located ________to your spine. Dorsal What describes a parasagittal plane? any sagital plane except the median The anatomical position is used____ ass a standard reference point for directional terms regardless of the actual position of the body. The elbow is ________to the wrist. proximal Your hip bones are lateral to your bellybutton. True or False? True Your hip bones are both lateral and inferior to your bellybutton. True or False? True Your knee is proximal to your ankle. True or False? True What is a vertical section through the body, dividing it into anterior and posterior regions called? Transverse Your wrist is distal to your fingers. True or False? False The head defines which position in animals? Anterior Your hip bones are inferior to your bellybutton. True or False? True Your wrist is distal to your elbow. True or False? True The term that means "towards the head" in humans is... Superior What is a horizontal section through the body, diving it into dorsal and ventral regions called? Frontal When you rub a cat's back you are touching its ____ surface. Dorsal Your wrist is proximal to your elbow. True or False? False Radial Symmetry is... When you can slice it in the same direction, but anywhere on it, and still have all the same pieces. Ex. a circular flower pot. Who described and named the first verifiable specimen of Megalosaurus? William Bluckland Gastroliths are stones that dinosaurs swallowed to help grind up their food. True or False? True What was Charles Darwin's role in dinosaur fossil collecting? None A bone map is a set of directions TO a specific location containing fossils. True or False? False What is the correct name for 'Brontosaurus'? Apatasaurus What did Hitchock conclude was the source of the Connecticut valley dinosaur tracks?  Large (very large) flightless birds Which museum did Andrew Carnegie found (and fund)? Carnegie museum in Pittsburgh Who coined the terms Saurischia and Ornithischia? Harry Seelel Which legendary creature is probably a misinterpretation of Protoceratops fossils? Griffen Which dinosaur paleontologist tried to become King of Albania through less than normal processes? Nopsca Who are we certain discovered Iguanodon? Gideon Mantell What Chinese legend probably refers to the remains of dinosaurs? Dragon bones Which continent was the LAST one on which dinosaur fossils were found? Antartica Who led the dinosaur expeditions to the Gobi? Roy Chapman Andrews Bone Cabin Quarry is so named because there was a cabin there built from dinosaur bones. True or False? True When did the Dinosaur Renaissance begin? 1970 O.C. Marsh named coprolites (dinosaur feces) after his rival E.D. Cope. True or False? False Which Indian tribe incorporated dinosaur tracks in their religious motifs? Hopi The dinosaur art of Zdenek Burian was heavily influences by the art of... Charles R. Knight The first dinosaur to be described scientifically was___________. Megalosaurus The principle purpose of the central Asiatic Expeditions of the American Museum of Natural History was to _________________.  Search for fossils of Human ancestors The many dinosaur skeletons collected during the great dinosaur rush were primarily studied by _______________________.  Cope and Marsh There have been ____ distinct concepts of the dinosaurs during the 170 or so years that they have been studied scientifically. 3 The most influential dinosaur artist of all time was... Charles R. Knight Two men, _____ and _____, collected more dinosaurs than anyone else in history. Brown, Sternberg The two scientists most closely associated with the "Great Dinosaur Rush" (A.k.a. the Bone Wars) were___ Marsh and cope complete dinosaur skeletons were discovered in North America between ______________________. 1870 and 1900 Iguanodon was so names because its Teeth resembled those of an iguana The first partial skeleton of a dinosaur discovered in North American was Found in ____ New Jersey The two scientists most closely associated with the "Dinosaur Renaissance" were ... Ostrom and Bakker The scientific study of dinosaurs begain in __________ during (the) _______. England, 1820's A family tree or genealogy of taxa A monophyletic group is identified by shared evolutionary novelties "Lamarckian Evolution" is synonymous with "Evolution by natural selection." True or False? False "Darwinian Evolution" is synonymous with "Evolution by natural selection." True or False? True A horizontal slice through a phylogeny Tyrannosaurus rex is part of the following hierarchical classification__________. Vertebrata, Reptillia, Archosauria The Linnean classification proves Darwinian evolution. True or False? False gives preference to the first name proposed. The International Code of Zoological Nomenclature __________. sets standards for naming taxa Evolution by natural selection is ________. Darwinian evolution Natural selection as a mechanism of evolution was proposed by: Darwin AND Structures which are derived from the same body part in a common ancestor but may have difference appearances and functions are called: Homologous structures Structures which are derived from the same body part in a common ancestor but may have different appearances and functions are called: Synapomorphies The Linnean classification scheme is hierarchical. True or false? True In which kind of deposits are dinosaur fossils found? Fluvial tracks, eggs, skin impressions, gastroliths, and coprolites Dinosaurs first appeared during the ____________. Late Triassic Similar dinosaurs suggest the same, Late Jurassic age for rocks located in _____ and _______. Tanzania, United States The Cretaceous period lasted from ___to____? 145-65 mya As a general rule, how long does it take bones to fossilize? 10,000 years. Dinosaurs became extinct at the end of the ________. Cretaceous burial and some form of mineralization. The Jurassic period lasted from _____ to_____. 200-145 mya What type of rock is formed by the cooling of molten magma or lava? Igneous Ichnofossil is synonymous with ___?__ fossil. Trace Geologists recognize three types of rock: igneous, metamorphic, and sedimentary What rock is formed by cementing together of particles eroded from igneous or metamorphic rock? sedimentary allows us to determine the relative age of rocks. Most dinosaur fossils from lacustrine sedimentary rocks _____. are from shoreline or river-delta deposits on the lake margins what is not an ichnofossil? a bone Fluvial refers to _____.  rivers The notion that rocks which contain the same fossils are of the same age is known as the ________. Principle of Biostratigraphic correlation the principle of biostratigraphic correlation states that... Rocks with the same types of fossils are the same age Deposits formed by blowing winds are known as ... Eolian Most dinosaur fossils are found in... Fluvial sedimentary rocks Deposits formed in a lake are called... Lacustrine There are two groups of diapsid reptiles, the ____ and ____ Lepidosaurs, archosaurs An incipient frill is the principal evolutionary novelty of the..... Marginocephalia The known thecodont closest to a suitable ancestor of the dinosaurs is..... Lagosuchus Thyreophoran dinosaurs are united principally by their _______ body armor Distinctive features of ornithischian dinosaurs include... A toothless predentary The supercontinent in the early Mesozoic was _______. Pangea Middle and late cretaceous dinosaur faunas were documented by: hadrosaurids, ceratopsians, and ankylosaurs The largest animal known to have lived in the late triassic seas was an ichthyosaur The late Jurassic has been called the _____. golden age of dinosaurs The following groups of animals first appeared During the late Triassic ________. Turtles and mammals The largest marine predators of the Early and Middle Jurassic seas were huge plesiosaurs The worldwide climate of the Cretaceous can best be described as ______ a greenhouse The Late Triassic world was..... full of theocodonts Flowering plants first appeared during the _____ Early Cretaceous By the Early Jurassic _______ were extinct thecodonts During the Early and Middle Jurassic, parts of Pangea were covered by .... vast deserts The sea that separated Laurasia from Gondwana during the Jurassic was the  Tethys The following continents were part of Gondwana South America, Africa, Antartica The easiest way to identify a dinosaur footprint is to collect its underprint. True or False? False If polished stones are not found associated with dinosaur bones, we cannot confidently term the gastroliths. True or False? True Unlike ornithopod footprints, theropod footprints have _____ impressions and lack _____ impressions. claw, heel The shapes of dinosaur eggs vary considerably. True or False? True Some trackways of ankylosaurs and ceratopsians suggest more erect forelimb postures than do studies of their bones. True or False? True The biggest problem when interpreting coprolites is... identifying the animal that made them Dinosaur feet were about _____ as long as their legs one fifth Gizzard stones, found with fossils, are called gastroliths Dinosaurs became extinct because their egg shells were too thing. True or False? False Known dinosaur coprolites are mostly of ______ predatory dinosaurs Dinosaur fossils are known from all the continents except antartica. True or False? True Dinosaur coprolites are known that are as much as ______ centimeters long. 29 Dinosaur eggs provide important information about _____  the reproductive behavior of dinosaurs The longer the relative stride, the faster the ______ dimensionlessspeed Dinosaur trackway is an obvious example of fossilized behavior. True or False? True Supposed human footprints associated with dinosaur footprints are fakes. True or False? True Dinosaur footprints are given the same Latinized scientific names as are assigned to dinosaur body fossils. True or False? False There are two families of pachycephalosaurs, the ______ and ______ Homalocephalidae, Pachycephalosauridae Evolutionary novelties of the ceratopsians include a _______ all of the above Unlike other ceratopsines, Triceratops had A short frill that lacked fenestrae There were probably ____ species of Triceratops. One Evolutionary novelties of ceratopsids include _____ Very Large skulls Features of the pachycephalosaurid skull and skeleton designed to resist impacts include the >>>>> all of the above The most primitive pachycephalosaurus were the  homalocephalids Pachycephalosaur and ceratopsian evolution took place primarily during the _____ Cretaceous All protoceratopsids were of _____ age Late Cretaceous Ouranosaurus belongs to which family? Iguanodontidae The zenith of hypsilophodontid diversity was during the ... Lare Jurassic and Early Cretaceous The large tusks of Heterodontosaurus were used for _____ defense and display In a skull, what is the name of the bone located at the back of the lower jaw?  Quadrate The Ornithopod clade known as the "Hadrosaurinae" is now known as the ___? Saurolophinae Two subfamilies of hadrosaursids are recognized, the ____ and ____- Hadrosaurines, lambeosaurines A conspicuous characteristic of Heterodontosaurids is their... offset premaxillary tooth row Heterodontosaurids are known only from the ____ Lower Jurassic of Southern Africa Hypsilophodon was a  biped On a skull, the bone that is located at the very front of it is called the _____ Premaxilla characteristic features of iguanodontids include ____ A long, horse-like snout Characteristic features of hadrosaurids include... all of the above The zenith of iguanodontid diversity was during the ____ Early-Middle Cretaceous Maiasaura belongs to which subfamily? Hadrosauridae Which of the following is not a synapomorphy of the ornithopods? Obligate bipedality Saurolophus belongs to which subfamily? Lambeosaurines Which of the following is a synapomorphy of the hadrosauridae? Laterally flared premaxillary bones An unusual feature of Ouranosaurus was its long neural spines was the first dinosaur described by a scientists Unlike Herodontosaurus, the skull of Hypsilophodon was ______ Kinetic The Ornithopod clade known as the "Lambeosaurinae" is now known as the ... Lambeosaurinae pterosaurs were the ancestors of birds. True or False? False The only feature of Archeaopteryxnot possessed by a theropod was its _____ Feathers Archaeopteryxhad no teeth. True or False? False Lacked horns at their postierior corners Ankylosauridshad The plates of stegosaurus primarily functioned as  B or C The most primitive known stegosaur is scutellosaurus The Cretaceous decline of the stegosaurs may have been due to _______ A and B The key evolutionary novelty of the thyreophorans is their Armor plates Characteristic features of stegosaurids include _____ Low skulls with long snouts Stegosaurs and ankylosaurs are united in a group called  Thyreophora The evolutionary split between nodosaurids and ankylosaurids took place by the ... Cretaceous The many distinctive evolutionary novelties of the Ankylosauria include _____ All of the above The key evolutionary novelty of stegosaurs was their Bony plates and spines The oldest known bird is Archaeopteryx Birds are the bost dirverse group of extant vertebrates except for the bony fishes. True or False? True The hallmarks of birds include.... Feathers Theropod-like features of Archeaopteryx include Three fully developed digits on each hand A ratite is a(n) Air passes though small openings in bird long bones; these bones are this______ Pneumatic Protoavis is the oldest bird. True or False? False Many bones of the avian skeleton are fused to form rigid structures. True or False? True Birds belong to a single class of vertebrates, the _____ Aves During the Early Cretaceous, birds were already diverse. True or False? True The following are typical modifications of the forelimb of birds: Keeled sternum, fused carpals Dinosaurs were very bird-like, but we continue to classify them with... reptiles Birds are descended from tetanuran theropods. True or False? True Archaeopteryxcan reasonably be called a feathered dinosaur. True or False? True Some paleontologists classify Archaeopteryx as a _____  all of the above Fossils of the Archaeopteryx come from only one place, the _____ Upper Jurassic of Germany The cretaceous decline of the stegosaurs may have been due to _____ a and b Lacked horns and their posterior corners Stegosaurs ate ____ Ankylosauria is composed of two families _____ and _______ Nodosaurisae and Ankylosauridae Stegosaurs reached the zenith of their diversity during the ______ Late Jurassic The key evolutionary novelty of stegosaurs was their  Bony plates and spines The plates of Stegosaurus primarily functioned as  b or c The key evolutionary novelty of the thyreophorans is their  Armor plates The hind limbs of stegosaurus were Long and Pillar-like The evolutionary split between nodosaurids and ankylosaurids took place by the _____ Cretaceous Stegosaurs and ankylosaurs are united in a group called _____ Thyreophora Ankylosauridsare known only from the Cretaceous of, _____ North America, Europe, and Asia Characteristic features of stegosaurids include.... low skulls with long snouts Ankylosauridshad... The folded nasal passages of ankylosaurids may have functioned as  resonating chambers The many distinctive evolutionary novelties of the Ankylosauria include... all of the above The extremely broad sacrum of Scelidosaurus suggests affinities with the _____ Ankylosaurs The defensive strategy of ankylosaurs was based on _______ impervious armour The most primitive known stegosaur is huayangosaurus Evolutionary novelties that distinguish theropods from other dinosaurs include... all of the above The best known and only trutly abundant coelursaurs are the .... ornithomimosaurids Tyrannosaurid fossils are of ___ age late Cretaceous All dinosaurs cared for their young. True or false? False Other than some ____ no compelling argument can be presented that any dinosaur was aquatic hadrosaurids The color of dinosaurs is totllay a matter of conjecture. True or False? True The poorly formed limb joints of hatching Maiasura suggest they were _____ altricial It is easy to determine exactly what kinds of plants or animals a given dinosaur ate. True or False? False One of the principal reasons most animals, including dinosaurs locomote is to ____ obtain food Boners of juvenile Rioarribasaurus inside the abdomens of adult Rioarribasaurus indicate ____ Cannibalism The posture and overall body shape of a dinosaur is determined by analyzing its _____ skeleton Dinosaurs might have had _____ chambered hearts, like living birds and crocodiles four Among vertebrates there is a striking correlation between upright limb posture and ______ endothermy Because of the surface area to volume relationship, a larger dinosaur had ____ surface area than a smaller dinosaur relatively less Ectotherms receive most, or all, of their body heat from tan external source, usually directly from the sun. True or False? True Complex social behaviors are characteristic of many endotherms and uncommon amoung ectotherms. True or False? True

Gastrolith

Which animal has been hunted almost to extinction because of its horn?

Biological issues in Jurassic Park | Disasterpedia Wiki | Fandom powered by Wikia Biological issues in Jurassic Park 372pages on Add Image &nbsp Jurassic Park, a book by Michael Crichton , with a film version directed by Steven Spielberg , revolves around the resurrection of dinosaurs via genetic engineering . Scientists and enthusiasts have brought up a number of issues with facts and feasibility. Some of the speculative or inaccurate features attributed to the dinosaurs of Jurassic Park have become embedded in popular culture, most popular among them being the idea of Tyrannosaurus only seeing motion; giant, feather-less, intelligent velociraptors , and dwarf, frilled, poison-spitting Dilophosaurus . In general, the novel is more accurate than the film, with Spielberg adding some features to the dinosaurs (like the frill on the dilophosaurs). Contents File:Vraptor-scale.png The raptors in the novel, following through to the film raptors, were larger than the species going by the name because during the writing of the novel, a previously discovered dinosaur named Deinonychus (closely related to Velociraptor , but larger) was interpreted as a Velociraptor species by some scientists, notably Gregory S. Paul . [1] In the novel, Deinonychus is mentioned, but the character Alan Grant then says that scientists have reclassified it as a species of Velociraptor. Crichton wrote his novel based on the idea of a human sized raptor, but after the publication, when the film was already in production, the idea of Deinonychus being a Velociraptor species was dropped by the scientific community. The film makers had the size of the film's Velociraptor increased for dramatic reasons, and changed the shape of the snout. [2] However, during filming, paleontologists came across a larger dromaeosaurid species named Utahraptor and the larger raptors remained, even though Utahraptor was substantially larger (21 feet long) than the film's raptors. At the start of the film, a Velociraptor skeleton is uncovered in Montana ; no examples of the dinosaur have been uncovered in the United States (although both Deinonychus and Utahraptor are American dinosaurs). The fossil skeleton is similarly inaccurately large. The high intelligence of the film's velociraptors are considered somewhat unlikely by scientists, given the relative size of their brains and comparisons with modern animals. [3] File:Velociraptor dinoguy2.jpg It is now known that Velociraptor had feathers . [4] Neither the film nor the novel dinosaurs had feathers; however, both were created before the discovery of feathered dinosaurs closely related to Velociraptor (e.g. Microraptor ). [5] [6] In Jurassic Park III , the raptors were remodelled and small feathers on the males ' heads were included, while still looking similar to the original design. As with other bipedal dinosaurs in the films, the hands of Velociraptor are depicted with the palms able to rotate, but this would have been anatomically impossible for the real animals, as their forearm bones ( ulna and radius ) could not rotate in this way. Their palms should have been relatively fixed facing each other, like a person about to clap . [6] Dilophosaurus File:Dilophosaurus scale.png The film's Dilophosaurus stands about 1.2  meters (4 ft) tall, [7] while its real-life counterparts measured on the order of 6 meters (20 ft) long and 1.4 meters (4.5 ft) tall at the hips. [8] According to a " Making-of " book, this was a deliberate deviation from accuracy for stylistic purposes, and to differentiate it from the velociraptors. [7] It also has a frill like the Australian frill-necked lizard , which is not considered accurate by paleontologists. The novel's version is full-sized and lacks the frill. Both depictions of the dinosaur eject a potent, blinding venom in both their bite and their spit, like a spitting cobra , and use it to hunt ; the novel acknowledges the fact that this is not suggested by fossil evidence. [9] Tyrannosaurus Edit The film theorizes that the Tyrannosaurus rex would be unable to see someone if he stayed still; however, evidence has shown T. rex to have had high visual acuity and binocular vision . [10] Some argue that it would still be able to smell them regardless. [11] In the novel, it is mentioned that the reason the dinosaurs can not see someone standing still, is due to the frog DNA in their genome, and it is shown that other dinosaurs, such as the island's Maiasaura, have this problem as well. This is not mentioned in the film, and instead it is shown as if the inability to see without movement was an actual trait of Tyrannosaurus. In the sequel novel, The Lost World , it is suggested that the Tyrannosaurus can in fact see inanimate objects, and was actually not hungry, but merely "playing" in the first encounter. A character who specifically attempted this technique dies when the T. rex sees him there and kills him; the character Ian Malcolm mentions that he was listening to "the wrong scientists." [12] [13] Tyrannosaurus is also shown as being able to keep (sprinting) pace with a jeep traveling at considerable speed; however, it is debated within the palaeontological community whether a T. rex could even achieve this speed in real life, much less maintain it for as long a period of time as the film depicts. [14] Anatomically, its short forelimbs would have been unable to cushion an impact if it were to fall; meaning that accidents at such speeds could have been fatal. Also, biomechanical studies by Dr John Hutchinson of the Royal Veterinary College have shown that in order to run at this speed in a crouched position, Tyrannosaurus would have needed over 43% of its muscle mass in each leg. That would mean 86% of its muscle mass would be in its legs, leaving little room for anything else in its body: a physical impossibility. Dr Hutchinson’s work also suggests that an upper speed limit for Tyrannosaurus would, actually, only fall in the 10–25 mph range. [15] Animators at Industrial Light & Magic were forced to use optical illusions in order to make the computer-generated Tyrannosaurus appear to convincingly keep pace with the vehicle. [16] Brachiosaurus Edit The Brachiosaurus in the film is shown to be chewing its food with a side to side motion of its lower jaw. In reality, it could not feed like this. Brachiosaurid skulls and jaws were limited to up and down motions, and their teeth were specialized for shearing and cropping plant material. Other sauropods , such as diplodocoids , could move their jaws backward and forward, but were probably using this motion to strip branches, not to chew plants. [17] Instead of processing food in the mouth, sauropods probably relied on taking in as much food as possible and processing it farther down the digestive tract, either through gastroliths (rocks swallowed and used for grinding in a gizzard -like organ; note however that this hypothesis, while common in the popular literature, is now considered unlikely in sauropods), [18] or simply by digestion through fermentation by microorganisms. [19] One of the most well known scenes of the movie shows a brachiosaur rearing into a bipedal stance. However, a biomechanical analysis of sauropod rearing abilities shows that Brachiosaurus is probably the sauropod least able to rear. [20] It has a center of mass placed further forward than any other sauropod , [21] which means that a bipedal or tripodal pose would be highly unstable. Pteranodon File:Pteranodon cat.jpg Like the Cearadactylus in the novel, the Pteranodon in Jurassic Park III is interpreted as aggressive and able to pick a teenager up with its feet (a similar scene was planned for the climax of The Lost World: Jurassic Park , but omitted after palaeontological advisers on the production declared that this would not have been possible). Both pterosaur genera were thought to have eaten fish, [22] and were incapable of grasping with their feet. However, in the novelization it states that they were able to carry things with their feet due to them being genetically engineered. Also, although the name Pteranodon means 'winged without teeth' or 'winged toothless', the Pteranodon in Jurassic Park 3 have small sharp teeth in their bills. Procompsognathus and Compsognathus Edit The Procompsognathus are given several attributes in the novels that cannot be determined from the fossil evidence to date. They are presented as living and hunting in large groups; as scavengers and coprophagists (eaters of feces ), useful in keeping the park clean of sauropod excrement; and as secreting a venom described as similar to that of a cobra , although more primitive. In the films, they are dropped in favour of Compsognathus . In reality, Procompsognathus is known from a single partial skeleton from the Late Triassic of Germany , with a partial skull that may belong to it or, more likely, an early relative of modern crocodilians . [23] [24] Because only one individual is known, there is no direct evidence that it lived in groups; however, related animals such as Coelophysis and Megapnosaurus have been found in groups of numerous individuals, such as at Ghost Ranch . [24] As there are no uncontroversial remains of the head of Procomposognathus, its diet cannot be inferred from the form of its teeth and jaws; other coelophysoids are seen as carnivores with skull adaptations that may have been advantageous when handling small prey. [24] There is no evidence that the bite of Procompsognathus was venomous. A venomous bite has been proposed for a possible theropod from the Late Cretaceous of Baja California , known from a single tooth with grooving similar to that found on the teeth of venomous snakes and lizards. [25] A venomous bite has also been proposed for the Lower Cretaceous Chinese dromaeosaurid Sinornithosaurus , based on its long grooved teeth similar to those of rear-fanged snakes , as well as a possible venom-gland cavity in the bone of the upper jaw. [26] [27] Spinosaurus Edit The Spinosaurus in Jurassic Park III appeared to be larger and more heavily built than its real-world counterpart. Also, its teeth were very straight, conical and crocodilian in reality, but they are hooked and serrated in the film. Spinosaurus also had only one crest on its head, not two. Biotechnological background File:Mosquito in amber.jpg The popularity of the novel and movie have sparked actual debate in the laymen and scientific community, as to the plausibility of actually recreating dinosaurs. In the novel/movie the dinosaur DNA is extracted from fossilized mosquitoes, and this small amount is then amplified by polymerase chain reaction (PCR). This has been done before, for example with a Cretaceous weevil in Cano et al. (1993) (no dinosaur DNA was found). There are some problems with this approach: The DNA featured in the movie comes from a Dominican amber mine, though this mine is never stated to be the sole source. The novel indicates sources are global as Hammond's widespread purchasing and stockpiling of amber comes under scrutiny. Dominican amber is 10 million years to 30 million years old, [28] whereas dinosaurs died out 65 million years ago. None of the dinosaurs featured in the movie are known to have existed in the Dominican Republic 65 million years ago (though, again, whether that mine is the only source for DNA is unknown). The mosquito had to have had just one species of dinosaur as its food source to avoid a mix-up. Since some species of mosquito have a female lifespan of only a few days and tend to lay eggs following each feeding, this is semi-plausible, though in that case dozens of mosquitoes of different species would have to be found in order to recreate as many kinds of dinosaurs. The scene featuring a close-up of the mosquito clearly shows fuzzy antennae, meaning the particular insect is male. Only female mosquitoes, however, suck blood. It is unknown which dinosaur the sample contains. It would be impossible to tell which species it is, because the DNA sequences would fit somewhere between that of birds and crocodiles . The book does address this, stating that they "just grow it and find out", to mathematician and chaos theorist Ian Malcolm 's annoyance. The dinosaur DNA has to be correct (it has to contain every chromosome ) and should contain no sequence gaps. The book and movie did address this issue, however, and had the scientists use frog DNA (and also bird and lizard DNA in the novel) to compensate for the gaps in the dinosaur DNA. The DNA is mixed with mosquito, bacterial, and viral DNA. Although PCR is very specific, it is sensitive to contamination, and if the wrong primers are used, it will also amplify the other DNA. Because DNA is broken down by nucleases in the mosquito gut, the mosquito would have to be preserved immediately after feeding; this would be problematic for the park's scientists, although it would explain the lack of mass contamination in the individual samples. The processes of CpG methylation and cytosine deaminization must also be considered. A common regulatory device in eukaryotic DNA is the process of CpG methylation, where cytosine immediately preceding a guanine on the same strand is methylated. This acts as a molecular flag to control gene expression. Over time cytosine deamination can occur, in which a cytosine amine group is hydrolysed (replaced with a carbonyl oxygen). An unmethylated cytosine will read as uracil in any technique that relies on Watson-Crick base pairing. If the cytosine has been methylated then the product of deamination will be thymine, which again will be read as thymine. This issue can be addressed in a number of ways. If the DNA sample taken contains more than one copy of the DNA, a mixed signal of thymine and cytosine will suggest the occurrence of cytosine deamination. If the entire sample has suffered cytosine deamination at that point in the sequence, CpG tend to be found in "islands" rich in CpG, so TpG-rich islands or TpG/CpG rich islands would suggest cytosine deamination. Furthermore, in the fossilization process, molecules are altered. Nevertheless, amber is the best preservative, because organic material is preserved. But DNA cannot survive completely without gaps for tens or hundreds of millions of years. The novel attempts to address this problem by mentioning that Hammond and INGEN have purchased virtually the world's entire stock of amber, in the quest for the maximum number of possible samples of blood from ancient mosquitoes. However (see below) the admixture of different strains of dinosaur genetic material makes the acquisition of viable genetic material haphazard at best, coupled with the CpG Methylation (see above). That said, the use of multiple Cray X-MP supercomputers whose sole task is pattern recognition is doubtless a shrewd guess as to the size of the task and the scale of resources needed to perform the feat. Tens of thousands of DNA base pairs were recently sequenced from 40,000-year-old skeletal remains of cave bears without using PCR, establishing that, in principle, large-scale genomic sequencing of fossilized remains is possible. Template:Citation needed . Of course, the remains used in this study are orders of magnitude younger than anything from the dinosaur era, and the technique might not extend to those creatures. In the book the gaps in the DNA are filled by hybridizing the DNA with either bird, lizard, or frog DNA. In the movie, only frog DNA is used. This is extremely difficult, as one would need to know which dinosaur genes are homologous with frog genes. The use of frog genes was a plot device , to allow some females to change sex and breed (although natural sex change is also possible in other vertebrates , such as fish). The dinosaurs were genetically altered so they could not produce lysine , forcing them to depend on lysine supplements provided by the park's veterinary staff. Most vertebrates cannot produce lysine by default, which makes it an essential amino acid for them. The movie states that all dinosaurs are female because all vertebrate embryos are inherently female, requiring an extra hormone at the right phase to make them male. This is not technically true. Vertebrate embryos are undifferentiated, possessing organs that can grow into either male or female reproductive systems. In mammals, at a certain developmental stage the Y chromosome triggers a flood of testosterone , causing the fetus to develop into a male. If, for some reason this doesn't happen, the fetus will develop as an XY female (See Swyer syndrome ). Birds and reptiles (and presumably, dinosaurs) don't use Y chromosomes in this way. In fact, they seem to use an opposite system with females possessing a W chromosome and a Z chromosome and males possessing two Z chromosomes. In the scenario presented in Jurassic Park, it seems likely that all the dinosaurs in the park would have been functional males or sterile males possessing an extra chromosome (See Hermaphrodite ). The next step would be bringing the DNA strands to expression. For that, one would need to inject the dinosaur DNA into the nucleus of a fertilized egg cell of a close relative of dinosaurs (birds or crocodiles, not frogs). This technique is based on reproductive cloning , which was used to clone Dolly . In the movie, ostrich and emu eggs are used for this purpose. However, the development of an embryo is regulated by hormones in the egg/uterus and the environment. These (bird or crocodilian) hormones need to have the same effect as their original dinosaurian counterparts. For that, they have to be able to recognize particular pieces of dinosaur DNA, a currently impossible task. New research in plastics, however, has allowed for the creation of synthetic eggs such as those that were used in the book. Template:Citation needed In the book, Henry Wu claims that egg yolk is nothing but a growth medium that can be created in a laboratory. However, if it were this simple, an embryo could just be put into such a medium and left to grow (a scene in the third movie seems to show that some embryos were placed in tanks and that the scientists achieved some success because the embryos did grow big enough to be visible Template:Citation needed . Extra hormones are needed from the original parent specimen, however, or constructed precisely from using the genome in order for the embryo to flourish.

i don't know

Which chemical, commonly used to increase crop yield, sometimes contaminates drinking water?

Potential Carcinogens in Your Drinking Water and How to Test for Contamination Bringing Drinking Water & Insight To The World Cancer Awareness: “Top Ten” Potential Risks in Your Drinking Water (Part 1 of 2) by wfnblog on October 20, 2011 Many of us are increasingly unsettled about the potential harm of a growing number of contaminants in tap water, especially those which adversely impact human health. Since the 1970s, sampling for water pollutants has markedly increased. Now hundreds of manufactured chemicals have been found in the groundwater and various other drinking water sources. Chemical contamination of drinking water can be traced to several different causes, including wrongful disposal of household cleaners, leaking underground storage tanks, seepage from landfills, discharge from factories and increased pesticide & fertilizer use over the past fifty years. As troubling as the discovery of contaminated drinking water is, it’s a more hopeful sign that in recent decades, laboratories have become much more finely skilled in detecting a long list of chemicals. More importantly, our scientific knowledge of the health risks linked to drinking water contaminants has also improved. As a result, various home water treatment options are now widely available for reducing exposure to chemicals in tap water. Some contaminants are known to cause cancer in the human population.  Others are suspected culprits. These contaminants are commonly referred to as carcinogens. When the Environmental Protection Agency (EPA) establishes primary drinking water standards for carcinogens, the EPA acknowledges that no concentration in drinking water is safe, but it also must decide what level of risk is tolerable for the purpose of regulation. For many carcinogens, the concentration in drinking water causing no more than one cancer per million is typically in the range of a few parts per billion.  Although more research continues to be done on an ongoing basis, here are our current “top ten” contaminants of possible concern: Synthetic Organic Chemicals: Pesticides, Fertilizers, THMs, VOCs, Solvents 1. Pesticides are manufactured by humans from carbon, chlorine, hydrogen, nitrogen and other elements for a variety of purposes. The health effects of pesticides depend on their chemical characteristics. The use of pesticides, which include insecticides, herbicides and fungicides, is widespread in commercial farming and residential landscaping. Pesticides enter the groundwater during accidental spills, improper application, illegal dumping, manufacturing discharge or excessive rainfall after normal application. These agricultural chemicals can contain substances that disrupt the endocrine system. Some of these chemicals break down very slowly,  so they persist in the environment—even in non-agricultural areas. 2. Fertilizers are another group of chemicals commonly used in agriculture to increase crop yield. Fertilizer by-products, formed as a result of natural chemical processes, however, can be potentially carcinogenic. These agricultural chemicals are one of the major sources of water pollution. For instance, the nitrogen in fertilizers gets converted into nitrate that seeps into groundwater. When ingested, nitrates form nitrosamines which have been found to cause tumor growths in animal studies. 3. Water Disinfection By-Products (THMs) are another issue. Although disinfection of the drinking water supply with chemicals like chlorine has dramatically reduced outbreaks of waterborne illnesses and deaths, research has suggested that long-term exposure to disinfection by-products may elevate cancer risk. Hundreds of disinfection by-products have been identified, but only a few are monitored. Even fewer have been tested for carcinogenicity. One common category of by-products are trihalomethanes, which form when chlorine and/or bromine combine with organic material in the water, such as decomposing leaves or animal waste. Some examples of THMs that may exist in drinking water are chloroform and bromoform. 4. Volatile Organic Compounds (VOCs) are chemicals that tend to evaporate quickly at normal room temperature. When dissolved in water that is stirred or heated, VOCs readily move into the surrounding air. VOCs are commonly found in agricultural and industrial areas where runoff, leaks, spills and dumping may contaminate groundwater. Some VOCs, such as benzene and carbon tetrachloride, are known to cause certain forms of cancer, including leukemia. 5. Dry Cleaning Solvents, such as trichloroethylene and perchloroethylene, are solvents commonly used in the professional laundry cleaning industry. Ever since the invention of modern dry cleaning techniques, cleaners have nearly always used some form of petroleum solvent or synthetic petroleum distillate. Many cleaners today have put a marketing spin on this calling it “organic”–which is essentially factual since petroleum is an organic substance. It implies, however, that these solvents are “green” or environmentally friendly, which they are certainly not. They are toxic. As known carcinogens, they must be handled with extreme caution. According to the April 2010 report of the President’s Cancer Panel , people living in the area of Camp Lejeune, North Carolina, had been consuming water for thirty years contaminated by these two chemicals at levels more than 40 times higher than the current permitted limit. High rates of cancers, birth defects and illnesses have been attributed to this massive water pollution. Inorganic Chemicals: Heavy Metals, Arsenic and Asbestos, Perchlorate Unlike organic chemicals which contain carbon, inorganic chemicals may or may not contain carbon. Inorganic chemicals can get into the drinking water supply when groundwater passes through contaminated earth.  They can also contaminate water as a direct result of human activities:  mining, agricultural practices, industrial dumping, oil or gas drilling, improper disposal of household batteries, corrosion of municipal water systems, and other sources. Long-term consumption of water containing high levels of certain inorganic chemicals is known to cause chronic health effects, including some forms of cancer. 6. Heavy metals such as chromium comprise one category of inorganic chemicals. Iron, copper, and zinc are common heavy metals found in drinking water, but they are not considered carcinogens. Heavy metals which are known or suspected to cause cancer include nickel, lead, chromium, cadmium and beryllium. The EPA has established drinking water standards for each of these inorganic contaminants. Hexavalent chromium is an essential element in steel production, wood preserving, leather tanning, dye manufacturing and more. Long-term exposure to chromium compounds has also been known to cause nasal, nasopharyngeal and lung cancers. Improper disposal of the chemical by industrial plants has exposed the general public to chromium through drinking water. In fact, according to a 2010 study commissioned by the Environmental Working Group, water supplies in 31 out of 35 American cities were polluted with hexavalent chromium.  Here are the “top ten” cities at risk for exposure. 7. Arsenic, a highly toxic substance, naturally occurs in drinking water.  Inorganic arsenic typically exists in a soluble state (easily dissolved in water) so it will often enter groundwater from the use of certain insecticides and defoliants. Activities such as mining, ore processing and fossil fuel burning also increase arsenic levels in water. The current drinking water standard for arsenic is 50 mcg/L. The EPA is considering tightening this drinking water standard further, however, based on studies that suggest arsenic may cause cancer at even lower levels. Inorganic arsenic in drinking water has been linked to many types of cancer, including: bladder, kidney, prostate, lung and skin cancer. 8. Asbestos, under natural conditions, is a mineral found in certain rock formations. When  asbestos is detected in the drinking water supply, it can be traced to various manufactured sources such as building and fireproofing materials. Asbestos poses a greater risk to humans who breathe it in the air. The current drinking water standard for asbestos is 7 million fibers per liter. 9. Perchlorate, a rocket fuel component and by-product of missile testing, has permeated into drinking water systems from numerous industrial sites. This pollutant is now so widespread that it has been detected in the urine of people throughout all parts of the US. Long-term exposure to perchlorate has been shown to induce thyroid cancer in rodents in the laboratory, but its carcinogenic effects on the human population is still unclear. Radioactive Chemicals: Radon and Radium 10. Radon is a colorless, odorless and tasteless gas, known to cause cancer when inhaled or consumed over an extended period of time. Radon is produced by the natural radioactive decay of radium in the ground. Some rocks, such as sandstone, limestone and granite, contain high concentrations of radium–which in turn produce increased levels of radon. Groundwater found in these rock formations may contain elevated amounts of radon. Radon moves easily from water to air, which means that waterborne radon contributes to airborne radon. In general, airborne radon poses a greater health risk than waterborne radon. The EPA, however, reports that the general cancer risk associated with waterborne radon is higher than any other drinking water contaminant. Scientists estimate that the lifetime risk of developing cancer from water containing high levels of radon is approximately one in ten thousand.   If you suspect that your drinking water is unsafe, one of the first steps to consider is to seek additional information about your local water supply. Contact your municipal water supplier for a copy of the most recent test results for your area, or have your private water supply tested for the specific contaminants of concern. If a water quality problem is detected, you may choose from a range of treatment options. We will discuss different water filters for reducing the risk of potential carcinogens in our next article.

Nitrate

When you recycle a drink can, which metal is it you are recovering?

Chapter 3: Fertilizers as water pollutants Organic fertilizers "Eutrophication" is the enrichment of surface waters with plant nutrients. While eutrophication occurs naturally, it is normally associated with anthropogenic sources of nutrients. The "trophic status" of lakes is the central concept in lake management. It describes the relationship between nutrient status of a lake and the growth of organic matter in the lake. Eutrophication is the process of change from one trophic state to a higher trophic state by the addition of nutrient. Agriculture is a major factor in eutrophication of surface waters. The most complete global study of eutrophication was the Organization for Economic Cooperation and Development (OECD) Cooperative Programme on Eutrophication carried out in the 1970s in eighteen countries (Vollenweider et al., 1980). The sequence of trophic state, from oligotrophic (nutrient poor) to hypertrophic (= hypereutrophic [nutrient rich]) is shown in Table 12. Although both nitrogen and phosphorus contribute to eutrophication, classification of trophic status usually focuses on that nutrient which is limiting. In the majority of cases, phosphorus is the limiting nutrient. While the effects of eutrophication such as algal blooms are readily visible, the process of eutrophication is complex and its measurement difficult. This is not the place for a major discussion on the science of eutrophication, however the factors noted in Table 13 indicate the types of variables that must be taken into account. Because of the complex interaction amongst the many variables that play a part in eutrophication, Janus and Vollenweider (1981) concluded that it is impossible to develop strict boundaries between trophic classes. They calculated, for example, the probability (as %) of classifying a lake with total phosphorus and chlorophyll-a concentrations of 10 and 2.5 mg/m3 respectively, as: Phosphorus The symptoms and impacts of eutrophication are: · Increase in production and biomass of phytoplankton, attached algae, and macrophytes. · Shift in habitat characteristics due to change in assemblage of aquatic plants. · Replacement of desirable fish (e.g. salmonids in western countries) by less desirable species. · Production of toxins by certain algae. · Increasing operating expenses of public water supplies, including taste and odour problems, especially during periods of algal blooms. · Deoxygenation of water, especially after collapse of algal blooms, usually resulting in fish kills. · Infilling and clogging of irrigation canals with aquatic weeds (water hyacinth is a problem of introduction, not necessarily of eutrophication). · Loss of recreational use of water due to slime, weed infestation, and noxious odour from decaying algae. · Impediments to navigation due to dense weed growth. · Economic loss due to change in fish species, fish kills, etc. TABLE 12: Relationship between trophic levels and lake characteristics (Adapted from Janus and Vollenweider, 1981) Trophic status Major algal groups and dominant species Bottom fauna standing crop Epilimnetic D P, D N, D Si (D is difference between winter and summer concentrations) Particulate organic carbon and N Hypolimnetic O2 and D O2 Daily primary production rates Annual primary production Secchi disc visibility Role of agriculture in eutrophication In their summary of water quality impacts of fertilizers, FAO/ECE (1991) cited the following problems: · Fertilization of surface waters (eutrophication) results in, for example, explosive growth of algae which causes disruptive changes to the biological equilibrium [including fish kills]. This is true both for inland waters (ditches, river, lakes) and coastal waters. · Groundwater is being polluted mainly by nitrates. In all countries groundwater is an important source of drinking water. In several areas the groundwater is polluted to an extent that it is no longer fit to be used as drinking water according to present standards. While these problems were primarily attributed to mineral fertilizers by FAO/ECE (1991), in some areas the problem is particularly associated with extensive and intensive application of organic fertilizers (manure). The precise role of agriculture in eutrophication of surface water and contamination of groundwater is difficult to quantify. Where it is warranted, the use of environmental isotopes can aid in the diagnosis of pollutant pathways to and within groundwater (IAEA, pers. comm. 1996). RIVM (1992), citing Isermann (1990), calculated that European agriculture is responsible for 60% of the total riverine flux of nitrogen to the North Sea, and 25% of the total phosphorus loading. Agriculture also makes a substantial contribution to the total atmospheric nitrogen loading to the North and the Baltic Seas. This amounts to 65% and 55% respectively. Czechoslovakia reported that agriculture contributes 48% of the pollution of surface water; Norway and Finland reported locally significant eutrophication of surface waters arising from agriculture; high levels of usage of N and P are considered to be responsible for proliferation of algae in the Adriatic; similar observations are made in Danish coastal waters; substantial contamination of groundwater by nitrate in the Netherlands was also reported (FAO/ECE, 1991). Appelgren (FAO, 1994b) reported that 50% of shallow groundwater wells that supply more than one million rural residents in Lithuania are unfit for human consumption because of a wide range of pollutants which include pesticides and nitrogen species. In the 1960s Lake Erie (one of the North American Great Lakes) was declared "dead" by the press due to the high levels of nutrients accompanied by excessive growth of algae, fish kills, and anaerobic bottom sediments. Although the ECE (1992) regarded livestock wastes as a point source and excluded it from calculations of the contribution of agriculture to eutrophication in Europe, their statistics indicated that livestock wastes accounted "on average" for 30% of the total phosphorus load to European inland waters, with the rest of agriculture accounting for a further 17%. The situation for nitrogen, as for phosphorus, was quite variable from country to country. Danish statistics indicated that manure contributes at least 50% of the leaching of inorganic N (Joly, 1993). Nitrogen from agricultural non-point sources in the Netherlands amounted to 71% of the total N load generated from within the Netherlands (ECE, 1992). A study by Ryding (1986) in Sweden demonstrated how lakes which were unaffected by industrial or municipal point sources, underwent long-term change in nutrient status as a result of agricultural activities in the watershed. Over the period 1973-1981 the nutrient status of Lake Oren increased from 780 to 1000 mg/m3 for Total-N, and from 10 to 45 mg/m3 for Total-P. Lake transparency declined from 6.2 to 2.6 m and suffered periodic (heavy) algal blooms. As noted in Chapter 1, the US-EPA regards agriculture as the leading source of impairment of that nation's rivers and lakes with nutrients ranking second only to siltation as the pollutant most affecting rivers and lakes. The values cited in Tables 14 and 15 indicate the wide range of nutrient losses that are measured at the plot, field and sub-basin scales. Heavily fertilized crops such as maize tend to have large losses relative to non-intensive uses such as pasture. Agricultural uses associated with poor land management practices that lead to erosion also produce significant nutrient losses. Wastes, manures and sludges, through biological concentration processes, can supply soils with 100 times more hazardous products than fertilizers for the equivalent plant nutrient content (Joly, 1993). This is considered a major environmental (and water quality) problem in periurban areas of many developing countries. Numerous authors report that a high degree of variability at individual sites is expected as a consequence of changes in hydrological regime from year to year. The implication is that estimation techniques using "typical" values of nutrient yield can expect to have a high degree of uncertainty and could be very much in error if estimated from data collected over a single year. TABLE 14: Selected values for nutrient losses Location +27 Note: Values of +/- 15% are likely within detection limits of the methods used. The huge increases in fertilizer use worldwide over the past several decades are well documented. Figure 9 illustrates the historical trends and predicted future needs of fertilizer use. However, fertilizer use (either mineral or organic) is not, of itself, the primary factor in downstream water quality. More important are the land management practices that are used in crop production. FIGURE 9: Fertilizer use development and crop yield evolution in Asian, European and Latin American countries and the United States (Source: Joly, 1993) There is a danger, however, in assuming that all waters have natural levels that are low in nutrients. In some areas, such as lakes located in areas of rich agricultural soils, waters have historically been highly enriched by nutrients associated with natural erosion of fertile soils. In the prairie lakes of Canada, for example, early settlers reported that the lakes were green with algae. In other parts of the world, as in Asia, ancient civilizations so profoundly impacted water quality that there are no longer "natural" levels of nutrients. In such situations the existence of eutrophication, while undeniable, must be measured against arbitrary standards that reflect water quality criteria established on the basis of societal needs for beneficial use of the water. Organic fertilizers The importance and, in some cases, the major problems associated with organic fertilizers, deserve special mention. Manure produced by cattle, pigs and poultry are used as organic fertilizer the world over. To this is added human excreta, especially in some Asian countries where animal and human excreta are traditionally used in fish culture as well as on soils. However, intensive livestock production has produced major problems of environmental degradation, a phenomenon which has been the subject of European and North American legislation and control. The problem is particularly acute in areas of intensive livestock production, such as in the Eastern and Southern parts of the Netherlands where the production of manure greatly exceeds the capacity of the land to assimilate these wastes. In addition to problems associated with excessive application of manure on the land, is the problem of direct runoff from intensive cattle, pig and poultry farms. Although this is controlled in many western countries, it constitutes a serious problem for water quality in much of the rest of the world. For example, Appelgren (FAO, 1994b) reports that discharge of pig wastes from intensive pig raising in Lithuania is a major source of surface water pollution in that country. The FAO/ECE reports similar problems in the Po River of Italy. The Canadian Department of Agriculture calculated in 1978, on the basis of detailed study of several feedlot operations, that cattle feedlots and manure storage facilities contributed 0.5-13% of the total loading of total phosphorus at that time to the Canadian portion of the Lower (agricultural portion) Great Lakes (Coote and Hore, 1978). To the typical pathways of degradation, that of surface runoff and infiltration into the groundwater, is added the volatilization of ammonia which adds to acidification of land and water. In a review of environmental impacts caused by animal husbandry in Europe, the FAO/ECE (1991) reported the following major categories of impacts: · Fertilization of surface waters, both as a result of direct discharges of manure and as a consequence of nitrate, phosphate and potassium being leached from the soil. · Contamination of the groundwater as a result of leaching, especially by nitrate. Phosphates are less readily leached out, but in areas where the soil is saturated with phosphate this substance is found in the groundwater more and more often. · Surface waters and the groundwater are being contaminated by heavy metals. High concentrations of these substances pose a threat to the health of man and animals. To a certain extent these heavy metals accumulate in the soil, from which they are taken up by crops. For example, pig manure contains significant quantities of copper. · Acidification as a result of ammonia emission (volatilization) from livestock accommodation, manure storage facilities, and manure being spread on the land. Ammonia constitutes a major contribution to the acidification of the environment, especially in areas with considerable intensive livestock farming. Environmental chemistry The key hydrological processes that link rainfall, runoff and leaching, and which give rise to erosion and transport of chemically enriched soil particles, are important components of the environmental chemistry, transport and fate of fertilizer products. These hydrological processes are described in Chapter 2 and are not repeated here. The environmental dynamics of nitrogen and phosphorus are well known although the detailed transformations of nitrogen that occur in soil and water are difficult to study and document. The nitrogen cycle is depicted in Figure 10. Nitrogen is comprised of the forms: soluble organic N, NH4-N (ammonium), NO3-N (nitrate), NO2-N (nitrite), and N associated with sediment as exchangeable NH4-N or organic-N. Nitrogen cycling is extremely dynamic and complex, especially the microbiological processes responsible for mineralization, fixation and denitrification of soil nitrogen. Generally, in soils that are not waterlogged, soil N (held as protein in plant matter) and fertilizer-N are microbiologically transformed to NH4 (ammonium) through the process of ammonification. The ammonium ion is oxidized by two groups of bacteria (Nitrosomonas and Nitrobacter) to NO3 with an unstable intermediate NO2 product in a process called nitrification. Urea is readily hydrolysed to ammonium. Denitrification occurs under anoxic conditions such as wetlands where NO3 is reduced to various gaseous forms. The N cycle is largely controlled by bacteria, hence the rate of N cycling is dependent upon factors such as soil moisture, temperature, pH, etc. NO3 is the end-product of aerobic N decomposition and is always dissolved and mobile. From a water quality perspective, the ammonium ion (NH4) can be adsorbed to clay particles and moved with soil during erosion. More importantly, however, NH4 and NO3 are soluble and are mobilized through the soil profile to groundwater during periods of rain by the process of leaching. NO3 is also observed in surface runoff during rainfall events. Prevention of nitrogen pollution of surface and groundwater depends very much on the ability to maintain NO3 in soil only up to the level that can be taken up by the crop, and to reduce the amount of NO3 held in the soil after harvesting. The processes described above are depicted in Figure 11. In contrast, the behaviour of phosphorus is quite simple. Phosphorus can exist in a variety of forms: as mineral (generally apatite) phosphorus (AP); non-apatite inorganic-P (NAIP); organic-P (OP - bound up with carbon and oxygen in plant matter); and as dissolved soluble reactive ortho-P (SRP). The phosphorus species AP, NAIP and OP are associated with the particulate phase. In studies of phosphorus movement from agricultural lands the largest amount is sorbed onto clay materials and transported as erosion products. SRP is readily available to aquatic plants to the point where measured SRP in surface water may only represent a residual amount after most of the SRP has been taken up by plant life. Consequently, in aquatic studies, the focus is often on the sediment-associated forms of P as these tend to dominate total phosphorus flux. The NAIP fraction is considered to be available to plant roots and is rapidly solubilized under conditions of anoxia in the bottom of lakes and reservoirs. It is for this reason that lake sediments can represent a very large internal (autotrophic) load of phosphorus which is recycled into the water column during periods of bottom anoxia. This load can be so large that, without attention to lake sediment remediation, phosphorus management programmes in tributaries can be quite meaningless. The relative losses of N and P to groundwater are illustrated in Table 15 where it is seen that P losses are generally smaller relative to the much more soluble N. Indeed, insofar as maize is the most heavily fertilized crop, the leaching of nitrogen is especially noticeable. The point versus non-point source dilemma The dilemma in many countries is to ascertain the role of agriculture relative to the impacts of (often untreated) municipal sewage. In a large number of countries the database required to make this distinction is lacking and frustrates the development of a rational pollution abatement programme and inhibits cost-effective investment in control measures. In developing countries it makes sense that the focus should initially be on point source control; however, it has been the experience in the developed countries that point source control for nutrients has not had the desired level of environmental benefit until agricultural control measures were seriously addressed. It is significant that the trend of fertilizer usage worldwide has been one of huge increases in the past 40 years suggesting that, in the absence of major changes in land use to control fertilizer runoff in large parts of the world, one may expect that agriculture will be responsible for an ever-increasing contribution to surface water pollution. The observations reported by Quirós (see Box 5) for the La Plata basin are indicative of the difficulty in segregating the effects of agriculture from other sources. In the Great Lakes of North America some $10 million dollars were spent between 1970 and 1980 to quantify the relative impacts of point versus non-point sources. That exercise proved enormously successful and specific policies were adopted for nutrient control in each lake basin that reflected the relative contributions from each type of source. Sludge management The investigation of eutrophication of surface water by agriculture must adopt a pragmatic management perspective. Of value to agriculture is the perspective adopted by the OECD study of eutrophication. That study focused on the following aspects: · The qualitative assessment of the trophic state of bodies of water in terms of a few easily measured parameters. · The dependence of this state on nutritional conditions and nutrient load. · Translation of these results to the needs of eutrophication control for management. The progression of these aspects is interesting in that the focus is on easily measurable state of the water body, followed by a determination of the extent to which the state is a product of nutrient loads, then the degree to which loads may be manipulated to achieve a desired trophic state that is determined by water use. Prediction of water quality impacts of fertilizers and related land management practices is an essential element of site-specific control options and for the development of generic approaches for fertilizer control. Prediction tools are essentially in the form of models, many of which are contained in Table 7. BOX 5: SEGREGATING AGRICULTURAL FROM INDUSTRIAL IMPACTS ON WATER QUALITY OF THE LA PLATA BASIN, SOUTH AMERICA In his report on impacts on the fishery in the la Plata river system, Quirós (1993) provided a comprehensive summary of observed symptoms. He admitted to the difficulty in providing evidence for cause and effect in this large river system. Nevertheless, he concluded that the evidence was consistent with that of a regulated river-floodplain system impacted from toxic substances used in agriculture and industry. Observed Symptoms Fruit and seed eater species of the genera Colossoma and Brycon and the big catfish Paulicea lutkenii have practically disappeared from the commercial catch in the lower Paraná river, and also from the catches in the La Plata and Uruguay rivers. Fish species of marine lineage of the genera Basilichthys and Lycengraulis, usually moving upstream from the estuary in winter, have practically disappeared from the commercial catches in the middle Paraná. The commercial catches of the pelagic top predator Salminus maxillosus have been decreasing since the late 1940s in all the lower basin, though its commercial catch has been highly restricted. Populations of most of the migratory fish species are severely diminished in the middle and upper Uruguay river. Relatively high levels of agricultural pesticides and heavy metals were detected in fish tissues. Periodic massive fish mortalities were reported in the lower Paraná delta and the La Plata river. Low water oxygen levels and massive fish mortalities were detected in the lower Paraguay river, and discharges of high organic matter content effluents from the agricultural industry have increased in the upper basin. The exotic Cyprinus carpio was the most important species in biomass in the experimental catches in the La Plata river, and its catch has been increasing in the middle Paraná. Maximum size of catch of the big catfish of the genera Pseudoplatystoma has been decreasing for the last three decades in the lower middle Paraná. The conflicting situations between recreational and commercial fishermen have been increasing, and the trophy size of Salminus has been decreasing at the confluence of the Paraná and Paraguay rivers, though total fishing effort seems not to have increased. Source: Quirós (1993). Mineral fertilizers The response to the need to control leaching and runoff of nutrients and contamination of soils and water by heavy metals has been variable in Europe. Control measures are part of the larger issue of mineral and organic fertilizer usage. FAO/ECE (1991) summarized the types of voluntary and mandated controls in Europe that apply to mineral fertilizers as: · Taxes on fertilizer. · Requirement for fertilizer plans. · Preventing the leaching of nutrients after the growing season by increasing the area under autumn/winter green cover, and by sowing crops with elevated nitrogen · Promoting and subsidizing better application methods, developing new, environmentally sound fertilizers, and promoting soil testing. · Severely limiting the use of fertilizers in e.g. water extraction areas and nature protection areas. In any location where intensive agriculture and/or livestock farming produces serious risks of nitrogen pollution, Ignazi (1993) recommended the following essential steps that are taken at the farm level: 1. Rational nitrogen application: To avoid over-fertilization, the rate of nitrogen fertilizer to be applied needs to be calculated on the basis of the "crop nitrogen balance". This takes into account plant needs and amount of N in the soil. 2. Vegetation cover: As far as possible, keep the soil covered with vegetation. This inhibits build-up of soluble nitrogen by absorbing mineralized nitrogen and preventing leaching during periods of rain. 3. Manage the period between crops: Organic debris produced by harvesting is easily mineralized into leachable N. Steps to reduce leachable N includes planting of "green manure" crops, and delaying ploughing of straw, roots and leaves into the soil. 4. Rational irrigation: Poor irrigation has one of the worst impacts on water quality, whereas precision irrigation is one of the least polluting practices as well as reducing net cost of supplied water. 5. Optimize other cultivation techniques: Highest yields with minimum water quality impacts require optimization of practices such as weed, pest and disease control, liming, balanced mineral fertilizers including trace elements, etc. 6. Agricultural Planning: Implement erosion control techniques (see Chapter 2) that complement topographic and soil conditions. Voluntary and legislated control measures in Europe are intended to have the following benefits: · Reduce the leaching of nutrients · Reducing emissions of ammonia · Reducing contamination by heavy metals The nature of these measures varies by country; however FAO/ECE (1991) have summarized the types of voluntary and mandated control as: · Maximum numbers of animals per hectare based on amount of manure that can be safely applied per hectare of land. · Maximum quantities of manure that can be applied on the land is fixed, based on the N and P content of the manure. · Holdings wishing to keep more than a given number of animals must obtain a license. · The periods during which it is allowed to apply manure to the land have been limited, and it is obligatory to work it into the ground immediately afterwards. · Establishment of regulations on minimum capacity for manure storage facilities. · Establish fertilizer plans. Sludge management Sludge is mentioned here only insofar as the spreading of sludge from municipal wastewater treatment facilities on agricultural land is one method used to get rid of municipal sludge in a way that is perceived to be beneficial. The alternatives are incineration and land fill. FAO/ECE (1991) include sludge within the category of organic fertilizers but note that sludge often contains unacceptable levels of heavy metals. Pollution of water by sludge runoff is otherwise the same as for manure noted above. Economics of control of fertilizer runoff Nutrient loss is closely associated with rainfall-runoff events. For phosphorus, which tends to be associated with the solid phase (sediment), runoff losses are directly linked to erosion. Therefore the economics of nutrient control tend to be closely tied to the costs of controlling runoff and erosion. Therefore, this will be treated briefly here. In particular, it is useful to examine the economic cost of nutrient runoff which must be replaced by fertilizers if the land is to remain productive. The link between erosion, increasing fertilizer application, and loss of soil productivity is very direct in many countries. In the Brazilian state of Paraná where agriculture is the base of the state economy, Paraná produces 22% of the national grain production on only 2.4% of the Brazilian territory. Agricultural expansion in Paraná occurred mainly in the period 1950-1970 and was "characterized by short-term agricultural systems leading to continuous and progressive environmental degradation as a result of economic policies and a totally inappropriate land parcelling and marketing system..." (Andreoli, 1993). Erosion has led to extensive loss of top soil, large-scale gullying (Figure 4), and silting of ditches and rivers. The use of fertilizers has risen as a consequence, up 575% over the period 1970-1986 and without any gain in crop yields. Loss of N-P-K from an average erosion of 20 t/ha/yr represents an annual economic loss of US$242 million in nutrients. FIGURE 12: Water-based aquaculture in the Lakes Region of southern Chile Analysis by Elwell and Stocking (1982) of nutrient loss arising from erosion in Zimbabwe shows similar significant economic losses in African situations. Stocking (FAO, 1986), applying data collected in the 1960s by Hudson to the soil use map of Zimbabwe, calculated an annual loss of 10 million tonnes of nitrogen and 5 million tonnes of phosphorus annually as a consequence of erosion (cited by Roose in FAO, 1994a). Roose (FAO, 1994a) also cites losses of 98 kg/ha/yr of nitrogen, 29 kg/ha/yr of phosphorus, 39 kg/ha/yr of lime and 39 kg/ha/yr of magnesium from soils of lower Côte d'Ivoire as a result of erosion. This loss is so severe that compensation requires 7 tonnes of fresh manure annually, plus 470 kg of ammonium sulphate, 160 kg of superphosphate, 200 kg dolomite and 60 kg of potassium chloride per hectare per year. Roose notes that it is not surprising that the soil is exhausted after only two years of traditional agriculture. Furthermore, these losses do not take into account additional losses due to harvesting and runoff. Roose summarizes by stating that action against soil erosion is essential in order to manage what he describes as a "terrible" chemical imbalance in soils caused by soil erosion. Estimates of phosphorus loss by erosion in the Republic of South Africa (Du Plessis, 1985) are R26.4 M/yr (US$ 10.5 million). Economic losses tend to be higher in tropical countries where soils, rainfall and agricultural practices are more conducive to erosion, and reported rates of erosion are much above average. The World Bank (1992) reported that extrapolation from test-plots of impacts of soil loss on agricultural productivity, indicates some 0.5-1.5% loss of GDP annually for countries such as Costa Rica, Malawi, Mali and Mexico. These losses do not include offsite costs such as reservoir infilling, river sedimentation, damage to irrigation systems, etc. Soil fertility is a complex issue and nutrient loss is not necessarily nor always a consequence of erosion. Erosion and soil loss is the end member of a variety of physical, vegetative and nutrient factors that lead to soil degradation. Global patterns of fertilizer application, as reported by Joly (1993), indicate however that rapidly rising levels of fertilizer utilization are required merely to maintain soil productivity from a variety of types of loss, including losses due to erosion and, more generally, to soil degradation. In a study of 17 agricultural sub-watersheds in the Lake Balaton district of Hungary, Jolankai (1986) measured and modelled N and P runoff from a variety of agricultural land uses. He calculated that a selection of control measures (mainly erosion control) would reduce phosphorus loss by 52.8% at a cost of US$ 2500 per ha in remediation measures (in 1986). Aquaculture Aquaculture is a special case of agricultural pollution. There are two main forms: land-based and water-based systems (Figure 12). Effluent controls are possible on land-based systems, however water-based systems present particular problems. Aquaculture is rapidly expanding in most parts of the developed and developing world, both in freshwater and marine environments. In contrast, coastal fisheries in most countries are declining. The environmental impact is primarily a function of feed composition and feed conversion (faecal wastes), plus assorted chemicals used as biocides, disinfectants, medicines, etc. Wastage of feed (feed not taken up by the fish) is estimated to be 20% (Ackefors and Enell, 1992) in European aquaculture. Waste feed and faecal production both add substantial nutrient loadings to aquatic systems. Additional environmental problems include risk of disease and disease transfer to wild fish, introduction of exotic species, impacts on benthic communities and on the eutrophication of water, interbreeding of escaped cultured fish with wild fish with consequent genetic change in the wild population. Traditional integrated aquaculture systems, as in China, where sewage-fish culture is practised, can be a stabilizing influence in the entire ecosystem (Rosenthal, 1992). This is recommended, especially in developing countries where water and resources are scarce or expensive. Problems of restoration of eutrophic lakes Eutrophic and hypertrophic lakes tend to be shallow and suffer from high rates of nutrient loadings from point and non-point sources. In areas of rich soils such as the Canadian prairies, lake bottom sediments are comprised of nutrient-enriched soil particles eroded from surrounding soils. The association of phosphorus with sediment is a serious problem in the restoration of shallow, enriched lakes. P-enriched particles settle to the bottom of the lake and form a large pool of nutrient in the bottom sediments that is readily available to rooted plants and which is released from bottom sediments under conditions of anoxia into the overlying water column and which is quickly utilized by algae. This phosphorus pool, known as the "internal load" of phosphorus, can greatly offset any measures taken by river basin managers to control lake eutrophication by control of external phosphorus sources from agriculture and from point sources. Historically, dredging of bottom sediments was considered the only means of remediating nutrient-rich lake sediments, however, modern technology now provides alternative and more cost-effective methods of controlling internal loads of phosphorus by oxygenation and by chemically treating sediments in situ to immobilize the phosphorus. Nevertheless, lake restoration is expensive and must be part of a comprehensive river basin management programme.

i don't know

What is the name of the liquid rock which pours from a volcano?

What is the name of the liquid rock which pours from a volcano? - YouTube What is the name of the liquid rock which pours from a volcano? Want to watch this again later? Sign in to add this video to a playlist. Need to report the video? Sign in to report inappropriate content. The interactive transcript could not be loaded. Loading... Rating is available when the video has been rented. This feature is not available right now. Please try again later. Published on Aug 1, 2013 This improves the knowledge of the children indirectly as they never know that they are learning. - Category

Lava

What is the term applied to the process of gathering together weather forecasts from various recording stations?

Volcanoes: The Nature of Volcanoes The Nature of Volcanoes Volcanoes are mountains but they are very different from other mountains; they are not formed by folding and crumpling or by uplift and erosion. Instead, volcanoes are built by the accumulation of their own eruptive products -- lava, bombs (crusted over ash flows, and tephra (airborne ash and dust). A volcano is most commonly a conical hill or mountain built around a vent that connects with reservoirs of molten rock below the surface of the Earth. The term volcano also refers to the opening or vent through which the molten rock and associated gases are expelled. Driven by buoyancy and gas pressure the molten rock, which is lighter than the surrounding solid rock forces its way upward and may ultimately break though zones of weaknesses in the Earth's crust. If so, an eruption begins, and the molten rock may pour from the vent as non-explosive lava flows, or if may shoot violently into the air as dense clouds of lava fragments. Larger fragments fall back around the vent, and accumulations of fall-back fragments may move downslope as ash flows under the force of gravity. Some of the finer ejected materiaIs may be carried by the wind only to fall to the ground many miles away. The finest ash particles may be injected miles into the atmosphere and carried many times around the world by stratospheric winds before settling out.    Fountaining lava and volcanic debris during the 1959 Kilauea Iki eruption of Kilauea Volcano, Hawaii. Molten rock below the surface of the Earth that rises in volcanic vents is known as magma, but after it erupts from a volcano it is called lava. Originating many tens of miles beneath the ground, the ascending magma commonly contains some crystals, fragments of surrounding (unmelted) rocks, and dissolved gases, but it is primarily a liquid composed principally of oxygen, silicon, aluminum, iron, magnesium, calcium, sodium, potassium, titanium, and manganese. Magmas also contain many other chemical elements in trace quantities. Upon cooling, the liquid magma may precipitate crystals of various minerals until solidification is complete to form an igneous or magmatic rock. The diagram below shows that heat concentrated in the Earth's upper mantle raises temperatures sufficiently to melt the rock locally by fusing the materials with the lowest melting temperatures, resulting in small, isolated blobs of magma. These blobs then collect, rise through conduits and fractures, and some ultimately may re-collect in larger pockets or reservoirs ("holding tanks") a few miles beneath the Earth's surface. Mounting pressure within the reservoir may drive the magma further upward through structurally weak zones to erupt as lava at the surface. In a continental environment, magmas are generated in the Earth's crust as well as at varying depths in the upper mantle. The variety of molten rocks in the crust, plus the possibility of mixing with molten materials from the underlying mantle, leads to the production of magmas with widely different chemical compositions.    An idealized diagram of a volcano in an oceanic environment (left) and in a continental environment (right). If magmas cool rapidly, as might be expected near or on the Earth's surface, they solidify to form igneous rocks that are finely crystalline or glassy with few crystals. Accordingly, lavas, which of course are very rapidly cooled, form volcanic rocks typically characterized by a small percentage of crystals or fragments set in a matrix of glass (quenched or super-cooled magma) or finer grained crystalline materials. If magmas never breach the surface to erupt and remain deep underground, they cool much more slowly and thus allow ample time to sustain crystal precipitation and growth, resulting in the formation of coarser grained, nearly completely crystalline, igneous rocks. Subsequent to final crystallization and solidification, such rocks can be exhumed by erosion many thousands or millions of years later and be exposed as large bodies of so-called granitic rocks, as, for example, those spectacularly displayed in Yosemite National Park and other parts of the majestic Sierra Nevada mountains of California.     Two Polynesian terms are used to identify the surface character of Hawaiian lava flows. Aa, a basalt with a rough, blocky appearance, much like furnace slag, is shown at the left. Pahoehoe, a more fluid variety with a smooth, satiny and sometimes glassy appearance, is shown at the right. Lava is red hot when it pours or blasts out of a vent but soon changes to dark red, gray, black, or some other color as it cools and solidifies. Very hot, gas-rich lava containing abundant iron and magnesium is fluid and flows like hot tar, whereas cooler, gas-poor lava high in silicon, sodium, and potassium flows sluggishly, like thick honey in some cases or in others like pasty, blocky masses. All magmas contain dissolved gases, and as they rise to the surface to erupt, the confining pressures are reduced and the dissolved gases are liberated either quietly or explosively. If the lava is a thin fluid (not viscous), the gases may escape easily. But if the lava is thick and pasty (highly viscous), the gases will not move freely but will build up tremendous pressure, and ultimately escape with explosive violence. Gases in lava may be compared with the gas in a bottle of a carbonated soft drink. If you put your thumb over the top of the bottle and shake it vigorously, the gas separates from the drink and forms bubbles. When you remove your thumb abruptly, there is a miniature explosion of gas and liquid. The gases in lava behave in somewhat the same way. Their sudden expansion causes the terrible explosions that throw out great masses of solid rock as well as lava, dust, and ashes. The violent separation of gas from lava may produce rock froth called pumice. Some of this froth is so light--because of the many gas bubbles--that it floats on water. In many eruptions, the froth is shattered explosively into small fragments that are hurled high into the air in the form of volcanic cinders (red or black), volcanic ash (commonly tan or gray), and volcanic dust.    During the 1959 eruption of Kilauea Iki, fountaining lava and volcanic debris completely blocked several of the roads in the Hawaii Volcanoes National Park.  

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What kind of natural phenomenon 'meanders'?

15 weird natural phenomena [PICS] - Matador Network 15 weird natural phenomena [PICS] by Sarah Park August 27, 2010 Sarah Park brings us some of the most dangerous, beautiful, and downright weird wonders of the natural world. 1 Bioluminescent red tide When conditions are just right, ocean phytoplankton reproduce like bunnies, creating a thick, visible layer near the surface. These algae blooms (a.k.a "red tide") might look disgusting during the day, but in parts of California and other places where the bioluminescent variety of Noctiluca scintillans bloom, red tide nights look out of this world. This particular variety of phytoplankton glows blue when agitated, transforming the dark ocean into a giant lava lamp. Watch the waves light up as they crash, run across the sand to see the ground glow under your feet, or dive in to be surrounded by the bizarre Timex-y glow. N. scintillans is also the culprit behind the Bioluminescent Bays in Puerto Rico . Photo: catalano82 2 Foxfire During the late summer, a faint, eerie glow can be seen in forests around the world, where bioluminescent mushrooms grow on moist, rotting bark. The greatest diversity of foxfire occurs in the tropics, where moist forests encourage fungal growth. The newest varieties of glow-in-the-dark mushrooms were introduced to the world just last year, after being collected from Ribeira Valley Tourist State Park near Sao Paulo, Brazil. To up your chances of seeing this one, hunt in the forest during its wettest season and move as far as possible from any artificial light sources. And f you happen to see a patch of glowing shrooms, don't even think about it -- they're not that kind of mushroom . Photo: Ylem 3 Fire rainbow Another summertime occurrence, fire rainbows appear when sunlight hits frozen ice crystals in high-altitude cirrus clouds. Because the fire rainbow actually involves no rain at all, scientists would rather we refer to this occurrence by its much less fun, but much more accurate title: the circumhorizonal arc. Since the arc requires both the presence of cirrus clouds and for the sun to be extremely high in the sky, it's much more likely to be seen at latitudes closer to the equator. Conditions might be right for a fire rainbow in Los Angeles six months out of the year, but in a more northern city like London, that window drops to a mere two months. The photo above was taken in West Virginia . Photo: Jeff Kubina Intermission 4 Nacreous clouds For those of you a bit farther away from the equator, there's still plenty to see in the sky. Nacreous clouds (also called mother-of-pearl clouds) are extremely rare, but unmistakeable in the dark hours before dawn or after sunset. Because of their extremely high altitudes, they reflect sunlight from below the horizon, shining it down brightly, in stark comparison to the regular ol' dark clouds in the troposphere. The lower stratosphere, where nacreous clouds live, is so dry that it often prevents cloud formation, but the extreme cold of polar winters makes this beautiful phenomenon possible. Captured best during winter at high latitudes, nacreous clouds have been spotted in Iceland , Alaska, Northern Canada, and very rarely, farther south in England. Photo: Thomas Larsen Røed 5 Snow rollers Snow rollers are formed when a thick layer of snow falls on top of a layer of ice. If the temperature and wind speed are right, chunks of snow can break loose and start rolling. As they're blown along the ground like wintry tumbleweeds, they pick up additional snow along the way. The inner layers are often weaker and less compact, allowing them to be blown easily away by the wind, leaving a large, naturally formed snow donut. Because of the precise temperature and wind speeds required to create this effect, snow rollers are a rare sight, but have made headlines with their appearances in parts of North America and the UK . Photo: jah~ 6 Columnar basalt A natural volcanic formation, columnar basalt has a seemingly man-made appearance. The (mostly) hexagonal columns form naturally as thick lava rapidly cools, contracting and creating cracks in the surface of the new rock. These unusual geological formations can be seen across the globe. Two of the most notable examples include the Giant's Causeway in Ireland, and Devil's Postpile in California (pictured above). Photo: dwolfgra 7 Raining animals This phenomenon has been reported in locations worldwide for centuries, with most cases involving fish, frogs, or other small aquatic animals. Despite being extremely rare and lacking in credible eyewitness accounts, most incidents are explainable. Waterspouts (think tornadoes made of water) are the go-to culprit, as their high winds are capable of lifting small animals out of the water, carrying them far distances before dropping them unceremoniously on your head. Considering this, I'd recommend heading closer to large bodies of water during an extremely heavy storm to increase odds of bearing witness to this truly bizarre phenomenon. But, seriously, bring a poncho or something. Photo: Matthew Hoelscher 8 Asperatus clouds Asperatus clouds are so rare they managed to escape classification until 2009. Ominous and stormy as they appear, these clouds often break up rather quickly, without producing a storm. As with most other undulating cloud types, these clouds are formed when turbulent winds or colliding air masses whip up the bottoms of the cloud layer into fancy shapes and formations. More common in the plains of the United States (try Iowa ), asperatus clouds are at their weird and swirly best during the morning or midday hours after a thunderstorm. Photo: B.J. Bumgarner 9 Green flash The famed and elusive Green Flash is a rare meteorological phenomenon that occurs at sunset and sunrise. During these times, the sun's light travels through more of the earth's atmosphere to reach your eye, creating a prism effect. Yeah, the explanation is definitely more dull than many of the maritime legends surrounding the phenomenon, but consider yourself very lucky if you're able to witness this event. To increase your chances, watch the sun set (or rise) over a long and uninterrupted horizon on a very clear day. The ocean horizon works well for this, as will a prairie, or the horizon line while inside an airplane. The flash lasts only a fraction of a second, so don't blink! Photo: Mila Zinkova Intermission 10 Sun dogs When the sun is near the horizon and ice crystals are present in the air, look up to see a pair of bright spots sitting on either side of the sun. Always to the right and the left along the horizon line, these dogs loyally follow the sun across the sky. While this atmospheric phenomenon can occur whenever, wherever , the effect is usually quite subtle. When sunlight passes through cirrus clouds (or other types of ice clouds) at just the right angle, however, these spots can appear as bright as the sun itself. The brightest occur when the sun is low in the sky in colder regions. This photo shows a sun dog at the South Pole. Photo: Lt. Cindy McFee 11 Double rainbow If there were any atmospheric phenomenon that could bring a grown man to tears , it's this one. So, "WHAT DOES IT MEAN?!?!?!?" Well, it means pretty much the same thing as a regular rainbow. Only, on occasion, sunlight reflects in a raindrop not once, but twice, creating a secondary rainbow outside of the much brighter primary arc. The best views of this phenomenon occur when the sky is still dark with rainclouds, as the gray background helps the much dimmer colors of the secondary arc appear. Double rainbow, all the way! Photo: Tim Kelley 12 Striped iceberg Icebergs aren't exclusively monotone. A few nonconformists come in various colored stripes, standing out against arctic whites and blues. As water melts and refreezes on an iceberg over time, dirt and other particles can become trapped between new layers of ice, creating multicolored stripes across its surface. A variety of colors can appear. Blue stripes occur when water gets trapped between layers of ice and freezes so quickly that air bubbles cannot form. Once icebergs break off and fall into the ocean, algae or other materials present in the water can create green or yellow stripes. Up your chances of viewing striped bergs by heading south to Antarctica . Photo: Jeff McNeill 13 Catatumbo lightning Still a relatively mysterious occurrence, the Catatumbo lighting in Venezuela is known as the everlasting storm. The seemingly non-stop cloud-to-cloud lightning can be easily seen from a distance, and has long been celebrated for its ability to assist sailors with navigation. Since the Catatumbo lighting does its thing approximately 140-160 nights per year, your chances of viewing it are quite good. It occurs very specifically in one area -- the mouth of the Catatumbo River and around Maracaibo Lake. Photo: Thechemicanengineer 14 Gravity wave Waves apparently aren't restricted to large bodies of water or the stands at sporting events -- they can happen, albeit rarely, in the sky as well. When air is pushed up into a more stable layer of atmosphere, it can cause a ripple effect, just like tossing a rock into a pond. For a gravity wave to occur, there must be a disturbance in the atmosphere, such as an updraft of a thunderstorm. Recent studies indicate that gravity waves have the power to concentrate and intensify tornados, so if you're lucky (or unlucky) enough to view the undulating cloud formations firsthand, I'd suggest seeking shelter soon after! Iowa would be a good place to start the hunt. Photo: NASA 15 Moeraki Boulders Known as the Moeraki Boulders, these spherical stones have been naturally excavating themselves one by one from their mudstone beds on the New Zealand coast. Erosion uncovers these giants, but it isn't responsible for their spherical shape. Instead, these boulders are said to have been created millions of years ago on the ocean floor in a process similar to the formation of oyster pearls -- layers of sediment and material crystallizing around a central core. Over the course of millions of years, they grew to the immense sizes seen today. The boulders can be found on Koekohe Beach, New Zealand. Photo: Geof Wilson Like this Article

The River

What is the collective name for rain hail, snow, and sleet?

10 Most Fascinating Natural Phenomena (amazing nature, natural scences, amazing nature pictures) - ODDEE 10 Most Fascinating Natural Phenomena 4/28/2009 1 Aurora Borealis Undoubtedly one of the most beautiful events to occur in our world, the Aurora Borealis , also known as the Northern Lights, has both astounded and amazed people since it was first discovered. This phenomenon ocurrs when the sun gives off high-energy charged particles (also called ions) that travel out into space at speeds of 300 to 1200 kilometres per second. A cloud of such particles is called a plasma. The stream of plasma coming from the sun is known as the solar wind. As the solar wind interacts with the edge of the earth’s magnetic field, some of the particles are trapped by it and they follow the lines of magnetic force down into the ionosphere, the section of the earth’s atmosphere that extends from about 60 to 600 kilometers above the earth’s surface. When the particles collide with the gases in the ionosphere they start to glow, producing the spectacle that we know as the auroras, northern and southern. 2 Mammatus Clouds Also known as mammatocumulus, meaning "bumpy clouds", they are a cellular pattern of pouches hanging underneath the base of a cloud. Composed primarily of ice, Mammatus Clouds can extend for hundreds of miles in each direction, while individual formations can remain visibly static for ten to fifteen minutes at a time. True to their ominous appearance, mammatus clouds are often harbingers of a coming storm or other extreme weather system. 3 Red Tides More correctly known as an algal bloom, the so-called Red tide is a natural event in which estuarine, marine, or fresh water algae accumulate rapidly in the water column and can convert entire areas of an ocean or beach into a blood red color. This phenomena is caused by high levels of phytoplankton accumulating to form dense, visible clouds near the surface of the water. While some of these can be relatively harmless, others can be harbingers of deadly toxins that cause the deaths of fish, birds and marine mammals. In some cases, even humans have been harmed by red tides though no human exposure are known to have been fatal. While they can be fatal, the constituent phytoplankton in ride tides are not harmful in small numbers. 4 Penitentes These amazing ice spikes, generally known as penitentes due to their resemblance to processions of white-hooded monks, can be found on mountain glaciers and vary in size dramatically: from a few centimetres to 5 metres in height. Initially, the sun’s rays cause random dimples on the surface of the snow. Once such a dimple is formed, sunlight can be reflected within the dimple, increasing the localized sublimation. As this accelerates, deep troughs are formed, leaving peaks of ice standing between them. 5 Sailing Stones The mysterious moving stones of the packed-mud desert of Death Valley have been a center of scientific controversy for decades. Rocks weighing up to hundreds of pounds have been known to move up to hundreds of yards at a time. Some scientists have proposed that a combination of strong winds and surface ice account for these movements. However, this theory does not explain evidence of different rocks starting side by side and moving at different rates and in disparate directions. Moreover, the physics calculations do not fully support this theory as wind speeds of hundreds of miles per hour would be needed to move some of the stones. 6 Supercells Supercell is the name given to a continuously rotating updraft deep within a severe thunderstorm (a mesocyclone) and looks downright scary. They are usually isolated storms, which can last for hours, and sometimes can split in two, with one storm going to the left of the wind and one to the right. They can spout huge amounts of hail, rain and wind and are often responsible for tornados, though they can also occur without tornados. Supercells are often carriers of giant hailstones and although they can occur anywhere in the world they’re most frequent in the Great Plains of the US. 7 Fire Whirls A fire whirl , also known as fire devil or fire tornado, is a rare phenomenon in which a fire, under certain conditions --depending on air temperature and currents--, acquires a vertical vorticity and forms a whirl, or a tornado-like effect of a vertically oriented rotating column of air. Fire whirls often occur during bush fires. Vertical rotating columns of fire form when the air currents and temperature are just right, creating a tornado-like effect. They can be as high as 30 to 200 ft tall and up to 10 ft wide but only last a few minutes, although some can last for longer if the winds are strong. 8 Ice Circles A rare phenomenon usually only seen in extremely cold countries, scientists generally accept that Ice Circles are formed when surface ice gathers in the center of a body of water rather than the edges. A slow moving river current can create a slow turning eddy, which rotates, forming an ice disc. Very slowly the edges are ground down until a gap is formed between the eddy and the surrounding ice. These ice circles have been seen with diameters of over 500 feet and can also at times be found in clusters and groups at different sizes. 9 Gravity Waves The undulating pattern of a Gravity Wave is caused by air displaced in the vertical plain, usually as a result of updrafts coming off the mountains or during thunderstorms. A wave pattern will only be generated when the updraft air is forced into a stable air pocket. The upward momentum of the draft triggers into the air pocket causes changes in the atmosphere, altering the fluid dynamics. Nature then tries to restore the fluid changes within the atmosphere, which present in a visible oscillating pattern within the cloud. (Photo by: NASA ) 10 Hums " The Hum " is the common name of a series of phenomena involving a persistent and invasive low-frequency humming noise not audible to all people. Hums have been reported in various geographical locations. In some cases a source has been located. A well-known case was reported in Taos, New Mexico, and thus the Hum is sometimes called the Taos Hum. They have been reported all over the world, especially in Europe: a Hum on the Big Island of Hawaii, typically related to volcanic action, is heard in locations dozens of miles apart. The Hum is most often described as sounding somewhat like a distant idling diesel engine. Difficult to detect with microphones, its source and nature are unknown. From the Web

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What is the hardest natural substance known?

What is the hardest natural substance known? | Flexiguru What is the hardest natural substance known? Class 10th Chemistry Mahesh Kumar The hardest natural substance is diamond which is an allotrope of carbon. It has superlative physical qualities which originated from the strong covalent bonding between its atoms. The carbon atoms are arranged in a variation of the face-centred cubic crystal structure called a diamond lattice. Kamal Sharma Diamond. It's carbon packed extremely tightly together, which makes it pretty much unbreakable. This is also part of the reason why diamonds are so highly valued no one wants their diamond ring to fall to the ground and shatter into a million pieces. Diamond is currently thought to be the hardest natural material on Earth, having a hardness of ten out of ten on the Mohs scale of mineral hardness. Diamond is made up of carbon atoms which share strong covalent bonds (where electrons are shared between atoms) and are equally spaced in a lattice arrangement. These atoms cannot move, which is what makes diamonds so hard.

Diamond

What is the collective noun for crows?

Top 10 Hardest Materials | REALITYPOD Top 10 Hardest Materials Anonyzious 30 August, 2011 Diamond is widely believed to be the hardest known material to man, but is it really the case? What are the other hard materials apart from diamond? Well, today our list will answer these questions for you. No 10. Alumina Alumina is a common name for Aluminum Oxide, which is an amphoteric oxide and is more even more commonly known as Corundum in its crystalline form. Alumina in its alpha phase is the strongest and stiffest of the oxide ceramics; alpha phase is the most stable hexagonal phase achieved at high temperatures. Alumina is used in gas laser tubes, electronic substrates, ballistic armor and grinding media. Varieties of alumina exist and the more known of them are Ruby and Sapphire which are categorized based on impurities as well as color. No 9. Boron carbide This is an extremely hard ceramic material most notably used in tank armor and bulletproof vests. It finds its use in padlocks, neutron absorber in nuclear reactors, high energy fuel for solid fuel Ramjets and anti-ballistic armor plating. No 8. Zirconium carbide Appearing as a gray metallic powder Zirconium carbide is an extremely hard refractory ceramic material, commercially used in tool bits for cutting tools. Zirconium Carbide along with Zirconium Oxide are known as modern ceramics and is extremely hard, wear resistant, and chemically inert. No 7. Titanium diboride Titanium Diboride is an extremely hard material with very good high temperature corrosion resistance. It is a ceramic and therefore is a material of high interest due to being electrically conductive. Titanium diboride is more than three times strong the strongest steel available. Prev1 of 3 Next

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What is the maximum speed of a garden snail: 0.03 mph, 0.3 mph, or 3 mph?

Speed of a Snail - The Physics Factbook Speed of a Snail The World Almanac and Book of Facts 1999. New Jersey: Primedia, 1998: 572. "Garden snail, 0.03 mph" 0.013 m/s Branson, Branley Allan. World & I. 11, 5 (May 1996): 166. "A large banana slug has been observed to cover 6.5 inches in 120 minutes. At that rate, a tortoise would seem fleet-footed." 0.000023 m/s The Guinness Book of World Records 1998. Stanford, CT: Guinness, 1997: 144. "A garden snail named Archie, owned by Carl Branhorn of Pott Row, England, covered a 13 inch course in 2 minutes at the 1995 World Snail Racing Championships, held in Longhan, England." 0.0028 m/s Snails and slugs are gastropods, which make up the largest class of mollusks with more than 60,000 species. Most of these species can be identified by their shells. Some dwell in ocean, others in the freshwater of rivers, ponds, and lakes. Land snails abound in tropical jungles and in damp temperate regions. All of them need calcium carbonate for building their shells, and so are not common in sandy soil. Slugs differ from snails in that they generally have only a small internal shell. Snails move by sliding on their single foot. Specialized glands in the foot secrete mucus, which lubricates the path over which the snail crawls. Snails can only crawl. Even those that live in water can't swim. As they crawl they secrete a slime to help themselves move across surfaces. Snails and slugs travel at speeds that vary from slow (0.013 m/s) to very slow (0.0028 m/s). The snail's head bears the mouth opening and one or two pairs of tentacles. The eyes are located at the base of the tentacles. Most snails live off plants and dead organic matter, although a few are carnivorous. Their radula is a tongue-like projection of their mouth which is lined with small sharp teeth. Some snails obtain food by using their radula to drill holes in the shells of other mollusks. Freshwater snails and land snails have been eaten by people since prehistoric times. Today they are still regarded as a delicacy in many countries. The market supply comes largely from snails that are raised in captivity on special farms in southern France, Italy, and Spain. About 10,000 snails can be kept in a 9 square meter area, where they are fed meal, vegetables, and bran. Angie Yee -- 1999

0 03 mph

What common mineral is formed by the fossilization of vegetation?

Slowest Animal World Record Contact Us Slowest Animal in the World If you want to know the record holder for the slowest animal in the world, then you're in the right place. There are 3 animals known to be the slowest animals in the world. Sloths move only when necessary and even then very slowly. On the ground the maximum speed of the three-toed sloth is 2 m or 6.5 feet per minute or 0.15 mile per hour. A garden snail's speed is 0.03 mph (yes a snail is an animal and not an insect). Due to its slowness, the snail has traditionally been seen as a symbol of laziness. In Judeo-Christian culture, it has often been viewed as a manifestation of the deadly sin of sloth. A giant tortoise's speed is 0.17 miles per hour. Check also here the smallest animal or the smallest fish . For a list of the most extreme known achievements in the planet, check our top world records . Other Related World Records

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In which part of the atmosphere is the ozone layer?

  The Ozone Layer The ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone (O3). This layer absorbs 97-99% of the sun's high frequency ultraviolet light, which is potentially damaging to life on earth. Over 90% of ozone in earth's atmosphere is present here "Relatively high" means a few parts per million—much higher than the concentrations in the lower atmosphere but still small compared to the main components of the atmosphere. It is mainly located in the lower portion of the stratosphere from approximately 15 km to 35 km above Earth's surface, though the thickness varies seasonally and geographically. A dobson unit is the most basic measure used in ozone research.One Dobson Unit (DU) is defined to be 0.01 mm thickness at STP (standard temperature and pressure). Ozone layer thickness is expressed in terms of Dobson units, which measure what its physical thickness would be if compressed in the Earth's atmosphere. In those terms, it's very thin indeed. A normal range is 300 to 500 Dobson units, which translates to an eighth of an inch-basically two stacked pennies.      In space, it's best not to envision the ozone layer as a distinct, measurable band. Instead, think of it in terms of parts per million concentrations in the stratosphere (the layer six to 30 miles above the Earth's surface). The unit is named after G.M.B. Dobson, one of the first scientists to investigate atmospheric ozone . A thinning ozone layer leads to a number of serious health risks for humans. It causes greater incidences of skin cancer and cataract of the eye, with children being particularly vulnerable. There are also serious impacts for biodiversity. Increased UV-B rays reduce levels of plankton in the oceans and subsequently diminish fish stocks. It can also have adverse effects on plant growth, thus reducing agricultural productivity. Another negative effect is the reduced lifespan of certain materials. Severe depletion of the Antarctic ozone layer was first observed in the early 1980s. The international response embodied in the Montreal Protocol. Today 191 countries worldwide have signed the Montreal Protocol which is widely regarded as the most successful Multinational Environmental Agreement ever reached to date. Furthermore the phasing out of ozone depleting substances (ODS) has helped to fight climate change since many ODS are also powerful greenhouse gases.  

Stratosphere

Which Indian state is at the eastern end of the Himalayas?

Basic Ozone Layer Science | Ozone Layer Protection | US EPA Basic Ozone Layer Science I. The Ozone Layer The Earth's atmosphere is composed of several layers. The lowest layer, the troposphere Addressing Ozone Layer Depletion Most atmospheric ozone is concentrated in a layer in the stratosphere, about 9 to 18 miles (15 to 30 km) above the Earth's surface (see the figure below). Ozone is a molecule that contains three oxygen atoms. At any given time, ozone molecules are constantly formed and destroyed in the stratosphere. The total amount has remained relatively stable during the decades that it has been measured. UVBA band of ultraviolet radiation with wavelengths from 280-320 nanometers produced by the Sun. UVB is a kind of ultraviolet light from the sun (and sun lamps) that has several harmful effects. UVB is particularly effective at damaging DNA. It is a cause of melanoma and other types of skin cancer. It has also been linked to damage to some materials, crops, and marine organisms. The ozone layer protects the Earth against most UVB coming from the sun. It is always important to protect oneself against UVB, even in the absence of ozone depletion, by wearing hats, sunglasses, and sunscreen. However, these precautions will become more important as ozone depletion worsens. NASA provides more information on their web site (http://www.nas.nasa.gov/About/Education/Ozone/radiation.html). . UVB has been linked to many harmful effects , including skin cancers, cataracts, and harm to some crops and marine life. Scientists have established records spanning several decades that detail normal ozone levels during natural cycles. Ozone concentrations in the atmosphere vary naturally with sunspots, seasons, and latitude. These processes are well understood and predictable. Each natural reduction in ozone levels has been followed by a recovery. Beginning in the 1970s, however, scientific evidence showed that the ozone shield was being depleted well beyond natural processes. Additional Information Health and Environmental Effects of Ozone Depletion II. Ozone Depletion When chlorine and bromine atoms come into contact with ozone in the stratosphere, they destroy ozone molecules. One chlorine atom can destroy over 100,000 ozone molecules before it is removed from the stratosphere. Ozone can be destroyed more quickly than it is naturally created. Some compounds release chlorine or bromine when they are exposed to intense UV light in the stratosphere. These compounds contribute to ozone depletion, and are called ozone-depleting substances ( ODS methyl bromideA compound consisting of carbon, hydrogen, and bromine. Methyl Bromide is an effective pesticide used to fumigate soil and many agricultural products. Because it contains bromine, it depletes stratospheric ozone and has an ozone depletion potential of 0.6. Production of methyl bromide was phased out on December 31, 2004, except for allowable exemptions. Much more information is available (http://www.epa.gov/ozone/mbr/index.html). . Although ODS are emitted at the Earth’s surface, they are eventually carried into the stratosphere in a process that can take as long as two to five years. In the 1970s, concerns about the effects of ozone-depleting substances ( ODS

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What is the name of the atmospheric gas which screens out the sun's harmful ultraviolet radiation?

Ultraviolet Radiation: How It Affects Life on Earth : Feature Articles   By Jeannie Allen · September 6, 2001 The sun radiates energy in a wide range of wavelengths, most of which are invisible to human eyes. The shorter the wavelength, the more energetic the radiation, and the greater the potential for harm. Ultraviolet (UV) radiation that reaches the Earth’s surface is in wavelengths between 290 and 400 nm (nanometers, or billionths of a meter). This is shorter than wavelengths of visible light, which are 400 to 700 nm. People and plants live with both helpful and harmful effects of ultraviolet (UV) radiation from the sun. (Photograph courtesy Jeannie Allen) UV radiation from the sun has always played important roles in our environment, and affects nearly all living organisms. Biological actions of many kinds have evolved to deal with it. Yet UV radiation at different wavelengths differs in its effects, and we have to live with the harmful effects as well as the helpful ones. Radiation at the longer UV wavelengths of 320-400 nm, called UV-A, plays a helpful and essential role in formation of Vitamin D by the skin, and plays a harmful role in that it causes sunburn on human skin and cataracts in our eyes. The incoming radiation at shorter wavelengths, 290-320 nm, falls within the UV-B part of the electromagnetic spectrum. (UV-B includes light with wavelengths down to 280 nm, but little to no radiation below 290 nm reaches the Earth’s surface). UV-B causes damage at the molecular level to the fundamental building block of life— deoxyribonucleic acid (DNA). Electromagnetic radiation exists in a range of wavelengths, which are delineated into major divisions for our convenience. Ultraviolet B radiation, harmful to living organisms, represents a small portion of the spectrum, from 290 to 320 nanometer wavelengths. (Illustration by Robert Simmon) DNA readily absorbs UV-B radiation, which commonly changes the shape of the molecule in one of several ways. The illustration below illustrates one such change in shape due to exposure to UV-B radiation. Changes in the DNA molecule often mean that protein-building enzymes cannot “read” the DNA code at that point on the molecule. As a result, distorted proteins can be made, or cells can die. Ultraviolet (UV) photons harm the DNA molecules of living organisms in different ways. In one common damage event, adjacent bases bond with each other, instead of across the “ladder.” This makes a bulge, and the distorted DNA molecule does not function properly. (Illustration by David Herring) But living cells are “smart.” Over millions of years of evolving in the presence of UV-B radiation, cells have developed the ability to repair DNA. A special enzyme arrives at the damage site, removes the damaged section of DNA, and replaces it with the proper components (based on information elsewhere on the DNA molecule). This makes DNA somewhat resilient to damage by UV-B. In addition to their own resiliency, living things and the cells they are made of are protected from excessive amounts of UV radiation by a chemical called ozone. A layer of ozone in the upper atmosphere absorbs UV radiation and prevents most of it from reaching the Earth. Yet since the mid-1970s, human activities have been changing the chemistry of the atmosphere in a way that reduces the amount of ozone in the stratosphere (the layer of atmosphere ranging from about 11 to 50 km in altitude). This means that more ultraviolet radiation can pass through the atmosphere to the Earth’s surface, particularly at the poles and nearby regions during certain times of the year. Without the layer of ozone in the stratosphere to protect us from excessive amounts of UV-B radiation, life as we know it would not exist. Scientific concern over ozone depletion in the upper atmosphere has prompted extensive efforts to assess the potential damage to life on Earth due to increased levels of UV-B radiation. Some effects have been studied, but much remains to be learned.

Ozone

What is the world's deepest ocean?

Harmful radiation harmful radiation ECO-PROS Third from the Sun Coral reefs are being damaged and dying from harmful human activities. The deteriorating condition of coral reefs is causing great environmental concern. Protection ... a very thin layer of atmosphere provides our life support system and protects us from harmful radiation. Approximately 110,000 million tons of carbon dioxide is released into the atmosphere each ... www.eco-pros.com ECO-PROS - Nature Knows Best To provide a blanket of warmth around the planet The atmosphere is being damaged by carbon dioxide overload, so more harmful radiation is reaching us ... AIR, WATERS AND SOIL CLEAR-CUTTING FORESTS DUMPING TOXIC WASTE CUTTING OLD-GROWTH TREES HARMFUL FISHING METHODS DEPLETING AND WASTING NATURAL RESOURCES DESTRUCTION OF OZONE LAYER DESTRUCTION OF BIOLOGICAL ... (UV) rays from the sun, protecting the Earth from this harmful radiation. But down here in the troposphere, where we all live and breathe, ozone turns from ... www.otcair.org The Montreal Protocol ... EPA Earth's sunscreen - the ozone layer The ozone layer screens out the sun’s harmful ultraviolet radiation. Can we reverse its destruction? Information from the Australian Academy of Science's NOVA ... www.dar.csiro.au National Geographic: Sunken Nuclear Subs -- Radiation Risk? National Geographic: Sunken Nuclear Subs -- Radiation Risk? Do sunken reactors threaten human and marine life? Radioactive nuclear reactors are resting around ... ) to 985 feet (300 meters). While this would seem dire, experts say the chances of harmful radiation leaks are slim. In addition to thick metal shielding around the U.S. reactors, the ... nationalgeographic.com Nuclear Energy Agency Press Kits - Radiation protection Over the middle decades of this century, it was gradually recognised that there were other, less obvious, harmful radiation effects such as radiation-induced cancer, for which there is a certain risk even at low doses of radiation. This risk cannot be completely prevented ... nea.fr www.RadiationFree.com- Cellular Phone Radiation Shields & WIreless Phone Radiation Protection Devices. Cellular Phone Radiation Shields & WIreless Phone Radiation Protection Devices. ....Internet Special!!!....New 2- Piece Cell Phone Radiation Shields 60% Off!!! Time-Limited Special Price, Only $14.95 Each!!!....Free ... Only $14.95 Each! Free Shipping When Ordering Two or More Radiation Shields! Prevents up to 99% of All Harmful Waves From Entering Through Your Ear Works With All Phones and ... rpmwebworx.com Earth. UV-B radiation leads to changes, some of them harmful, in the chemical structure of the DNA of living cells. Atmospheric ozone reduces the UV-B radiation from the Sun in ... fmi.fi On this page: General Information Understanding Radiation ... epa.gov

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Which is the largest animal ever to have inhabited the Earth?

What is the biggest animal ever to exist on Earth? | HowStuffWorks What is the biggest animal ever to exist on Earth? Sebastien Burel/ Dreamstime.com By considerable measure, the largest known animal on Earth is the blue whale . Mature blue whales can measure anywhere from 75 feet (23 m) to 100 feet (30.5 m) from head to tail, and can weigh as much as 150 tons (136 metric tons). That's as long as an 8- to 10-story building and as heavy as about 112 adult male giraffes! These days, most adult blue whales are only 75 to 80 feet long; whalers hunted down most of the super giants. Female blue whales generally weigh more than the males. The largest blue whale to date is a female that weighed 389,760 pounds (176,792 kg). A blue whale's head is so wide that an entire professional football team -- about 50 people -- could stand on its tongue. Its heart is as big as a small car , and its arteries are wide enough that you could climb through them. Even baby blue whales dwarf most animals. At birth, a blue whale calf is about 25 feet (7.6 m) long and weighs more than an elephant. And they do grow up fast: During the first 7 months of its life, a blue whale drinks approximately 100 gallons (379 liters) of its mother's milk per day, putting on as much as 200 pounds (91 kg) every 24 hours. An adult blue whale can eat more than 4 tons (3.6 metric tons) of krill, a tiny shrimp-like creature, every day. A Whale of a World Marine Mammal Quiz This puts blue whales well above any known land mammal in terms of size. Most people believe that the largest animals to ever exist on Earth were the dinosaurs . However, one of the largest land dinosaurs, the sauropod Argentinosaurus, weighed only about 180,000 pounds (81,647 kg). That's little more than half the size of an adult blue whale. It makes a lot of sense that the world's largest animal would be a sea creature. Land animals have to support their own weight, whereas sea creatures get some help from the water. It is believed that at one time there were more than 200,000 blue whales. There are only about 10,000 blue whales now -- they've been on the endangered list since the mid-1960s -- and the population is not expected to recover. ­

Blue whale

What once covered 14% of the Earth's land area, but by 1991 over half had been destroyed?

15 of the Largest Animals in the World «TwistedSifter     The blue whale (Balaenoptera musculus) is a marine mammal belonging to the suborder of baleen whales. At 30 metres (98 ft) in length and 180 metric tons (200 short tons) or more in weight, it is the largest known animal to have ever existed. The Blue Whale’s tongue weighs around 2.7 metric tons (5,952 pounds), about the size of an average Asian Elephant and its heart weighs about 600 kg (1,300 lb) and is the largest known in any animal. Not only is the heart similar size to a mini-cooper car but also comparable in weight.   The Blue Whale is thought to feed almost exclusively on small, shrimp-like creatures called Krill. During the summer feeding season the Blue Whale gorges itself, consuming an astounding 3.6 metric tons (7,900 pounds) or more each day. This means it may eat up to 40 million krill a day with a daily calorie requirement of an adult Blue Whale in the region of 1.5 million. [ Source ]   The Heaviest Land Animal in the World: The African Bush Elephant     The African Bush Elephant is the largest living terrestrial (land) animal, with males reaching 6 to 7.5 metres (19.7 to 24.6 ft) in length, 3.3 metres (10.8 ft) in height at the shoulder, and weighing 6 t (13,000 lb). Females are much smaller, reaching 5.4 to 6.9 metres (17.7 to 22.6 ft) in length, 2.7 metres (8.9 ft) in height at the shoulder, and weighing 3 t (6,600 lb). The adult African bush elephant generally has no natural predators due to its great size, but the calves (especially the newborn) are vulnerable to lion and crocodile attacks, and (rarely) to leopard and hyena attacks. [ Source ]   The Tallest Land Animal in the World: The Giraffe   Photograph by Luca Galuzzi – www.galuzzi.it   The giraffe (Giraffa camelopardalis) is an African even-toed ungulate mammal and the tallest living terrestrial animal in the world. It stands 5–6 m (16–20 ft) tall and has an average weight of 1,600 kg (3,500 lb) for males and 830 kg (1,800 lb) for females. The giraffe has an extremely elongated neck, which can be over 2 m (6 ft 7 in) in length, accounting for nearly half of the animal’s vertical height. The long neck results from a disproportionate lengthening of the cervical vertebrae, not from the addition of more vertebrae. [ Source ]   The Largest Carnivora in the World: The Southern Elephant Seal   Photograph by DAVID SHACKELFORD   The Southern elephant seal is the largest carnivore living today. This seals’ size shows extreme sexual dimorphism, possibly the largest of any mammal, with the males typically five to six times heavier than the females. While the females average 400 to 900 kilograms (880 to 2,000 lb) and 2.6 to 3 meters (8.5 to 9.8 ft) long, the bulls average 2,200 to 4,000 kilograms (4,900 to 8,800 lb) and 4.5 to 5.8 meters (15 to 19 ft) long. The record-sized bull, shot in Possession Bay, South Georgia on February 28, 1913, measured 6.85 meters (22.5 ft) long and was estimated to weigh 5,000 kilograms (11,000 lb).   Southern elephant seals dive repeatedly, each time for more than twenty minutes, to hunt their prey—squid and fish— at depths of 400 to 1,000 meters (1,300 to 3,300 ft). The documented diving records for the seals are nearly two hours for the duration, and more than 1,400 meters (4,600 ft) in depth. [ Source ]   The diverse order Carnivora includes over 280 species of placental mammals. Its members are formally referred to as carnivorans, while the word “carnivore” (often popularly applied to members of this group) can refer to any meat-eating organism. Carnivorans are the most diverse in size of any mammalian order, ranging from the least weasel (Mustela nivalis), at as little as 25 grams (0.88 oz) and 11 centimetres (4.3 in), to the polar bear and southern elephant seal. [ Source ]   The Largest Reptile in the World: The Saltwater Crocodile     The saltwater crocodile (Crocodylus porosus), is the largest of all living reptiles. It is found in suitable habitats from Northern Australia through Southeast Asia to the eastern coast of India. An adult male saltwater crocodile’s weight is 409 to 1,000 kilograms (900–2,200 lb) and length is normally 4.1 to 5.5 metres (13–18 ft). However, mature males can exceed 6 metres (20 ft) and weigh more than 1,000 kilograms (2,200 lb) and this species is the only extant crocodilian to regularly reach or exceed 4.8 metres (16 ft). The saltwater crocodile is an opportunistic apex predator capable of taking nearly any animal that enters its territory, either in the water or on dry land. [ Source ]   The Largest Bats in the World: The Giant golden-crowned flying fox   Golden Crowned Flying Fox | Photograph by Latorilla   Spectacled Flying Fox | Photograph by Mnolf   The largest bat species is the Giant golden-crowned flying fox (Acerodon jubatus), an endangered fruit bat from the rainforests of the Philippines that is part of the megabat family. The maximum size is believed to approach 1.5 kg (3.3 lb), 55 cm (22 in) long, and the wingspan may be almost 1.8 m (5.9 ft). The Large Flying Fox (Pteropus vampyrus) is smaller in body mass and length, but it has been known to exceed the Golden-crowned species in wingspan. Specimens have been verified to 1.83 m (6.0 ft) and possibly up to 2 m (6.6 ft) in wingspan. [ Source ]   Photograph by Library of Congress   Osteichthyes, also called bony fish, are a taxonomic group of fish that have bony, as opposed to cartilaginous, skeletons. The vast majority of fish are osteichthyes, which is an extremely diverse and abundant group consisting of over 29,000 species. It is the largest class of vertebrates in existence today.   The largest living bony fish is the widely distributed ocean sunfish (Mola mola). It resembles a fish head with a tail, and its main body is flattened laterally. The mature ocean sunfish has an average length of 1.8 m (5.9 ft), a fin-to-fin length of 2.5 m (8.2 ft) and an average weight of 1,000 kg (2,200 lb), although individuals up to 3.3 m (10.8 ft) in length 4.2 m (14 ft) across the fins and weighing up to 2,300 kg (5,100 lb) have been observed. [ Source ]   The Heaviest Flying Bird in the World: The Dalmatian Pelican   Photograph by Doug Janson   The Dalmatian Pelican (Pelecanus crispus) is a member of the pelican family. It breeds from southeastern Europe to India and China in swamps and shallow lakes. This is the largest of the pelicans, averaging 160–180 cm (63-70 inches) in length, 11–15 kg (24-33 lbs) in weight and just over 3 m (10 ft) in wingspan. With a mean weight of 11.5 kg (25 lb), it is the world’s heaviest flying bird species on average, although large male bustards and swans can exceed the pelican in maximum weight. [ Source ]  

i don't know

Which inland sea between Kazakhstan and Uzbekistan is fast disappearing because the rivers that feed it have been diverted and dammed?

Effective Communication at Pepsi Co - Term Paper Effective Communication at Pepsi Co Which Indian state is at the eastern end of the Himalayas? A: Assam. What is the name of the atmospheric gas which screens out the sun's harmful ultraviolet radiation? A: Ozone. What is the world's deepest ocean? A: Pacific. Which is the largest animal ever to have inhabited the Earth? A: Blue Whale. What once covered 14% of the Earth's land area, but by 1991 over half had been destroyed? A: Rainforest. Which inland sea between Kazakhstan and Uzbekistan is fast disappearing because the rivers that feed it have been diverted and dammed? A: Aral Sea. The damaged Chernobyl nuclear power station is situated in which country? A: Ukraine. What type of rock is granite? A: Igneous. What type of rock is basalt? A: Igneous. What is the main constituent of natural gas? A: Methane. What is the term for nutrient enrichment of lakes? A: Eutrophication. Which of the Earth's atmospheric layers reflects radio waves? A: Ionosphere. Which gas forms 80% of Earth's atmosphere? A: Nitrogen. In which mountain chain would you find Mount Everest? A: Himalayas. What is the collective term for substances such as coal, oil and natural gas, the burning of which produces carbon dioxide? A: Fossil fuel. What contributes to the greenhouse effect at lower atmospheric levels, but in the upper atmosphere protects life on Earth? A: Ozone. What is the name of the process by which substances are washed out of the soil? A: Leaching. Who was director of the environmental pressure group Friends of the Earth 1984 - 90? A: Jonathon Porritt. Which European country is committed to decommissioning all of its nuclear reactors? A: Sweden. Which Canadian city gave its name to the 1987world agreement on protection of the ozone layer? A: Montreal. Five-legged creatures have damaged which 1250 mile long wonder of the world? A: Great Barrier Reef.

Aral Sea

The damaged Chernobyl nuclear power station is situated in which country?

The growing desertification – global climate change and its causes – Sandstorms | Cricketdiane's Weblog The growing desertification – global climate change and its causes – Sandstorms ≈ 1 Comment Tags NASA Satellites Unlock Secret to Northern India’s Vanishing Water August 12, 2009 WASHINGTON — Using NASA satellite data, scientists have found that groundwater levels in northern India have been declining by as much as one foot per year over the past decade. Researchers concluded the loss is almost entirely due to human activity. More than 26 cubic miles of groundwater disappeared from aquifers in areas of Haryana, Punjab, Rajasthan and the nation’s capitol territory of Delhi, between 2002 and 2008. This is enough water to fill Lake Mead, the largest manmade reservoir in the United States, three times. A team of hydrologists led by Matt Rodell of NASA’s Goddard Space Flight Center in Greenbelt, Md., found that northern India’s underground water supply is being pumped and consumed by human activities, such as irrigating cropland, and is draining aquifers faster than natural processes can replenish them. The results of this research were published today in Nature. The finding is based on data from NASA’s Gravity Recovery and Climate Experiment (GRACE), a pair of satellites that sense changes in Earth’s gravity field and associated mass distribution, including water masses stored above or below Earth’s surface. As the twin satellites orbit 300 miles above Earth’s surface, their positions change relative to each other in response to variations in the pull of gravity. Changes in underground water masses affect gravity enough to provide a signal that can be measured by the GRACE spacecraft. After accounting for other mass variations, such changes in gravity are translated into an equivalent change in water. “Using GRACE satellite observations, we can observe and monitor water storage changes in critical areas of the world, from one month to the next, without leaving our desks,” said study co-author Isabella Velicogna of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., and the University of California, Irvine. Groundwater comes from the natural percolation of precipitation and other surface waters down through Earth’s soil and rock, accumulating in cavities and layers of porous rock, gravel, sand or clay. Groundwater levels respond slowly to changes in weather and can take months or years to replenish once pumped for irrigation or other uses. Data provided by India’s Ministry of Water Resources to the NASA-funded researchers suggested groundwater use across India was exceeding natural replenishment, but the regional rate of depletion was unknown. Rodell and colleagues analyzed six years of monthly GRACE data for northern India to produce a time series of water storage changes beneath the land surface. “We don’t know the absolute volume of water in the northern Indian aquifers, but GRACE provides strong evidence that current rates of water extraction are not sustainable,” said Rodell. “The region has become dependent on irrigation to maximize agricultural productivity. If measures are not taken to ensure sustainable groundwater usage, the consequences for the 114 million residents of the region may include a collapse of agricultural output and severe shortages of potable water.” Researchers examined data and models of soil moisture, lake and reservoir storage, vegetation and glaciers in the nearby Himalayas in order to confirm that the apparent groundwater trend was real. The loss is particularly alarming because it occurred when there were no unusual trends in rainfall. In fact, rainfall was slightly above normal for the period. The only influence they couldn’t rule out was human. “For the first time, we can observe water use on land with no additional ground-based data collection,” said co-author James Famiglietti of the University of California, Irvine. “This is critical because in many developing countries, where hydrological data are both sparse and hard to access, space-based methods provide perhaps the only opportunity to assess changes in fresh water availability across large regions.” GRACE is a partnership between NASA and the German Aerospace Center, DLR. The University of Texas Center for Space Research in Austin has overall GRACE mission responsibility. GRACE was launched in 2002. For more information, please visit: http://www.nasa.gov/topics/earth/features/india_water.html For more information about NASA and agency programs, visit: ** DESERT LANDFORMS Looking at a satellite image of the whole earth it is easy to spot a series of conspicuous ochre, vegetation-barren areas that run parallel to the equator, in both the northern and southern hemispheres, along two East-West fringes at i5-35° latitude (Figure 1.1). They are the mid-latitude deserts of the world, lying some 2 000-4 000 km away from the equatorial rainforests. In the northern hemisphere, the succession of mid-latitude subtropical deserts is formed by (1) the Mojave, Sonoran, and Chihuahuan Deserts in North America, (i) the Sahara’s immense swathe in Northern Africa and the Somali-Ethiopian deserts in the Horn of Africa, and (3) the deserts of Asia, including the Arabian, Mesopotamian, Persian, and Thar deserts that stretch from West Asia into Pakistan and India, as well as the Central Asian deserts in Uzbekistan, Turkmenistan, and the Taklimakan and Gobi deserts in China and Mongolia. In the southern hemisphere, the chain is formed by (1) the Atacama, Puna, and Monte Deserts in South America, (i) the Namib and the Karoo in southern Africa, and (3) the vast expanse of the Australian deserts (Allan and others 1993, McGinnies and others 1977, Pipes 1998, Ricciuti 1996). There are many criteria to define a desert but perhaps the most important one is aridity — the lack of water as the main factor limiting biological processes. One of the most common approaches to measure aridity is through an estimator called the Aridity Index, which is simply the ratio between mean annual precipitation (P) and mean annual potential evapotranspiration (PET, the amount of water that would be lost from water-saturated soil by plant transpiration and direct evaporation from the ground; Thornthwaite 1948). Arid and hyperarid regions have a P/PET ratio of less than 0.i0; that is, rainfall supplies less than i0 per cent of the amount of water needed to support optimum plant growth (UNEP 1997, FAO 2004). Aridity is highest in the Saharan and Chilean-Peruvian deserts, followed by the Arabian, East African, Gobi, Australian, and South African Deserts, and it is generally lower in the Thar and North American deserts. Although the aridity indices vary in the different deserts in the world, all of them fall within the arid and hyperarid categories (Table 1.1). fig1.1.jpg Kumtor Gold Mine From Wikipedia, the free encyclopedia Kumtor Gold Mine is an open-pit gold mining site in Issyk Kul Province of Kyrgyzstan located about 350 km (220 mi) southeast of the capital Bishkek and 80 km (50 mi) south of Lake Issyk-Kul near the border with China. Kumtor is 100% owned by the Canadian mining company, Centerra Gold, through its wholly owned subsidiary, Kumtor Gold Company. The mine started operation in Q2 1997 and produced more than 5.8 million ounces (180,000 kg) of gold through the end of 2006. Located in Tian Shan mountains at more than 4,000 m (14,000 ft) above sea level, Kumtor is the second-highest gold mining operation in the world after Yanacocha gold mine in Peru. The mine was linked to a major environmental incident in 1998 when a truck carrying 1762 kg of sodium cyanide (a chemical used to dissolve gold from granulated ore the use of which is highly controversial) fell into the Barskaun River on the way to Kumtor. External links * Centerra Gold – Kumtor Gold Mine web page Coordinates: 41°52?N 78°12?E? / ?41.867°N 78.2°E? / 41.867; 78.2 Retrieved from http://en.wikipedia.org/wiki/Kumtor_Gold_Mine Categories: Geography of Kyrgyzstan | Economy of Kyrgyzstan | Gold mines in Kyrgyzstan | Issyk Kul Province | Economy of the Soviet Union | Surface mines in Kyrgyzstan Uranium Mining Kazakstan - Kazatomprom 2005 - 2010 *** The Central Asian countries, Kazakhstan, Kyrgyzstan, Mongolia, Tajikistan, Turkmenistan, and Uzbekistan, are also affected. More than 80% of Afghanistan’s and Pakistan’s land could be subject to soil erosion and desertification.[10] In Kazakhstan, nearly half of the cropland has been abandoned since 1980. In Iran, sand storms were said to have buried 124 villages in Sistan and Baluchestan Province in 2002, and they had to be abandoned. In Latin America, Mexico and Brazil are affected by desertification.[11] Globally, desertification claims a Nebraska-sized area of productive capacity each year.[2] It is principally caused by overgrazing, overdrafting of groundwater and diversion of water from rivers for human consumption and industrial use, all of these processes fundamentally driven by overpopulation. From Wikipedia, the free encyclopedia Ship stranded by the retreat of the Aral Sea Goat husbandry is common through the Norte Chico of Chile, however it produces severe erosion and desertification. Image from upper Limarí River Desertification is the degradation of land in arid and dry sub-humid areas, resulting primarily from man-made activities and influenced by climatic variations. It is principally caused by overgrazing, overdrafting of groundwater and diversion of water from rivers for human consumption and industrial use, all of these processes fundamentally driven by overpopulation. A major impact of desertification is biodiversity loss and loss of productive capacity, for example, by transition from land dominated by shrublands to non-native grasslands. In the semi-arid regions of southern California, many coastal sage scrub and chaparral ecosystems have been replaced by non-native, invasive grasses due to the shortening of fire return intervals. This can create a monoculture of annual grass that cannot support the wide range of animals once found in the original ecosystem. In Madagascar’s central highland plateau, 10% of the entire country has been lost to desertification due to slash and burn agriculture by indigenous peoples. In Africa, if current trends of soil degradation continue, the continent will be able to feed only 25% of its population by 2025, according to UNU’s Ghana-based Institute for Natural Resources in Africa.[1] Globally, desertification claims a Nebraska-sized area of productive capacity each year.[2] Causes Sand dunes advancing on Nouakchott, the capital of Mauritania. Desertification is induced by several factors, primarily anthropogenic causes, which began in the Holocene era and continue at the highest pace today. The primary reasons for desertification are overgrazing, over-cultivation, increased fire frequency, water impoundment, deforestation, overdrafting of groundwater, increased soil salinity, and global climate change.[3] Deserts may be separated from surrounding, less arid areas by mountains and other contrasting landforms that reflect fundamental structural differences in the terrain. In other areas, desert fringes form a gradual transition from a dry to a more humid environment, making it more subtle to determine the desert border. These transition zones can have fragile, delicately balanced ecosystems. Desert fringes often are a mosaic of microclimates. Small pieces of wood support vegetation that picks up heat from the hot winds and protects the land from the prevailing winds. After rainfall the vegetated areas are distinctly cooler than the surroundings. In these marginal areas activity centres may stress the ecosystem beyond its tolerance limit, resulting in degradation of the land. By pounding the soil with their hooves, livestock compact the substrate, increase the proportion of fine material, and reduce the percolation rate of the soil, thus encouraging erosion by wind and water. Grazing and collection of firewood reduce or eliminate plants that bind the soil and prevent erosion. All these come about due to the trend towards settling in one area instead of a nomadic culture. Sand dunes can encroach on human habitats. Sand dunes move through a few different means, all of them assisted by wind. One way that dunes can move is through saltation, where sand particles skip along the ground like a rock thrown across a pond might skip across the water’s surface. When these skipping particles land, they may knock into other particles and cause them to skip as well. With slightly stronger winds, particles collide in mid-air, causing sheet flows. In a major dust storm, dunes may move tens of meters through such sheet flows. And like snow, sand avalanches, falling down the steep slopes of the dunes that face away from the winds, also moving the dunes forward. It is a common misconception that droughts by themselves cause desertification. While drought is a contributing factor, the root causes are all related to man’s overexploitation of the environment.[3] Droughts are common in arid and semiarid lands, and well-managed lands can recover from drought when the rains return. Continued land abuse during droughts, however, increases land degradation. Increased population and livestock pressure on marginal lands has accelerated desertification. In some areas, nomads moving to less arid areas disrupt the local ecosystem and increase the rate of erosion of the land. Nomads typically try to escape the desert, but because of their land-use practices, they are bringing the desert with them. Some arid and semi-arid lands can support crops, but additional pressure from greater populations or decreases in rainfall can lead to the few plants present disappearing. The soil becomes exposed to wind, causing soil particles to be deposited elsewhere. The top layer becomes eroded. With the removal of shade, rates of evaporation increase and salts become drawn up to the surface. This increases soil salinity which inhibits plant growth. The loss of plants causes less moisture to be retained in the area, which may change the climate pattern leading to lower rainfall. This degradation of formerly productive land is a complex process. It involves multiple causes, and it proceeds at varying rates in different climates. Desertification may intensify a general climatic trend toward greater aridity, or it may initiate a change in local climate. Desertification does not occur in linear, easily mappable patterns. Deserts advance erratically, forming patches on their borders. Areas far from natural deserts can degrade quickly to barren soil, rock, or sand through poor land management. The presence of a nearby desert has no direct relationship to desertification. Unfortunately, an area undergoing desertification is brought to public attention only after the process is well under way. Often little data are available to indicate the previous state of the ecosystem or the rate of degradation. Desertification is both an environmental and developmental problem. It affects local environments and populations’ ways of life. Its effects, however, have more global ramifications concerning biodiversity, climatic change and water resources. The degradation of terrain is directly linked to human activity and constitutes both one of the consequences of poor development and a major obstacle to the sustainable development of dryland zones.[4] Combating desertification is complex and difficult, usually impossible without alteration of land management practises that led to the desertification. Over-exploitation of the land and climate variations can have identical impacts and be connected in feedbacks, which makes it very difficult to choose the right mitigation strategy. Investigating the historic desertification plays a special role since it allows better distinguishing of human and natural factors. In this context, recent research about historic desertification in Jordan questions the dominant role of man. It seems possible that current measures like reforestation projects cannot achieve their goals if global warming continues. Forests may die when it gets drier, and more frequent extreme events as testified in sediments from earlier periods could become a threat for agriculture, water supply, and infrastructure. [etc. – includes a section on prehistoric desertification] Historical and current desertification Overgrazing and to a lesser extent drought in the 1930s transformed parts of the Great Plains in the United States into the  Dust Bowl . During that time, a considerable fraction of the plains population abandoned their homes to escape the unproductive lands. Improved agricultural and water management have prevented a disaster of the earlier magnitude from recurring, but desertification presently affects tens of millions of people with primary occurrence in the lesser developed countries. Lake Chad in a 2001 satellite image, with the actual lake in blue. The lake has shrunk by 95% since the 1960s.[5] Desertification is widespread in many areas of the People’s Republic of China. The populations of rural areas have increased since 1949 for economical reasons as more people have settled there. While there has been an increase in livestock, the land available for grazing has decreased. Also the importing of European cattle such as Friesian and Simmental, which have higher food intakes, has made things worse.[citation needed] Human overpopulation is leading to destruction of tropical wet forests and tropical dry forests, due to widening practices of slash-and-burn and other methods of subsistence farming necessitated by famines in lesser developed countries.[citation needed] A sequel to the deforestation is typically large scale erosion, loss of soil nutrients and sometimes total desertification. Examples of this extreme outcome can be seen on Madagascar’s central highland plateau, where about seven percent of the country’s total land mass has become barren, sterile land. Overgrazing has made the Rio Puerco Basin of central New Mexico one of the most eroded river basins of the western United States and has increased the high sediment content of the river.[6] Overgrazing is also contributing to desertification in some parts of Chile, Ethiopia, Morocco and other countries. Overgrazing is also an issue with some regions of South Africa such as the Waterberg Massif, although restoration of native habitat and game has been pursued vigorously since about 1980. Another example of desertification occurring is in the Sahel. The chief cause of desertification in the Sahel is slash-and-burn farming practised by an expanding human population.[7] The Sahara is expanding south at a rate of up to 48 kilometres per year.[8] Ghana[9] and Nigeria currently experience desertification; in the latter, desertification overtakes about 1,355 square miles (3,510 km2) of land per year. The Central Asian countries, Kazakhstan, Kyrgyzstan, Mongolia, Tajikistan, Turkmenistan, and Uzbekistan, are also affected. More than 80% of Afghanistan’s and Pakistan’s land could be subject to soil erosion and desertification.[10] In Kazakhstan, nearly half of the cropland has been abandoned since 1980. In Iran, sand storms were said to have buried 124 villages in Sistan and Baluchestan Province in 2002, and they had to be abandoned. In Latin America, Mexico and Brazil are affected by desertification.[11] Countering desertification Trees are planted instead of sand fences to reduce sand accumulating in a UAE highway. Desertification has been recognized as a major threat to biodiversity. Numerous countries have developed Biodiversity Action Plans to counter its effects, particularly in relation to the protection of endangered flora and fauna.[12][13] A number of methods have been tried in order to reduce the rate of desertification and regain lost land; however, most measures treat symptoms of sand movement and do not address the root causes of land modification such as overgrazing, unsustainable farming (eg cattle farming) and deforestation. In developing countries under threat of desertification, many local people use trees for firewood and cooking which has increased the problem of land degradation and often even increased their poverty. In order to gain further supplies of fuel the local population add more pressure to the depleted forests; adding to the desertification process. Techniques focus on two aspects: provisioning of water (eg by wells and energy intensive systems involving water pipes or over long distances) and fixating and hyper-fertilising soil. Fixating the soil is often done through the use of shelter belts, woodlots and windbreaks. Windbreaks are made from trees and bushes and are used to reduce soil erosion and evapotranspiration. They were widely encouraged by development agencies from the middle of the 1980s in the Sahel area of Africa. Another approach is the spraying of petroleum or nano clay[14] over semi-arid cropland. This is often done in areas where either petroleum or nano clay is easily and cheaply obtainable (eg Iran). In both cases, the application of the material coats seedlings to prevent moisture loss and stop them being blown away. Some soils (eg clay soils), due to lack of water can become consolidated rather than become too loose (as in the case of sandy soils). Some techniques as zaï or tillage are then used to still allow the planting of crops.[15] The enriching of the soil and the restoration of its fertility is often done by a plants. Of these, the Leguminous plants which extract nitrogen from the air and fixes it in the soil, and food crops/trees as grains, barley, beans and dates are the most important. When housing is foreseen in or near the reforestation area, organic waste material (eg hazelnut shells, bamboo, chicken manure, …) can be made into biochar or Terra preta nova by a pyrolysis unit. This substance may be used to enrich planting spaces for high-demanding crops.[16] Finally, some approaches as stacking stones around the base of trees and artificial groove-digging also help in increasing the chance of local success of crop survival. Stacked stones help to collect morning dew and retain soil moisture. Artificial grooves are dug in the ground as to retain rainfall and trap wind-blown seeds. [17][18] In order to solve the problem of cutting trees for personal energy requirements, solutions as Solar ovens and efficient wood burning cook stoves are being advocated as a means to relieving some of this pressure upon the environment; however, these techniques are generally prohibitively expense in the very regions where they are needed. While desertification has received some publicity by the news media, most people are unaware of the extent of environmental degradation of productive lands and the expansion of deserts. In 1988 Ridley Nelson pointed out that desertification is a subtle and complex process of deterioration. At the local level, individuals and governments can temporarily forestall desertification. Sand fences are used throughout the Middle East and the US, in the same way snow fences are used in the north. Placement of straw grids, each up to a square meter in area, will also decrease the surface wind velocity. Shrubs and trees planted within the grids are protected by the straw until they take root. However, some studies suggest that planting of trees depletes water supplies in the area.[19] In areas where some water is available for irrigation, shrubs planted on the lower one-third of a dune’s windward side will stabilize the dune. This vegetation decreases the wind velocity near the base of the dune and prevents much of the sand from moving. Higher velocity winds at the top of the dune level it off and trees can be planted atop these flattened surfaces. Jojoba plantations, such as those shown, have played a role in combating edge effects of desertification in the Thar Desert, India. Oases and farmlands in windy regions are often protected by the approach described above by planting tree fences or grass belts in order to reduce erosion and walking dunes. Also, small projects as oases often section their plot of land by placing a barrier of thorny bushes or other obstacles to keep grazing animals away from the food crops. Instead, they provide water provisioning (eg from a well, …) outside this barrier. They provide this service mainly to accommodate the animals of travelers (eg camels, …). Sand that manages to pass through the grass belts can be caught in strips of trees planted as wind breaks 50 to 100 meters apart adjacent to the belts. Small plots of trees may also be scattered inside oases to stabilize the area. On a much larger scale, a  Green Wall of China , which will eventually stretch more than 5,700 kilometers in length, nearly as long as the Great Wall of China, is being planted in north-eastern China to protect  sandy lands  – deserts created by human activity. [ . . . ] Africa, with coordination from Senegal, has launched its own  green wall  project[23]. Trees will be planted on a 15 km wide land strip from Senegal to Djibouti. Aside from countering desert progression, the project is also aimed at creating new economic activities, especially thanks to tree products such as gum arabic [24] More efficient use of existing water resources and control of salinization are other tools for mitigating arid lands. New ways are also being sought to find groundwater resources and to develop more effective ways of irrigating arid and semiarid lands. Research on the reclamation of deserts is also focusing on discovering proper crop rotation to protect fragile soil, on understanding how sand-fixing plants can be adapted to local environments, and on how overgrazing can be addressed. A proposal combining desert stabilization and renewable energy is Aerially Delivered Re-forestation and Erosion Control System – [25] Mitigation concepts Sand fences can be used to control drifting of soil and sand and soil erosion. A recent development is the Seawater Greenhouse and Seawater Forest. This proposal is to construct these devices on coastal deserts in order to create freshwater and grow food [26] A similar approach is the Desert Rose concept [27] These approaches are of widespread applicability, since the relative costs of pumping large quantities of seawater inland are low[28]. Another related concept is ADRECS – a system for rapidly delivering soil stabilisation and re forestation techniques coupled with renewable energy generation[29]. Desertification and poverty Numerous authors underline the strong link between desertification and poverty. The proportion of poor people among populations is noticeably higher in dryland zones, especially among rural populations. This situation increases yet further as a function of land degradation because of the reduction in productivity, the precariousness of living conditions and difficulty of access to resources and opportunities.[30] Decision-makers are highly reticent about investing in arid zones with low potential. This absence of investment contributes to the marginalisation of these zones.When unfavourable agro-climatic conditions are combined with an absence of infrastructure and access to markets, as well as poorly-adapted production techniques and an underfed and undereducated population, most such zones are excluded from development.[4] (My Note – just on the other side of the desertification in Northern and Western China – ) Karakol From Wikipedia, the free encyclopedia Karakol is located in Kyrgyzstan Karakol (Kyrgyz), formerly Przhevalsk, is a city of about 75,000, near the eastern tip of Lake Issyk-Kul in Kyrgyzstan, about 150 kilometres (93 mi) from the Kyrgyzstan-China border and 380 kilometres (240 mi) from the capital Bishkek. It is the administrative capital of Issyk Kul Province. To the north, on highway A363, is Tyup and to the southwest Jeti-Ögüz resort. Przhevalsky’s grave, a memorial park and a small museum dedicated to his and other Russian explorations in Central Asia are some 9 kilometres (5.6 mi) north of Karakol at Pristan Przhevalsky, overlooking the Mikhailovka inlet of Lake Issyk-Kul where the former Soviet torpedo testing facilities were located. Facilities themselves are still a closed, military area. Kyrgyzstan From Wikipedia, the free encyclopedia Kyrgyzstan , officially the Kyrgyz Republic, is a country in Central Asia. Landlocked and mountainous, it is bordered by Kazakhstan to the north, Uzbekistan to the west, Tajikistan to the southwest and China to the east. The ethnonym  Kyrgyz , after which the country is named, is thought to originally mean either  forty girls  or  forty tribes , presumably referring to the epic hero Manas who, as legend has it, unified forty tribes against the Khitans. The 40-ray sun on the flag of Kyrgyzstan symbolizes the forty tribes of Manas.[5] [ . . . ] On 3 February 2009, President Kurmanbek Bakiyev announced the imminent closure of the Manas Air Base, the only US military base remaining in Central Asia.[10] The closure was approved by Parliament on 19 February 2009 by 78-1 for the government-backed bill.[11] Kyrgyzstan is among the twenty countries in the world with the highest perceived level of corruption: the 2008 Corruption Perception Index for Kyrgyzstan is 1.8 on a scale of 0 (most corrupt) to 10 (least corrupt).[12] Kyrgyzstan is divided into seven provinces (sing. oblast (???????), pl. oblasttar (?????????)) administered by appointed governors. The capital, Bishkek, and the second large city Osh are administratively independent cities (shaar) with a status equal to a province. Provinces of Kyrgyzstan The provinces, and independent cities, are as follows: 1. Bishkek (city) 8. Issyk-Kul 9. Osh (city) Each province comprises a number of districts (raions), administered by government-appointed officials (akim). Rural communities (ay?l ökmötü), consisting of up to 20 small settlements, have their own elected mayors and councils. Kyrgyzstan is a landlocked country in Central Asia, bordering Kazakhstan, China, Tajikistan and Uzbekistan. The mountainous region of the Tian Shan covers over 80% of the country (Kyrgyzstan is occasionally referred to as  the Switzerland of Central Asia , as a result),[13] with the remainder made up of valleys and basins. Lake Issyk-Kul in the north-western Tian Shan is the largest lake in Kyrgyzstan and the second largest mountain lake in the world after Titicaca. The highest peaks are in the Kakshaal-Too range, forming the Chinese border. Peak Jengish Chokusu, at 7,439 m (24,400 feet), is the highest point and is considered by geologists (though not mountaineers) to be the northernmost peak over 7,000 m (23,000 feet) in the world. Heavy snowfall in winter leads to spring floods which often cause serious damage downstream. The runoff from the mountains is also used for hydro-electricity. The climate varies regionally. The south-western Fergana Valley is subtropical and extremely hot in summer, with temperatures reaching 40°C (104°F.) The northern foothills are temperate and the Tian Shan varies from dry continental to polar climate, depending on elevation. In the coldest areas temperatures are sub-zero for around 40 days in winter, and even some desert areas experience constant snowfall in this period. Kyrgyzstan has significant deposits of metals including gold and rare earth metals. Due to the country’s predominantly mountainous terrain, less than 8% of the land is cultivated, and this is concentrated in the northern lowlands and the fringes of the Fergana Valley. Bishkek in the north is the capital and largest city, with approximately 900,000 inhabitants (as of 2005). The second city is the ancient town of Osh, located in the Fergana Valley near the border with Uzbekistan. The principal river is the Kara Darya, which flows west through the Fergana Valley into Uzbekistan. Across the border in Uzbekistan it meets another major Kyrgyz river, the Naryn. The confluence forms the Syr Darya, which originally flowed into the Aral Sea. At this time it no longer reaches the sea, as its water is withdrawn upstream to irrigate cotton fields in Tajikistan, Uzbekistan, and southern Kazakhstan. The Chu River also briefly flows through Kyrgyzstan before entering Kazakhstan. (see chart toward top of this post about rivers that have been diverted, dammed, are being dammed or almost totally used for irrigation or other human activities, commercial / industrial / mining uses, etc.) Agriculture is an important sector of the economy in Kyrgyzstan (see agriculture in Kyrgyzstan). By the early 1990s, the private agricultural sector provided between one-third and one-half of some harvests. In 2002 agriculture accounted for 35.6% of GDP and about half of employment. Kyrgyzstan’s terrain is mountainous, which accommodates livestock raising, the largest agricultural activity, so the resulting wool, meat and dairy products are major commodities. Main crops include wheat, sugar beets, potatoes, cotton, tobacco, vegetables and fruit. As the prices of imported agrichemicals and petroleum are so high, much farming is being done by hand and by horse, as it was generations ago. Agricultural processing is a key component of the industrial economy as well as one of the most attractive sectors for foreign investment. Kyrgyzstan is rich in mineral resources but has negligible petroleum and natural gas reserves; it imports petroleum and gas. Among its mineral reserves are substantial deposits of coal, gold, uranium, antimony and other valuable metals. Metallurgy is an important industry, and the government hopes to attract foreign investment in this field. The government has actively encouraged foreign involvement in extracting and processing gold. The country’s plentiful water resources and mountainous terrain enable it to produce and export large quantities of hydroelectric energy. The principal exports are nonferrous metals and minerals, woolen goods and other agricultural products, electric energy and certain engineering goods. Imports include petroleum and natural gas, ferrous metals, chemicals, most machinery, wood and paper products, some foods and some construction materials. Its leading trade partners include Germany, Russia, China, Kazakhstan and Uzbekistan. Kyrgyzstan’s population is estimated at 5.2 million in 2007.[16] Of those, 34.4% are under the age of 15 and 6.2% are over the age of 65. The country is rural: only about one-third of Kyrgyzstan’s population live in urban areas. The average population density is 69 people per square mile (29 people per km²). The Kyrgyz have historically been semi-nomadic herders, living in round tents called yurts and tending sheep, horses and yaks. This nomadic tradition continues to function seasonally (see transhumance) as herding families return to the high mountain pasture (or jailoo) in the summer. [etc.] Airports At the end of the Soviet period there were about 50 airports and airstrips in Kyrgyzstan, many of them built primarily to serve military purposes in this border region so close to China. Only a few of them remain in service today. * Manas International Airport near Bishkek is the main international airport, with services to Moscow, Tashkent, Almaty, Beijing, Urumqi, Istanbul, Baku, Delhi and London. * Osh Airport is the main air terminal in the south of the country, with daily connections to Bishkek. * Jalal-Abad Airport is linked to Bishkek by daily flights. The national flag carrier, Kyrgyzstan, operates flights on An-24 aircraft. During the summer months, a weekly flight links Jalal-Abad with the Issyk-Kul Region. * Other facilities built during the Soviet era are either closed down, used only occasionally or restricted to military use (e.g., Kant Air Base near Bishkek, which is used by the Russian Air Force). Waterways Water transport exists only on Lake Issyk Kul, and has drastically shrunk since the end of the Soviet Union. Ports and harbours Balykchy (Ysyk-Kol or Rybach’ye), on Lake Issyk Kul. [and more -] Catchment  area     15,844 square kilometers (6,117.4 sq mi) Basin  countries     Kyrgyzstan Max. length     182 kilometers (113 mi) Max. width     60 kilometers (37 mi) Surface area     6,236 square kilometers (2,407.7 sq mi) Average depth     270 meters (886 ft) Max. depth     668 meters (2,192 ft) Water volume     1,738 km³ (416.97 mi³) Shore  length1     688 kilometers (428 mi) Surface  elevation     1,607 meters (5,272 ft) Settlements     Cholpon-Ata, Karakol 1 Shore length is not a well-defined measure. Issyk Kul (also Ysyk Köl, Issyk-Kol; Kyrgyz: ???? ???, Russian: ?????-????, Chinese: ??) is an endorheic lake in the northern Tian Shan mountains in eastern Kyrgyzstan. It is the tenth largest lake in the world by volume and the second largest saline lake after the Caspian Sea. Although it is surrounded by snow-capped peaks, it never freezes; hence its name, which means  warm lake  in the Kyrgyz language. The lake is a Ramsar site of globally significant biodiversity (Ramsar Site RDB Code 2KG001) and forms part of the Issyk-Kul Biosphere Reserve. It is also the site of an ancient metropolis 2500 years ago, and archaeological excavations are ongoing.[1] Contents Southern shore of lake Issyk Kul Map of Kyrgyzstan showing Issyk Kul in the north Lake Issyk Kul has a length of 182 kilometers (113 mi), a width of up to 60 kilometers (37 mi), and covers an area of 6,236 square kilometers (2,407.7 sq mi). This makes it the second largest mountain lake in the world behind Lake Titicaca in South America. Located at an altitude of 1,607 meters (5,272 ft), it reaches 668 meters (2,192 ft) in depth.[2]. About 118 rivers and streams flow into the lake; the largest are Djyrgalan and Tyup. It is fed by springs, including many hot springs, and snow melt-off. The lake has no current outlet, but some hydrologists hypothesize[3] that, deep underground, lake water filters into the Chu River. The bottom of the lake contains the mineral monohydrocalcite: one of the few known lacustrine deposits.[4] The lake’s southern shore is dominated by the ruggedly beautiful Tian Shan mountain range. The lake water has salinity of approx. 0.6%—compare to 3.5% salinity of typical seawater—and its level drops by approximately 5 cm per year.[5] Administratively, the lake and the adjacent land are within Issyk Kul Province of Kyrgyzstan. Tourism During the Soviet era, the lake became a popular vacation resort, with numerous sanatoria, boarding houses and vacation homes along its northern shore, many concentrated in and around the town of Cholpon-Ata. These fell on hard times after the break-up of the USSR, but now hotel complexes are being refurbished and simple private bed-and-breakfast pensions are being established for a new generation of health and leisure visitors. The city of Karakol (formerly Przhevalsk, after the Russian explorer Przhevalsky who died there) is the administrative seat of Issyk Kul Oblast (Province) of Kyrgyzstan. It is located near the eastern tip of the lake and is a good base for excursions into the surrounding area. Its small old core contains an impressive wooden mosque, built without metal nails by the Dungan people, and a wooden Orthodox church that was used as a stable during Soviet times (see state atheism). History Lake Issyk Kul was a stopover on the Silk Road, a land route for travelers from the Far East to Europe. Many historians believe that the lake was the point of origin for the Black Death that plagued Europe and Asia during the early and mid-14th century.[6] The lake’s status as a byway for travelers allowed the plague to spread across these continents via medieval merchants who unknowingly carried infested vermin along with them. A 14th century Armenian monastery was found on the northeastern shores of the lake by retracing the steps of a medieval map used by Venetian merchants on the Silk Road. On the beach at Koshkol’ The lake level was some 8 metres (26 ft) lower in medieval times. Divers have found the remains of drowned settlements in shallow areas around the lake. In December 2007, a report was released by a team of Kyrgyz historians, led by Vladimir Ploskikh, vice president of the Kyrgyz Academy of Sciences, that archaeologists have discovered the remains of a 2500-year-old advanced civilization at the bottom of the Lake. The data and artifacts obtained suggest that the ancient city was a metropolis in its time. The discovery consisted of formidable walls, some stretching for 500 metres (1,600 ft) as well as traces of a large city with an area of several square kilometers. Other findings included Scythian burial mounds eroded over the centuries by waves, as well as numerous well-preserved artifacts, including bronze battleaxes, arrowheads, self-sharpening daggers, objects discarded by smiths, casting molds, and a faceted gold bar that was a monetary unit of the time. Articles identified as the world’s oldest extant coins were also found underwater with gold wire rings used as small change and a large hexahedral goldpiece. Also found was a bronze cauldron with a level of craftsmanship that is today achieved by using an inert gas environment.[1][7][8] Issyk Kul beach (2002) Fish The lake contains highly endemic fish biodiversity, and some of the species, including four endemics, are seriously endangered. In recent years catches of all species of fish have declined markedly, due to a combination of over-fishing, heavy predation by two of the introduced species, and the cessation of lake restocking with juvenile fish from hatcheries. At least four commercially targeted endemic fish species are sufficiently threatened to be included in the Red Book of the Kyrgyz Republic: Schmidt’s Dace (Leuciscus schmidti), Issyk-Kul Dace (Leuciscus bergi), Marinka (Schizothorax issyk-kuli), and Sheer or Naked Osman (Diptychus dybovskii). Seven other endemic species are almost certainly threatened as by-catch or are indirectly impacted by fishing activity and changes to the structure and balance of the lake’s fish population. Sevan trout, a fish endemic to Lake Sevan in Armenia, was introduced into Issyk-Kul in the 1970s. While this fish is an endangered species in its  home  lake, it has a much better chance to survive in Lake Issyk-Kul where it has ravaged the indigenous species. The Legend of its Creation In pre-Islamic legend, the king of the Ossounes had donkey’s ears. He would hide them, and order each of his barbers killed to hide his secret. One barber yelled the secret into a well, but he didn’t cover the well after. The well water rose and flooded the kingdom. The kingdom is today under the waters of Issyk-Kul. This is how the lake was formed, according to the legend. Other legends say that four drowned cities lie at the bottom of the lake. Substantial archaeological finds indicating the presence of an advanced civilization in ancient times have been made in shallow waters of the lake.[8] Russian Navy test site During the Soviet period, the Soviet Navy operated an extensive facility at the lake’s eastern end, where submarine and torpedo technology was evaluated.[9] In March 2008, Kyrgyz newspapers reported that 866 hectares (2,140 acres) around the Karabulan peninsula on the lake would be leased for an indefinite period to the Russian Navy, which is planning to establish new naval testing facilities as part of the 2007 bilateral Agreement on Friendship, Cooperation, Mutual Help, and Protection of Secret Materials. The Russian military will pay $4.5 million annually to lease the area.[10] Issyk Kul at sundown (2002) Lakeside towns Towns and some villages around the lake, listed clockwise from the lake’s western tip: * Balykchy (the railhead at the western end of the lake) * Koshkol’ * Cholpon-Ata (the capital of the north shore) * Karakol (the provincial capital near the eastern end of the lake) * Tyup Geography portal Search Wikimedia Commons     Wikimedia Commons has media related to: Issyk Kul 1. ^ a b ANI (2007-12-28).  Archaeologists discover remains of 2500-year-old advanced civilization in Russia . Yahoo  News. Archived from the original on 20080101. http://web.archive.org/web/20080101111204/http://in.news.yahoo.com/071228/139/6oy8j.html . 2. ^ International Lake Environment Committee Foundation 3. ^ V.V.Romanovsky,  Water level variations and water balance of Lake Issyk Kul , in Jean Klerkx, Beishen Imanackunov (2002), p.52 4. ^ Sapozhnikov DG, Tsvetkov AI (1959).  Precipitation of hydrous calcium carbonate on the bottom of Lake Issyk-Kul . Doklady Akademii Nauk SSSR 24: l3l-133. 5. ^ Lake Issyk-Kool 6. ^ The Silk Route – Channel 4 7. ^ Advanced Russian civilization found-Health/Sci-The Times of India 8. ^ a b Lukashov, Nikolai. Ancient Civilization Discovered at the Bottom of Lake Issyk Kul in the Kyrgyz Mountains. Ria Novosti. December 27, 2007. Accessed on: July 24, 2008. 9. ^ Kommersant-Vlast, ‘Vys Rossiya Armia’, 2005 10. ^ RFE/RL NEWSLINE Vol. 12, No. 51, Part I, 14 March 2008 External links * Guide to Issyk Kul from the Spektator Magazine * World Lake Database entry for Lake Issyk-Kul * The Issyk-Kul Hollow at Natural Heritage Protection Fund * Remains of ancient civilization discovered on the bottom of issyk-kul lake * Photographs of Issyk-Kul sites * Jean Klerkx, Beishen Imanackunov (eds.):  Lake Issyk-Kul: Its Natural Environment . Springer, 2002. ISBN 1402009003. (Searchable text on Google Books) * Touristic information about Issyk Kul List of seas Antarctic Ocean Amundsen Sea A Bass Strait A Bellingshausen Sea A Davis Sea A Great Australian Bight A Gulf Saint Vincent A Ross Sea A Scotia Sea A Spencer Gulf A Weddell Sea Arctic Ocean Amundsen Gulf A Baffin Bay A Barents Sea  A Beaufort Sea A Bering Sea A Chukchi Sea A East Siberian Sea A Greenland Sea A Hudson Bay A James Bay A Kara Sea A Kara Strait A Laptev Sea A Lincoln Sea A Prince Gustav Adolf Sea A Pechora Sea A White Sea Atlantic Ocean Adriatic Sea A Aegean Sea A Alboran Sea A Argentine Sea A Balearic Sea A Baltic Sea A Bay of Biscay A Bay of Bothnia A Bay of Campeche A Bay of Fundy A Black Sea A Bothnian Sea A Caribbean Sea A Celtic Sea A Central Baltic Sea A Chesapeake Bay A Davis Strait A Denmark Strait A English Channel A Gulf of Bothnia A Gulf of Finland A Gulf of Guinea A Gulf of Mexico A Gulf of Sidra A Gulf of St. Lawrence A Gulf of Venezuela A Ionian Sea A Labrador Sea A Ligurian Sea A Irish Sea A Marmara Sea A Mediterranean Sea A Myrtoan Sea A North Sea A Norwegian Sea A Sargasso Sea A Sea of Azov A Sea of Crete A Sea of the Hebrides A Thracian Sea A Tyrrhenian Sea Indian Ocean Andaman Sea A Arabian Sea A Bay of Bengal A Gulf of Aden A Gulf of Oman A Mozambique Channel A Persian Gulf A Red Sea A Timor Sea Pacific Ocean Arafura Sea A Banda Sea A Bering Sea A Bismarck Sea A Bohai Sea A Bohol Sea A Camotes Sea A Celebes Sea A Ceram Sea A Chilean Sea A Coral Sea A East China Sea A Flores Sea A Gulf of Alaska A Gulf of California A Gulf of Carpentaria A Gulf of Thailand A Halmahera Sea A Java Sea A Koro Sea A Molucca Sea A Philippine Sea A Savu Sea A Sea of Japan A Sea of Okhotsk A Seto Inland Sea A Sibuyan Sea A Solomon Sea A South China Sea A Sulu Sea A Tasman Sea A Visayan Sea A Yellow Sea Landlocked seas Aral Sea A Caspian Sea A Chott Melrhir A Dead Sea A Great Lakes A Great Salt Lake A Issyk Kul A Lake Balkhash A Lake Chad A Lake Chilwa A Lake Sevan A Lake Turkana A Lake Urmia A Lake Van A Namtso A Pyramid Lake A Qinghai Lake A Salton Sea A Tonlé Sap Retrieved from  http://en.wikipedia.org/wiki/Issyk_Kul Categories: Archaeological sites in Kyrgyzstan | Lakes of Kyrgyzstan | Endorheic lakes | Mountain lakes | Issyk Kul Province | Biosphere reserves of Kyrgyzstan | Ramsar sites in Kyrgyzstan | Sites along the Silk Road Hidden categories: Articles containing Kyrgyz language text | Articles containing Russian language text | Articles containing Chinese language text * This page was last modified on 17 August 2009 at 20:37. http://en.wikipedia.org/wiki/Issyk_Kul *** In March 2008, Kyrgyz newspapers reported that 866 hectares (2,140 acres) around the Karabulan peninsula on the lake would be leased for an indefinite period to the Russian Navy, which is planning to establish new naval testing facilities as part of the 2007 bilateral Agreement on Friendship, Cooperation, Mutual Help, and Protection of Secret Materials. The Russian military will pay $4.5 million annually to lease the area.[10] *** From Wikipedia, the free encyclopedia Manas International Airport Airport type     Joint (Civil and Military) Location     Bishkek Elevation AMSL     2,058 ft / 627 m Coordinates     43°03?40.7?N 74°28?39.2?E? / ?43.061306°N 74.477556°E? / 43.061306; 74.477556Coordinates: 43°03?40.7?N 74°28?39.2?E? / ?43.061306°N 74.477556°E? / 43.061306; 74.477556 Runways ft     m 08/26     13,780     4,200     Concrete Manas International Airport (IATA: FRU, ICAO: UAFM) is the main international airport in Kyrgyzstan located 25 km (16 mi) north-northwest of the capital Bishkek. The airport is operational 24 hours and its ILS system is ICAO CAT 2. Fog can cause heavy delays especially for long haul flights.[1] It is also the site of the Transit Center at Manas, formerly known as Manas Air Base, a US Air Force base supporting Operation Enduring Freedom and the International Security Assistance Force in Afghanistan. In 2007, 625,500 passengers passed through the airport, an increase of 21% over the previous year. 23,172 tonnes of cargo were also processed in 2007. Contents * 5 External links History The airport was constructed as a replacement for the old Bishkek airport that was located to the south of the city, and named after the Kyrgyz epic hero, Manas, at the suggestion of country’s most prominent writer and intellectual, Chinghiz Aitmatov. The first plane landed at Manas in October 1974, with Soviet Premier Alexey Kosygin on board. Aeroflot operated the airport’s first scheduled flight to Moscow-Domodedovo on 4 May 1975. When Kyrgyzstan gained independence from the Soviet Union in 1991, the airport began a slow but steady decline as its infrastructure remained neglected for almost ten years and a sizable aircraft boneyard developed; approximately 60 derelict aircraft from the Soviet era, ranging in size from helicopters to full-sized airliners, were left in mothballs on the airport ramp at the Eastern end of the field. With the beginning of Operation Enduring Freedom, the United States and its coalition partners immediately sought permission from the Kyrgyz government to use the airport as a military base for operations in Afghanistan. Coalition forces arrived in late December 2001 and immediately the airport saw unprecedented expansion of operations and facilities.[2] The derelict aircraft were rolled into a pasture next to the ramp to make room for coalition aircraft, and large, semi-permanent hangars were constructed to house coalition fighter aircraft. Additionally, a Marsden Matting parking apron was built along the Eastern half of the runway, along with a large cargo depot and several aircraft maintenance facilities. A tent city sprang up across the street from the passenger terminal, housing over 2,000 troops. The American forces christened the site  Ganci Air Base , after New York Fire Department chief Peter J. Ganci, Jr., who was killed in the September 11 terrorist attacks. It was later given the official name of Manas Air Base. In 2004, a new parking ramp was added in front of the passenger terminal to make room for larger refueling and transport aircraft such as the KC-135 and C-17. Around the same time the Kyrgyz government performed a major expansion and renovation of the passenger terminal, funded in part by the sizable landing fees paid by coalition forces. Several restaurants, gift shops, and barber shops sprang-up in the terminal catering to the deployed troops. The airport terminal underwent renovation and redesign in 2007 [3]. Airlines and destinations The following airlines have scheduled services from Manas International Airport Airlines  ?     Destinations Aeroflot     Moscow-Sheremetyevo Uzbekistan Airways     Tashkent Incidents and accidents * In the predawn hours of 23 October, 2002, an IL-62 airliner operated by the Tretyakovo Air Transport Company crashed on takeoff after running off the end of the runway. There were no passengers aboard and all eleven crew members escaped, with only minor injuries. They were treated at the joint US Air Force and South Korean army clinic at Manas Air Base. The wreckage was bulldozed by Kyrgyz personnel and left at the site. Airport operations resumed before the crash site had finished smoldering.[4] * In November 2004, a civilian Boeing 747 cargo transport took a wrong turn from the runway towards the new Marsden Matting fighter ramp. The jumbo jet was too large and heavy to taxi forward onto the taxiway and with no ability to move in reverse it was effectively stuck in place with its tail section blocking the runway. Airport operations were halted for several hours until a tractor could tow the 747 into a position from which it could taxi to the parking ramp. * On 26 September, 2006, a Kyrgyzstan Airlines Tupolev Tu-154 aircraft taking off for Moscow-Domodedovo collided on the runway with a US Air Force KC-135 tanker that had just landed. The Tupolev, with 52 passengers and nine crew on board, lost part of its wing but was able to take off and return to make a safe landing with a 2.5m section of its wing missing. The KC-135, with three crew members and a cargo consisting entirely of highly-flammable jet fuel, caught fire and was destroyed. There were no injuries on either aircraft.[5] * On 24 August, 2008 an Itek Air Boeing 737 heading to Tehran with 90 people aboard crashed 3 km from the airport, killing 68. Twenty-two people, including two crew members, survived the crash. According to an airport official, the crew had reported a technical problem on board and were returning to the airport when the plane went down.[6] Main article: Iran Aseman Airlines Flight 6895 References 1. ^ A-Z World Airports Online – Manas International Airport 2. ^ Bishkek: A hub to the Far East 3. ^ Manas airport in Bishkek is completely modernised (in Russian) 4. ^ Airline Disaster Database: 23 Oct 2002 5. ^ Flight International, 3-9 October 2006 6. ^ . The crash is the worst ever aviation accident in Kyrgyzstan.68 die, 22 survive airliner crash in Kyrgyzstan External links Search Wikimedia Commons     Wikimedia Commons has media related to: Manas International Airport * Manas International Airport (official site) * Manas International Airport (globalsecurity.org) * Accident history for FRU at Aviation Safety Network * Airport information for UAFM at Great Circle Mapper. Source: DAFIF (effective Oct. 2006). * Current weather for UAFM at NOAA/NWS * Airport information for UAFM at World Aero Data. Data current as of October 2006.. Source: DAFIF. Retrieved from  http://en.wikipedia.org/wiki/Manas_International_Airport Categories: Airports in Kyrgyzstan | Airports built in the Soviet Union | Soviet Air Force bases | Chuy Province | Bishkek Area     43,100 km² (16,641 sq mi) Population     450,700 (2005) Density     10.5 /km² (27 /sq mi) Governor     Emilbek Anapiyaev ISO 3166-2     KG-Y Issyk Kul at sundown Issyk Kul Province (Kyrgyz: ????-??? ???????) is a province (oblast) of Kyrgyzstan. Its capital is Karakol. It is surrounded by Almaty Province, Kazakhstan( north), Chui Province (west), Naryn Province (southwest) and Xinjiang, China (southeast). The north is dominated by the eye-shaped Lake Issyk Kul, with the Kungey Alatau mountains to the north and the Terskey Alatau to the south (‘sunny’ and ‘shady’ Alatau). To the south is mountains and ‘jailoos’ (mountain meadows used for summer grazing). The far east contains the highest Tian Shan mountains with Khan Tengri. Most of the population is around the lake, with Balykchy in the west and Karakol in the east. The railroad from the north ends at Balykchy. The main highway (A365) from Bishkek passes through Balykchy and into Naryn Province on its way to the Torugart Pass into China. Highway A363 circles the lake and A362 runs east from the lake into Kazakhstan. The province, which resembles the Alps or Colorado, would be a major tourist destination were it not for its remoteness, underdeveloped infrastructure, and growing conflict between Kyrgyz nationalists and independence factions, which in December 2008 flared up again, killing 39 civilians. Currently, it is visited mostly by locals who use the soviet-era establishments around the lake and the more adventurous sort of international tourist. There is a village by the name of Kyzyldzhildyz in this province. It’s name is hard enough to pronounce for foreigners to the language that the village’s mayor has offered a reward for any American that can pronounce  Kyzyldzhildyz . Districts of Issyk Kul Issyk Kul is divided administratively into 5 districts: [1]: District     Capital * Laurence Mitchell, Kyrgyzstan, Bradt Travel Guides, 2008 External links * Guide to the region from the Spektator magazine * (English) Karakol – Djeti-Oguz region in Central Tien-Shan (Mountaineering reports and maps. Although the site is in English, with some web browsers you may need to set  Character Encoding  to  Cyrillic  in the  View  menu of your browser in order to get better display of the main page). Search Wikimedia Commons     Wikimedia Commons has media related to: Issyk Kul Province Oblastlar of Kyrgyzstan Batken A Chuy A Issyk Kul A Jalal-Abad A Naryn A Osh A Talas Flag of Kyrgyzstan Stub icon     This Issyk-Kul province location article is a stub. You can help Wikipedia by expanding it. Kumtor Gold Mine From Wikipedia, the free encyclopedia Kumtor Gold Mine is an open-pit gold mining site in Issyk Kul Province of Kyrgyzstan located about 350 km (220 mi) southeast of the capital Bishkek and 80 km (50 mi) south of Lake Issyk-Kul near the border with China. Kumtor is 100% owned by the Canadian mining company, Centerra Gold, through its wholly owned subsidiary, Kumtor Gold Company. The mine started operation in Q2 1997 and produced more than 5.8 million ounces (180,000 kg) of gold through the end of 2006. Located in Tian Shan mountains at more than 4,000 m (14,000 ft) above sea level, Kumtor is the second-highest gold mining operation in the world after Yanacocha gold mine in Peru. The mine was linked to a major environmental incident in 1998 when a truck carrying 1762 kg of sodium cyanide (a chemical used to dissolve gold from granulated ore the use of which is highly controversial) fell into the Barskaun River on the way to Kumtor. External links * Centerra Gold – Kumtor Gold Mine web page Coordinates: 41°52?N 78°12?E? / ?41.867°N 78.2°E? / 41.867; 78.2 Retrieved from  http://en.wikipedia.org/wiki/Kumtor_Gold_Mine Categories: Geography of Kyrgyzstan | Economy of Kyrgyzstan | Gold mines in Kyrgyzstan | Issyk Kul Province | Economy of the Soviet Union | Surface mines in Kyrgyzstan Overview Conveying mill feed from the crusher at Kumtor Centerra owns 100% of the Kumtor gold mine through its wholly owned subsidiary Kumtor Gold Company. Kumtor is located in the Kyrgyz Republic, about 350 kilometres southeast of the capital Bishkek and about 60 kilometres north of the border with the Peoples Republic of China. It is the largest gold mine operated in Central Asia by a Western-based company, having produced more than 6 million ounces of gold between 1997 and the end of 2007. In 2008 gold production exceeded 556,000 ounces. The Kumtor gold deposit is located in the southern Tien Shan Metallogenic Belt, a major suture that traverses Central Asia, from Uzbekistan in the west through Tajikistan and the Kyrgyz Republic into northwestern China, a distance of more than 1,500 kilometres. A number of important mesothermal-type gold deposits occur along this belt including Muruntau, Zarmitan, Jilau and Kumtor. Production Charts of Ore mined *** Overview The Boroo mine and mill complex, about 110 kilometers northwest of Ulaanbaatar, Mongolia Centerra Gold has a 100% equity interest in Boroo, the first significant foreign investment for industrial development in Mongolia since 1979. Located 110 kilometers west-northwest of Ulaanbaatar, the country’s capital, Boroo began commercial production on March 1, 2004 and produced more than 245,000 ounces of gold (including gold produced during commissioning) by year-end. The Boroo gold deposit is generally flat lying or sub-horizontal and extends over an area measuring 2.5 by 1.5 kilometres. Throughout the area, a series of mineralized zones occur up to 400 metres wide and typically average from 10 to 30 metres in thickness. While Boroo is located in a relatively remote area of the world, it is well positioned with respect to existing infrastructure. The paved all-weather Ulaanbaatar – Irkutsk highway passes within three kilometers of the mine site. The main Trans-Mongolian railway, which links Ulaanbaatar with Irkutsk, Russia and Beijing, China, runs through Baruunkharaa, about 20 kilometers to the north of the mine site. http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=39835 Dust plumes formed over the Taklimakan Desert in mid-August 2009. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this image of the western half of the desert on August 15, 2009, on the third consecutive day of dust storm activity. Nearly opaque dust not only fills the western half of the Tarim Basin in which the Taklimakan Desert sits, but even pushes past the basin’s northwestern rim. From its western edge, the dust cloud forms a V shape that opens toward the east. The dust’s thickness may be slightly exaggerated in this image as this area has been observed near the edge of the satellite swath (where the satellite has to look through a longer path of the atmosphere to see the ground). The Taklimakan Desert sits between the mountain ranges of the Tien Shan (or Tian Shan) in the north and the Kunlun Shan in the south. Far from any ocean, the desert experiences few, if any, effects of the rainy season of the Asian monsoon that waters other parts of the continent. Because the basin lacks drainage, any water that enters it can only evaporate away, leaving behind salt. The Taklimakan Desert qualifies as China’s biggest, hottest, and driest. It also qualifies as one of the world’s largest shifting sand deserts, with dunes reaching a height of up to 200 meters (656 feet). References World Wildlife Fund, McGinley, M. (2007). Taklimakan Desert. Encyclopedia of Earth. Accessed August 17, 2009. NASA image courtesy MODIS Rapid Response Team, Goddard Space Flight Center. Caption by Michon Scott. Instrument: An interview with Sean Gallagher The Beijinger July 3, 2009 In April 2009, British photojournalist Sean Gallagher traveled 4000km through Inner Mongolia, Ningxia, Gansu and Xinjiang documenting China’s struggle with desertification. An exhibit of “China’s Growing Sands” will be opening on July 4, at 6pm at Café Zarah, on 42 Gulou Dongdajie (8403 9807) and will run through August 5. The opening, which is open to all, will include a 15-minute multimedia presentation by Gallagher. The Beijinger asked Gallagher a few questions about his work: [etc.] What effect is desertification having on China and the world? It is estimated that desertification affects 400 million people in China alone. These effects come in a myriad of forms including disappearing water, degraded grasslands, moving sands and environmental refugees. Sandstorms originating in China have been known to spread to the Korean Peninsula, Japan and even as far as the west coast of the United States. As former UN Secretary General Kofi Annan said in a message on World Day to Combat Desertification and Drought in 2006, “Desertification is one of the most serious threats facing humanity.” What causes it? Desertification is not caused by one single factor. It is usually caused by a combination of factors including drought, deforestation, mis-use of water, inappropriate farming methods and climate change. What is being done to combat it? Desertification is not an issue that the authorities take lightly. Projects such as the planting of the “Great Green Wall”, a chain of trees thousands of kilometers in length, is currently taking place in the north of China. It is aimed at stabilizing soil and protecting the capital from seasonal sandstorms. Research is also being undertaken throughout China at places such as the Turpan Desert Botanical Garden and Shapotou Desert Research Center. Here, scientists are studying plants to find the best species to ‘fix’ sands and return land to a level of productivity. The main problem is that the task is huge and the affected areas are so large. It is estimated that nearly 20 percent of China is now classified as desert. [ . . . ] What does desertification mean for Beijing residents? Sandstorms are the most visually obvious example of the effects of desertification in Beijing. However I don’t think the capital will ever become a desert per se. The idea of desertification conjures up images of huge sand dunes swallowing homes and lands. Whilst this does actually occur in places in China, the threat to Beijing of this is extremely small. The nearest desert to Beijing is in Tianmo, about 90 kilometers north of the city and it is a relatively small dune system. Desertification is about aridity and this is the main factor facing Beijing and the north of China. Drought in the north is a well-documented problem, and the immense project of channeling water from the south of the country continues to be a hot topic. The associated problems with drought include the impact to the agriculture industry and shortages of drinking water, which will have direct effects on the residents of Beijing. April 27, 2008 — Updated 0357 GMT (1157 HKT) By Matt Ford For CNN Desertification: How to stop the shifting sands These huge, sky-blackening dust storms sweep across Asia in March and April, bringing with them millions of tons of sand from inner Mongolia and depositing it in China and on across the Korean peninsula to Japan. During the past few years the storms have grown in ferocity and scale, and they are at the vanguard of an advancing Gobi desert that threatens more than 400 million people in the Chinese provinces of Xinjiang, Inner Mongolia, Gansu, Ningxia and Shaanxi. The economic toll has been estimated to cost the Chinese economy $6.5 billion per year. But desertification is not limited to China and it is fast becoming a serious global problem that will only be exacerbated by climate change. [etc.]

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What type of rock is granite?

Granite - Igneous Rock Types Igneous Rock Types Pictures of Igneous Rock Types Use Deep Earth and Other Planets Granite consists of quartz (gray), plagioclase feldspar (white) and alkali feldspar (beige) plus dark minerals, in this case biotite and hornblende . (more below) "Granite" is used by the public as a catch-all name for any light-colored, coarse-grained igneous rock. The geologist examines these in the field and calls them granitoids pending laboratory tests. The key to true granite is that it contains sizable amounts of quartz and both kinds of feldspar. This article goes much deeper into granite . This granite specimen comes from the Salinian block of central California, a chunk of ancient crust carried up from southern California along the San Andreas fault. Pictures of other granite specimens appear in the granite picture gallery . Also see the granite landforms of Joshua Tree National Park . And big closeup pictures of granite are available in the closeup rock wallpaper photos . Photo Credit: Photo (c) 2004 Andrew Alden, licensed to About.com ( fair use policy )

Igneous rock

What type of rock is basalt?

The 3 basic rock types Ask GeoMan... What are the 3 basic types of rocks? Just as any person can be put into one of two main categories of human being, all rocks can be put into one of three fundamentally different types of rocks. They are as follows: Igneous Rocks Igneous rocks are crystalline solids which form directly from the cooling of magma. This is an exothermic process (it loses heat) and involves a phase change from the liquid to the solid state. The earth is made of igneous rock - at least at the surface where our planet is exposed to the coldness of space. Igneous rocks are given names based upon two things: composition (what they are made of) and texture (how big the crystals are). Click here for more on igneous rock composition and texture. Click here for more on elements and minerals common in igneous rocks. Click here for more on magma and igneous rocks. Click here for more on plate tectonics and the formation of magma. Click here for a chart summarizing the main divisions of igneous rocks. Click here for more on basalt and granite.   Sedimentary Rocks In most places on the surface, the igneous rocks which make up the majority of the crust are covered by a thin veneer of loose sediment, and the rock which is made as layers of this debris get compacted and cemented together. Sedimentary rocks are called secondary, because they are often the result of the accumulation of small pieces broken off of pre-existing rocks. There are three main types of sedimentary rocks: Clastic: your basic sedimentary rock. Clastic sedimentary rocks are accumulations of clasts: little pieces of broken up rock which have piled up and been "lithified" by compaction and cementation. Chemical: many of these form when standing water evaporates, leaving dissolved minerals behind. These are very common in arid lands, where seasonal "playa lakes" occur in closed depressions. Thick deposits of salt and gypsum can form due to repeated flooding and evaporation over long periods of time . Organic: any accumulation of sedimentary debris caused by organic processes. Many animals use calcium for shells, bones, and teeth. These bits of calcium can pile up on the seafloor and accumulate into a thick enough layer to form an "organic" sedimentary rock. Click here for more on sedimentary processes and rocks (RCC). Click here for more on sedimentary rocks (GPHS).   Metamorphic Rocks The metamorphics get their name from "meta" (change) and "morph" (form). Any rock can become a metamorphic rock. All that is required is for the rock to be moved into an environment in which the minerals which make up the rock become unstable and out of equilibrium with the new environmental conditions. In most cases, this involves burial which leads to a rise in temperature and pressure. The metamorphic changes in the minerals always move in a direction designed to restore equilibrium. Common metamorphic rocks include slate, schist, gneiss, and marble. Click here for more on metamorphic processes and rocks (RCC). Click here for more on metamorphic rocks (GPHS).  

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What is the main constituent of natural gas?

Components of Natural Gas - Enbridge Gas Distribution Components of Natural Gas Components of Natural Gas Properties of Natural Gas Natural gas is a colourless, tasteless, odourless, and non-toxic gas. Because it is odourless, mercaptan is added to the natural gas, in very small amounts to give the gas a distinctive smell of rotten eggs. This strong smell can alert you of a potential gas leak . Natural gas is about 40 per cent lighter than air, it has a high ignition temperature and a narrow flammability range, meaning natural gas will ignite at temperatures above 1,000 degrees and burn at a mix of approximately 4-15 per cent volume in air. For more information on natural gas, visit the  Canadian Gas Association . To learn more about the physical properties of natural gas, download our Material Safety Data Sheet (MSDS): Fiche technique pour le gaz naturel Chemical Composition of Natural Gas Natural gas is primarily composed of methane, but also contains ethane, propane and heavier hydrocarbons. It also contains small amounts of nitrogen, carbon dioxide, hydrogen sulphide and trace amounts of water. The monthly average chemical compositions of natural gas for Victoria Square, which supplies the Greater Toronto Area, are provided below:

Methane

Which of the Earth's atmospheric layers reflects radio waves?

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Which gas forms 80% of Earth's atmosphere?

Introduction to the Atmosphere: Background Material Introduction to the Atmosphere This section provides a brief overview of the properties associated with the atmosphere. The general concepts found in this section are: The earth's atmosphere is a very thin layer wrapped around a very large planet. Two gases make up the bulk of the earth's atmosphere: nitrogen ( ), which comprises 78% of the atmosphere, and oxygen ( ), which accounts for 21%. Various trace gases make up the remainder. Based on temperature, the atmosphere is divided into four layers: the troposphere, stratosphere, mesosphere, and thermosphere. Energy is transferred between the earth's surface and the atmosphere via conduction, convection, and radiation. Ocean currents play a significant role in transferring this heat poleward. Major currents, such as the northward flowing Gulf Stream, transport tremendous amounts of heat poleward and contribute to the development of many types of weather phenomena. This section includes seven classroom activities. Atmospheric Properties The thin envelope of air that surrounds our planet is a mixture of gases, each with its own physical properties. The mixture is far from evenly divided. Two elements, nitrogen and oxygen, make up 99% of the volume of air. The other 1% is composed of "trace" gases, the most prevalent of which is the inert gaseous element argon. The rest of the trace gases, although present in only minute amounts, are very important to life on earth. Two in particular, carbon dioxide and ozone, can have a large impact on atmospheric processes. Another gas, water vapor, also exists in small amounts. It varies in concentration from being almost non-existent over desert regions to about 4% over the oceans. Water vapor is important to weather production since it exists in gaseous, liquid, and solid phases and absorbs radiant energy from the earth. Structure of the Atmosphere The atmosphere is divided vertically into four layers based on temperature: the troposphere, stratosphere, mesosphere, and thermosphere. Throughout the Cycles unit, we'll focus primarily on the layer in which we live - the troposphere. Troposphere The word troposphere comes from tropein, meaning to turn or change. All of the earth's weather occurs in the troposphere. The troposphere has the following characteristics. It extends from the earth's surface to an average of 12 km (7 miles). The pressure ranges from 1000 to 200 millibars (29.92 in. to 5.92 in.). The temperature generally decreases with increasing height up to the tropopause (top of the troposphere); this is near 200 millibars or 36,000 ft. The temperature averages 15°C (59°F) near the surface and -57°C (-71°F) at the tropopause. The layer ends at the point where temperature no longer varies with height. This area, known as the tropopause, marks the transition to the stratosphere. Winds increase with height up to the jet stream. The moisture concentration decreases with height up to the tropopause. The air is much drier above the tropopause, in the stratosphere. The sun's heat that warms the earth's surface is transported upwards largely by convection and is mixed by updrafts and downdrafts. The troposphere is 70% Atmospheric Processes Interactions - Atmosphere and Ocean In the Cycles overview, we learned that water is an essential part of the earth's system. The oceans cover nearly three-quarters of the earth's surface and play an important role in exchanging and transporting heat and moisture in the atmosphere. Most of the water vapor in the atmosphere comes from the oceans. Most of the precipitation falling over land finds its way back to oceans. About two-thirds returns to the atmosphere via the water cycle. You may have figured out by now that the oceans and atmosphere interact extensively. Oceans not only act as an abundant moisture source for the atmosphere but also as a heat source and sink (storage). The exchange of heat and moisture has profound effects on atmospheric processes near and over the oceans. Ocean currents play a significant role in transferring this heat poleward. Major currents, such as the northward flowing Gulf Stream, transport tremendous amounts of heat poleward and contribute to the development of many types of weather phenomena. They also warm the climate of nearby locations. Conversely, cold southward flowing currents, such as the California current, cool the climate of nearby locations. Energy Heat Transfer Practically all of the energy that reaches the earth comes from the sun. Intercepted first by the atmosphere, a small part is directly absorbed, particularly by certain gases such as ozone and water vapor. Some energy is also reflected back to space by clouds and the earth's surface. Energy is transferred between the earth's surface and the atmosphere via conduction, convection, and radiation. Conduction is the process by which heat energy is transmitted through contact with neighboring molecules. Some solids, such as metals, are good conductors of heat while others, such as wood, are poor conductors. Air and water are relatively poor conductors. Since air is a poor conductor, most energy transfer by conduction occurs right at the earth's surface. At night, the ground cools and the cold ground conducts heat away from the adjacent air. During the day, solar radiation heats the ground, which heats the air next to it by conduction. Convection transmits heat by transporting groups of molecules from place to place within a substance. Convection occurs in fluids such as water and air, which move freely. In the atmosphere, convection includes large- and small-scale rising and sinking of air masses and smaller air parcels. These vertical motions effectively distribute heat and moisture throughout the atmospheric column and contribute to cloud and storm development (where rising motion occurs) and dissipation (where sinking motion occurs). To understand the convection cells that distribute heat over the whole earth, let's consider a simplified, smooth earth with no land/sea interactions and a slow rotation. Under these conditions, the equator is warmed by the sun more than the poles. The warm, light air at the equator rises and spreads northward and southward, and the cool dense air at the poles sinks and spreads toward the equator. As a result, two convection cells are formed. Meanwhile, the slow rotation of the earth toward the east causes the air to be deflected toward the right in the northern hemisphere and toward the left in the southern hemisphere. This deflection of the wind by the earth's rotation is known as the Coriolis effect. Radiation is the transfer of heat energy without the involvement of a physical substance in the transmission. Radiation can transmit heat through a vacuum. Energy travels from the sun to the earth by means of electromagnetic waves. The shorter the wavelength, the higher the energy associated with it. This is demonstrated in the animation below. As the drill's revolutions per minute (RPMs) increase, the number of waves generated on the string increases, as does the oscillation rate. The same principle applies to electromagnetic waves from the sun, where shorter wavelength radiation has higher energy than longer wavelength radiation. Most of the sun's radiant energy is concentrated in the visible and near-visible portions of the spectrum. Shorter-than-visible wavelengths account for a small percentage of the total but are extremely important because they have much higher energy. These are known as ultraviolet wavelengths. Concluding Thoughts The physical and chemical structure of the atmosphere, the way that the gases interact with solar energy, and the physical and chemical interactions between the atmosphere, land, and oceans all combine to make the atmosphere an integral part of the global biosphere. For students to truly understand the nature and importance of the atmosphere, they should understand the answers to these questions: What is the structure and composition of the atmosphere? How does solar energy influence the atmosphere? How does the atmosphere interact with land and oceans? How is heat transferred throughout the earth system? Activities

Nitrogen

In which mountain chain would you find Mount Everest?

BBC - GCSE Bitesize: The modern atmosphere Next Heat can be transferred from place to place by conduction [conduction: The transfer of heat energy through a material - without the material itself moving. ], convection [convection: The transfer of heat energy through a moving liquid or gas. ] and radiation [infrared radiation: Electromagnetic radiation emitted from a hot object. ]. Dark matt surfaces are better at absorbing heat energy than light shiny surfaces. Heat energy can be lost from homes in many different ways and there are ways of reducing these heat losses. The modern atmosphere You need to know the proportions of the main gases in the atmosphere. The Earth’s atmosphere has remained much the same for the past 200 million years. The pie chart shows the proportions of the main gases in the atmosphere. The composition of air The two main gases are both elements and account for about 99 percent of the gases in the atmosphere. They are: about 4/5 or 80 percent nitrogen (a relatively unreactive gas) about 1/5 or 20 percent oxygen (the gas that allows animals and plants to respire and for fuels to burn) The remaining gases, such as carbon dioxide, water vapour and noble gases such as argon, are found in much smaller proportions. Page:

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What is the collective term for substances such as coal, oil and natural gas, the burning of which produces carbon dioxide?

» Natural Gas and the Environment NaturalGas.org The Natural Gas Industry and the Environment Emissions from the Combustion of Natural Gas Natural gas is the cleanest of all the fossil fuels, as evidenced in the Environmental Protection Agency’s data comparisons in the chart below, which is still current as of 2010. Composed primarily of methane, the main products of the  combustion  of natural gas are carbon dioxide and water vapor, the same compounds we exhale when we breathe. Coal and oil are composed of much more complex molecules, with a higher carbon ratio and higher nitrogen and sulfur contents. This means that when combusted, coal and oil release higher levels of harmful emissions, including a higher ratio of carbon emissions, nitrogen oxides (NOx), and sulfur dioxide (SO2). Coal and fuel oil also release ash particles into the environment, substances that do not burn but instead are carried into the atmosphere and contribute to pollution. The combustion of natural gas, on the other hand, releases very small amounts of sulfur dioxide and nitrogen oxides, virtually no ash or particulate matter, and lower levels of carbon dioxide, carbon monoxide, and other reactive hydrocarbons. Fossil Fuel Emission Levels Source: EIA – Natural Gas Issues and Trends 1998   Natural gas, as the cleanest of the fossil fuels, can be used in many ways to help reduce the emissions of pollutants into the atmosphere. Burning natural gas in the place of other fossil fuels emits fewer harmful pollutants, and an increased reliance on natural gas can potentially reduce the emission of many of these most harmful pollutants. Pollutants emitted in the United States, particularly from the combustion of fossil fuels, have led to the development of many pressing environmental problems. Natural gas, emitting fewer harmful chemicals into the atmosphere than other fossil fuels, can help to mitigate some of these environmental issues. These issues include: Greenhouse Gas Emissions Source: Intergovernmental Panel on Climate Change-2007 Global warming, or the ‘greenhouse effect’ is an environmental issue that deals with the potential for global climate change due to increased levels of atmospheric ‘greenhouse gases’. There are certain gases in our atmosphere that serve to regulate the amount of heat that is kept close to the earth’s surface. Scientists theorize that an increase in these greenhouse gases will translate into increased temperatures around the globe, which would result in many disastrous environmental effects. In fact, the Intergovernmental Panel on Climate Change (IPCC) predicts in its ‘Fourth Assessment Report’ released in 2007 that during the 21st century, global average temperatures are expected to rise by between 2.0 and 11.5 degrees Fahrenheit.  A Fifth Assessment Report is expected to be released by the IPCC between 2013 and 2015. Power Plants Contribute to the Emission of Greenhouse Gases Source: API The principle greenhouse gases include water vapor, carbon dioxide, methane, nitrogen oxides, and some engineered chemicals such as cholorofluorocarbons. While most of these gases occur in the atmosphere naturally, levels have been increasing due to the widespread burning of fossil fuels by growing human populations. The reduction of greenhouse gas emissions has become a primary focus of environmental programs in countries around the world. One of the principle greenhouse gases is carbon dioxide. Although carbon dioxide does not trap heat as effectively as other greenhouse gases (making it a less potent greenhouse gas), the sheer volume of carbon dioxide emissions into the atmosphere is very high, particularly from the burning of fossil fuels. In fact, according to the Energy Information Administration in its December 2009 report ‘Emissions of Greenhouse Gases’ in the United States, 81.3 percent of greenhouse gas emissions in the United States in 2008 came from energy-related carbon dioxide. Source: EIA-Emissions of Greenhouse Gases Report 2009 Because carbon dioxide makes up such a high proportion of U.S. greenhouse gas emissions, reducing carbon dioxide emissions can play a pivotal role in combating the greenhouse effect and global warming. The combustion of natural gas emits almost 30 percent less carbon dioxide than oil, and just under 45 percent less carbon dioxide than coal. One issue that has arisen with respect to natural gas and the greenhouse effect is the fact that methane, the principle component of natural gas, is itself a potent greenhouse gas. Methane has an ability to trap heat almost 21 times more effectively than carbon dioxide. According to the Energy Information Administration , although methane emissions account for only 1.1 percent of total U.S. greenhouse gas emissions, they account for 8.5 percent of the greenhouse gas emissions based on global warming potential. Sources of methane emissions in the U.S. include the waste management and operations industry, the agricultural industry, as well as leaks and emissions from the oil and gas industry itself. A major study performed by the Environmental Protection Agency (EPA) and the Gas Research Institute (GRI), now  Gas Technology Institute , in 1997 sought to discover whether the reduction in carbon dioxide emissions from increased natural gas use would be offset by a possible increased level of methane emissions. The study concluded that the reduction in emissions from increased natural gas use strongly outweighs the detrimental effects of increased methane emissions.  More recently in 2011, researchers at the Carnegie Mellon University released  “Life cycle greenhouse gas emissions of Marcellus shale gas” , a report comparing greenhouse gas emissions from the Marcellus Shale region with emissions from coal used for electricity generation.  The authors found that wells in the Marcellus region emit 20 percent to 50 percent less greenhouse gases than coal used to produce electricity. In 1993, the natural gas industry joined with EPA in launching the Natural Gas STAR Program to reduce methane emissions.  The STAR program has chronicled dramatic reductions to methane emissions, since that time: EPA STAR data shows a reduction in methane emissions each year for the last 16 years More than 904 Billion cubic feet (Bcf) of methane emissions were eliminated through the STAR program 1993-2009; and In 2009 alone, the program reduced methane emissions by 86 Bcf. Thus the increased use of natural gas in the place of other, dirtier fossil fuels can serve to lessen the emission of greenhouse gases in the United States. For more information on the Greenhouse Effect, visit the EPA’s  climate change  site. Smog, Air Quality and Acid Rain Smog – Natural Gas Can Help Source: EPA Smog and poor air quality is a pressing environmental problem, particularly for large metropolitan cities. Smog, the primary constituent of which is ground level ozone, is formed by a chemical reaction of carbon monoxide, nitrogen oxides, volatile organic compounds, and heat from sunlight. As well as creating that familiar smoggy haze commonly found surrounding large cities, particularly in the summer time, smog and ground level ozone can contribute to respiratory problems ranging from temporary discomfort to long-lasting, permanent lung damage. Pollutants contributing to smog come from a variety of sources, including vehicle emissions, smokestack emissions, paints, and solvents. Because the reaction to create smog requires heat, smog problems are the worst in the summertime. Source: Environmental Protection Agency The use of natural gas does not contribute significantly to smog formation, as it emits low levels of nitrogen oxides, and virtually no particulate matter. For this reason, it can be used to help combat smog formation in those areas where ground level air quality is poor. The main sources of nitrogen oxides are electric utilities, motor vehicles, and industrial plants. Increased natural gas use in the electric generation sector, a shift to cleaner natural gas vehicles, or increased industrial natural gas use, could all serve to combat smog production, especially in urban centers where it is needed the most. Particularly in the summertime, when natural gas demand is lowest and smog problems are the greatest, industrial plants and electric generators could use natural gas to fuel their operations instead of other, more polluting fossil fuels. This would effectively reduce the emissions of smog causing chemicals, and result in clearer, healthier air around urban centers. For more information on smog, including the major contributors to smog formation and what is currently being done to combat smog levels, visit the EPA’s  smog  information section. Particulate emissions also cause the degradation of air quality in the United States. These particulates can include soot, ash, metals, and other airborne particles. A study by the  Union of Concerned Scientists  in 1998, entitled ‘Cars and Trucks and Air Pollution’, showed that the risk of premature death for residents in areas with high airborne particulate matter was 26 percent greater than for those in areas with low particulate levels. Natural gas emits virtually no particulates into the atmosphere: in fact, emissions of particulates from natural gas combustion are 90 percent lower than from the combustion of oil, and 99 percent lower than burning coal. Thus increased natural gas use in place of other dirtier hydrocarbons can help to reduce particulate emissions in the U.S.  Current consequences stemming from global warming raised by the Union of Concerned Scientists can be found on their  site . Acid rain  is another environmental problem that affects much of the Eastern United States, damaging crops, forests, wildlife populations, and causing respiratory and other illnesses in humans. Acid rain is formed when sulfur dioxide and nitrogen oxides react with water vapor and other chemicals in the presence of sunlight to form various acidic compounds in the air. The principle source of acid rain-causing pollutants, sulfur dioxide and nitrogen oxides, are coal fired power plants. Since natural gas emits virtually no sulfur dioxide, and up to 80 percent less nitrogen oxides than the combustion of coal, increased use of natural gas could provide for fewer acid rain causing emissions. Industrial and Electric Generation Emissions Pollutant emissions from the industrial sector and electric utilities contribute greatly to environmental problems in the United States. The use of natural gas to power both industrial boilers and processes and the generation of electricity can significantly improve the emissions profiles for these two sectors. Natural gas is becoming an increasingly important fuel in the generation of electricity. As well as providing an efficient, competitively priced fuel for the generation of electricity, the increased use of natural gas allows for the improvement in the emissions profile of the electric generation industry. According to the National Environmental Trust (NET), now  Pew Charitable Trusts  (PEW), in their 2002 publication entitled ‘Cleaning up Air Pollution from America’s Power Plants’, power plants in the U.S. account for 67 percent of sulfur dioxide emissions, 40 percent of carbon dioxide emissions, 25 percent of nitrogen oxide emissions, and 34 percent of mercury emissions. Coal fired power plants are the greatest contributors to these types of emissions. In fact, according to World Watch Report 184, natural gas combined cycle power plants emit half as much carbon dioxide as modern super critical coal plants. Emissions from Industrial Smokestacks Source: EPA Natural gas-fired electric generation and natural gas-powered industrial applications offer a variety of environmental benefits and environmentally friendly uses, including: Fewer Emissions – Combustion of natural gas, used in the generation of electricity, industrial boilers, and other applications, emits lower levels of NOx, CO2, and particulate emissions, and virtually no SO2 and mercury emissions. Natural gas can be used in place of, or in addition to, other fossil fuels, including coal, oil, or petroleum coke, which emit significantly higher levels of these pollutants. Reduced Sludge – Coal-fired power plants and industrial boilers that use scrubbers to reduce SO2 emissions levels generate thousands of tons of harmful sludge. Combustion of natural gas emits extremely low levels of SO2, eliminating the need for scrubbers, and reducing the amounts of sludge associated with power plants and industrial processes. Reburning – This process involves injecting natural gas into coal or oil fired boilers. The addition of natural gas to the fuel mix can result in NOx emission reductions of 50 to 70 percent, and SO2 emission reductions of 20 to 25 percent. Cogeneration – The production and use of both heat and electricity can increase the energy efficiency of electric generation systems and industrial boilers, which translates to the combustion of less fuel and the emission of fewer pollutants. Natural gas is the preferred choice for new cogeneration applications. Combined Cycle Generation – Combined-cycle generation units generate electricity and capture normally wasted heat energy, using it to generate more electricity. Like cogeneration applications, this increases energy efficiency, uses less fuel, and thus produces fewer emissions. Natural gas-fired combined-cycle generation units can be up to 60 percent energy efficient, whereas coal and oil generation units are typically only 30 to 35 percent efficient. Fuel Cells – Natural gas fuel cell technologies are in development for the generation of electricity. Fuel cells are sophisticated devices that use hydrogen to generate electricity, much like a battery. No emissions are involved in the generation of electricity from fuel cells, and natural gas, being a hydrogen rich source of fuel, can be used. Although still under development, widespread use of fuel cells could in the future significantly reduce the emissions associated with the generation of electricity. Essentially, electric generation and industrial applications that require energy, particularly for heating, use the combustion of fossil fuels for that energy. Because of its clean burning nature, the use of natural gas wherever possible, either in conjunction with other fossil fuels, or instead of them, can help to reduce the emission of harmful pollutants. According to the Congressional Research Service’s 2010 report: “Displacing Coal with Generation from Existing Natural-Gas Fired Power Plants,” if natural-gas combined cycle plants utilization were to be doubled from 42 percent capacity factor to 85 percent, then the amount of power generated would displace 19 percent of the CO2 emissions attributed to coal-fired electricity generation. Pollution from the Transportation Sector – Natural Gas Vehicles Source: EPA The transportation sector (particularly cars, trucks, and buses) is one of the greatest contributors to air pollution in the United States. Emissions from vehicles contribute to smog, low visibility, and various greenhouse gas emissions. According to the  Department of Energy  (DOE), about half of all air pollution and more than 80 percent of air pollution in cities are produced by cars and trucks in the United States. Currently, automobile manufacturers are under pressure to produce more environmentally friendly vehicles. Natural gas can be used in the transportation sector to cut down on these high levels of pollution from gasoline and diesel powered cars, trucks, and buses. According to the EPA, compared to traditional vehicles, vehicles operating on compressed natural gas have reductions in carbon monoxide emissions of 90 to 97 percent, and reductions in carbon dioxide emissions of 25 percent. Nitrogen oxide emissions can be reduced by 35 to 60 percent, and other non-methane hydrocarbon emissions could be reduced by as much as 50 to 75 percent. In addition, because of the relatively simple makeup of natural gas in comparison to traditional vehicle fuels, there are fewer toxic and carcinogenic emissions from natural gas vehicles, and virtually no particulate emissions. Thus the environmentally friendly attributes of natural gas may be used in the  transportation  sector to reduce air pollution. Natural gas vehicles represent a growing segment of the transportation sector.  According to the  Natural Gas Vehicle Coalition , the use of natural gas for vehicles doubled between 2003 and 2009.  Over 100,000 natural gas vehicles are currently on US roads.  A large portion of those vehicles are transit buses, which account for nearly 62 percent of all natural gas vehicles. Source: Department of Energy-Office of Fossil Energy Natural gas is the cleanest of the fossil fuels, and thus its many applications can serve to decrease harmful pollution levels from all sectors, particularly when used together with or replacing other fossil fuels. The natural gas industry itself is also committed to ensuring that the process of producing natural gas is as environmentally-friendly as possible. The  Natural Gas Vehicle Coalition  has more information regarding natural gas-powered vehicles.  

Fossil fuel

What contributes to the greenhouse effect at lower atmospheric levels, but in the upper atmosphere protects life on Earth?

Glossary of Climate Change Terms | Climate Change | US EPA Glossary of Climate Change Terms Glossary of Climate Change Terms Related Links A Abrupt Climate Change Sudden (on the order of decades), large changes in some major component of the climate system, with rapid, widespread effects. Adaptation Adjustment or preparation of natural or human systems to a new or changing environment which moderates harm or exploits beneficial opportunities. Adaptive Capacity The ability of a system to adjust to climate change (including climate variability and extremes) to moderate potential damages, to take advantage of opportunities, or to cope with the consequences. Aerosols Small particles or liquid droplets in the atmosphere that can absorb or reflect sunlight depending on their composition. Afforestation Planting of new forests on lands that historically have not contained forests. [1] Albedo The amount of solar radiation reflected from an object or surface, often expressed as a percentage. Alternative Energy Energy derived from nontraditional sources (e.g., compressed natural gas, solar, hydroelectric, wind). [2] Annex I Countries/Parties Group of countries included in Annex I (as amended in 1998) to the United Nations Framework Convention on Climate Change, including all the developed countries in the Organization of Economic Co-operation and Development, and economies in transition. By default, the other countries are referred to as Non-Annex I countries. Under Articles 4.2 (a) and 4.2 (b) of the Convention, Annex I countries commit themselves specifically to the aim of returning individually or jointly to their 1990 levels of greenhouse gas emissions by the year 2000. [2] Anthropogenic Made by people or resulting from human activities. Usually used in the context of emissions that are produced as a result of human activities. [3] Atmosphere The gaseous envelope surrounding the Earth. The dry atmosphere consists almost entirely of nitrogen (78.1% volume mixing ratio) and oxygen (20.9% volume mixing ratio), together with a number of trace gases, such as argon (0.93% volume mixing ratio), helium, radiatively active greenhouse gases such as carbon dioxide (0.035% volume mixing ratio), and ozone. In addition the atmosphere contains water vapor, whose amount is highly variable but typically 1% volume mixing ratio. The atmosphere also contains clouds and aerosols. [1] Atmospheric Lifetime Atmospheric lifetime is the average time that a molecule resides in the atmosphere before it is removed by chemical reaction or deposition. This can also be thought of as the time that it takes after the human-caused emission of a gas for the concentrations of that gas in the atmosphere to return to natural levels. Greenhouse gas lifetimes can range from a few years to a few thousand years. B Biofuels Gas or liquid fuel made from plant material (biomass).? Includes wood, wood waste, wood liquors, peat, railroad ties, wood sludge, spent sulfite liquors, agricultural waste, straw, tires, fish oils, tall oil, sludge waste, waste alcohol, municipal solid waste, landfill gases, other waste, and ethanol blended into motor gasoline. [4] Biogeochemical Cycle Movements through the Earth system of key chemical constituents essential to life, such as carbon, nitrogen, oxygen, and phosphorus. [3] Biomass Materials that are biological in origin, including organic material (both living and dead) from above and below ground, for example, trees, crops, grasses, tree litter, roots, and animals and animal waste. [4] Biosphere The part of the Earth system comprising all ecosystems and living organisms, in the atmosphere, on land (terrestrial biosphere) or in the oceans (marine biosphere), including derived dead organic matter, such as litter, soil organic matter and oceanic detritus. [1] Black Carbon Aerosol Black carbon (BC) is the most strongly light-absorbing component of particulate matter (PM), and is formed by the incomplete combustion of fossil fuels, biofuels, and biomass. It is emitted directly into the atmosphere in the form of fine particles (PM2.5). Borehole Any exploratory hole drilled into the Earth or ice to gather geophysical data. Climate researchers often take ice core samples, a type of borehole, to predict atmospheric composition in earlier years. See ice core . C Carbon Cycle All parts (reservoirs) and fluxes of carbon. The cycle is usually thought of as four main reservoirs of carbon interconnected by pathways of exchange. The reservoirs are the atmosphere, terrestrial biosphere (usually includes freshwater systems), oceans, and sediments (includes fossil fuels). The annual movements of carbon, the carbon exchanges between reservoirs, occur because of various chemical, physical, geological, and biological processes. The ocean contains the largest pool of carbon near the surface of the Earth, but most of that pool is not involved with rapid exchange with the atmosphere. [3] Carbon Dioxide A naturally occurring gas, and also a by-product of burning fossil fuels and biomass, as well as land-use changes and other industrial processes. It is the principal human caused greenhouse gas that affects the Earth's radiative balance. It is the reference gas against which other greenhouse gases are measured and therefore has a Global Warming Potential of 1. See climate change and global warming . [5] Carbon Dioxide Equivalent A metric measure used to compare the emissions from various greenhouse gases based upon their global warming potential (GWP). Carbon dioxide equivalents are commonly expressed as "million metric tons of carbon dioxide equivalents (MMTCO2Eq)." The carbon dioxide equivalent for a gas is derived by multiplying the tons of the gas by the associated GWP. MMTCO2Eq = (million metric tons of a gas) * (GWP of the gas) See greenhouse gas , global warming potential , metric ton . Carbon Dioxide Fertilization The enhancement of the growth of plants as a result of increased atmospheric CO2 concentration. Depending on their mechanism of photosynthesis, certain types of plants are more sensitive to changes in atmospheric CO2 concentration. [1] Carbon Footprint The total amount of greenhouse gases that are emitted into the atmosphere each year by a person, family, building, organization, or company. A persons carbon footprint includes greenhouse gas emissions from fuel that an individual burns directly, such as by heating a home or riding in a car. It also includes greenhouse gases that come from producing the goods or services that the individual uses, including emissions from power plants that make electricity, factories that make products, and landfills where trash gets sent. Carbon Sequestration Terrestrial, or biologic, carbon sequestration is the process by which trees and plants absorb carbon dioxide, release the oxygen, and store the carbon. Geologic sequestration is one step in the process of carbon capture and sequestration (CCS), and involves injecting carbon dioxide deep underground where it stays permanently.? Carbon Capture and Sequestration Carbon capture and sequestration (CCS) is a set of technologies that can greatly reduce carbon dioxide emissions from new and existing coal- and gas-fired power plants, industrial processes, and other stationary sources of carbon dioxide. It is a three-step process that includes capture of carbon dioxide from power plants or industrial sources; transport of the captured and compressed carbon dioxide (usually in pipelines); and underground injection and geologic sequestration, or permanent storage, of that carbon dioxide in rock formations that contain tiny openings or pores that trap and hold the carbon dioxide. Chlorofluorocarbons Gases covered under the 1987 Montreal Protocol and used for refrigeration, air conditioning, packaging, insulation, solvents, or aerosol propellants. Since they are not destroyed in the lower atmosphere, CFCs drift into the upper atmosphere where, given suitable conditions, they break down ozone. These gases are being replaced by other compounds: hydrochlorofluorocarbons, an interim replacement for CFCs that are also covered under the Montreal Protocol, and hydrofluorocarbons, which are covered under the Kyoto Protocol. All these substances are also greenhouse gases. See hydrochlorofluorocarbons , hydrofluorocarbons , perfluorocarbons , ozone depleting substance . [2] Climate Climate in a narrow sense is usually defined as the "average weather," or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands of years. The classical period is 3 decades, as defined by the World Meteorological Organization (WMO). These quantities are most often surface variables such as temperature, precipitation, and wind. Climate in a wider sense is the state, including a statistical description, of the climate system. See weather . [1] Climate Change Climate change refers to any significant change in the measures of climate lasting for an extended period of time. In other words, climate change includes major changes in temperature, precipitation, or wind patterns, among others, that occur over several decades or longer. Climate Feedback A process that acts to amplify or reduce direct warming or cooling effects. Climate Lag The delay that occurs in climate change as a result of some factor that changes only very slowly. For example, the effects of releasing more carbon dioxide into the atmosphere occur gradually over time because the ocean takes a long time to warm up in response to a change in radiation. See climate , climate change . Climate Model A quantitative way of representing the interactions of the atmosphere, oceans, land surface, and ice. Models can range from relatively simple to quite comprehensive. See General Circulation Model . [3] Climate Sensitivity In Intergovernmental Panel on Climate Change (IPCC) reports, equilibrium climate sensitivity refers to the equilibrium change in global mean surface temperature following a doubling of the atmospheric (equivalent) CO2 concentration. More generally, equilibrium climate sensitivity refers to the equilibrium change in surface air temperature following a unit change in radiative forcing (degrees Celsius, per watts per square meter, ?C/Wm-2). One method of evaluating the equilibrium climate sensitivity requires very long simulations with Coupled General Circulation Models (Climate model). The effective climate sensitivity is a related measure that circumvents this requirement. It is evaluated from model output for evolving non-equilibrium conditions. It is a measure of the strengths of the feedbacks at a particular time and may vary with forcing history and climate state. See climate , radiative forcing . [1] Climate System (or Earth System) The five physical components (atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere) that are responsible for the climate and its variations. [3] Coal Mine Methane Coal mine methane is the subset of coalbed methane that is released from the coal seams during the process of coal mining. For more information, visit the Coalbed Methane Outreach program site . Coalbed Methane Coalbed methane is methane contained in coal seams, and is often referred to as virgin coalbed methane, or coal seam gas. For more information, visit the Coalbed Methane Outreach program site . Co-Benefit The benefits of policies that are implemented for various reasons at the same time including climate change mitigation acknowledging that most policies designed to address greenhouse gas mitigation also have other, often at least equally important, rationales (e.g., related to objectives of development, sustainability, and equity). Concentration Amount of a chemical in a particular volume or weight of air, water, soil, or other medium. See parts per billion , parts per million . [4] Conference of the Parties The supreme body of the United Nations Framework Convention on Climate Change (UNFCCC). It comprises more than 180 nations that have ratified the Convention. Its first session was held in Berlin, Germany, in 1995 and it is expected to continue meeting on a yearly basis. The COP's role is to promote and review the implementation of the Convention. It will periodically review existing commitments in light of the Convention's objective, new scientific findings, and the effectiveness of national climate change programs. See United Nations Framework Convention on Climate Change . Coral Bleaching The process in which a coral colony, under environmental stress expels the microscopic algae (zooxanthellae) that live in symbiosis with their host organisms (polyps). The affected coral colony appears whitened. Cryosphere One of the interrelated components of the Earth's system, the cryosphere is frozen water in the form of snow, permanently frozen ground (permafrost), floating ice, and glaciers. Fluctuations in the volume of the cryosphere cause changes in ocean sea level, which directly impact the atmosphere and biosphere. [3] D Deforestation Those practices or processes that result in the conversion of forested lands for non-forest uses.? Deforestation contributes to increasing carbon dioxide concentrations for two reasons: 1) the burning or decomposition of the wood releases carbon dioxide; and 2) trees that once removed carbon dioxide from the atmosphere in the process of photosynthesis are no longer present. [4] Desertification Land degradation in arid, semi-arid, and dry sub-humid areas resulting from various factors, including climatic variations and human activities. Further, the UNCCD (The United Nations Convention to Combat Desertification) defines land degradation as a reduction or loss, in arid, semi-arid, and dry sub-humid areas, of the biological or economic productivity and complexity of rain-fed cropland, irrigated cropland, or range, pasture, forest, and woodlands resulting from land uses or from a process or combination of processes, including processes arising from human activities and habitation patterns, such as: (i) soil erosion caused by wind and/or water; (ii) deterioration of the physical, chemical and biological or economic properties of soil; and (iii) long-term loss of natural vegetation. Conversion of forest to non-forest. Dryland Farming A technique that uses soil moisture conservation and seed selection to optimize production under dry conditions. The extent to which the Earth's orbit around the Sun departs from a perfect circle. Ecosystem Any natural unit or entity including living and non-living parts that interact to produce a stable system through cyclic exchange of materials. [3] El Ni?o - Southern Oscillation (ENSO) El Ni?o, in its original sense, is a warm water current that periodically flows along the coast of Ecuador and Peru, disrupting the local fishery. This oceanic event is associated with a fluctuation of the intertropical surface pressure pattern and circulation in the Indian and Pacific Oceans, called the Southern Oscillation. This coupled atmosphere-ocean phenomenon is collectively known as El Ni?o-Southern Oscillation. During an El Ni?o event, the prevailing trade winds weaken and the equatorial countercurrent strengthens, causing warm surface waters in the Indonesian area to flow eastward to overlie the cold waters of the Peru current. This event has great impact on the wind, sea surface temperature, and precipitation patterns in the tropical Pacific. It has climatic effects throughout the Pacific region and in many other parts of the world. The opposite of an El Ni?o event is called La Ni?a. [6] Emissions The release of a substance (usually a gas when referring to the subject of climate change) into the atmosphere. Emissions Factor A unique value for scaling emissions to activity data in terms of a standard rate of emissions per unit of activity (e.g., grams of carbon dioxide emitted per barrel of fossil fuel consumed, or per pound of product produced). [4] Energy Efficiency Using less energy to provide the same service. [7] ENERGY STAR A U.S. Environmental Protection Agency voluntary program that helps businesses and individuals save money and protect our climate through superior energy efficiency. Learn more about ENERGY STAR . Enhanced Greenhouse Effect The concept that the natural greenhouse effect has been enhanced by increased atmospheric concentrations of greenhouse gases (such as CO2 and methane) emitted as a result of human activities. These added greenhouse gases cause the earth to warm. See greenhouse effect . Enteric Fermentation Livestock, especially cattle, produce methane as part of their digestion. This process is called enteric fermentation, and it represents one third of the emissions from the agriculture sector. Evaporation The process by which water changes from a liquid to a gas or vapor. [8] Evapotranspiration The combined process of evaporation from the Earth's surface and transpiration from vegetation. [1] F Feedback Mechanisms Factors which increase or amplify (positive feedback) or decrease (negative feedback) the rate of a process. An example of positive climatic feedback is the ice-albedo feedback. See climate feedback . [3] Fluorinated Gases Powerful synthetic greenhouse gases such as hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride that are emitted from a variety of industrial processes. Fluorinated gases are sometimes used as substitutes for stratospheric ozone-depleting substances (e.g., chlorofluorocarbons, hydrochlorofluorocarbons, and halons) and are often used in coolants, foaming agents, fire extinguishers, solvents, pesticides, and aerosol propellants. These gases are emitted in small quantities compared to carbon dioxide (CO2), methane (CH4), or nitrous oxide (N2O), but because they are potent greenhouse gases, they are sometimes referred to as High Global Warming Potential gases (?High GWP gases). Fluorocarbons Carbon-fluorine compounds that often contain other elements such as hydrogen, chlorine, or bromine. Common fluorocarbons include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs). See chlorofluorocarbons , hydrochlorofluorocarbons , hydrofluorocarbons , perfluorocarbons , ozone depleting substance . [3] Forcing Mechanism A process that alters the energy balance of the climate system, i.e. changes the relative balance between incoming solar radiation and outgoing infrared radiation from Earth. Such mechanisms include changes in solar irradiance, volcanic eruptions, and enhancement of the natural greenhouse effect by emissions of greenhouse gases. See radiation , infrared radiation , radiative forcing . Fossil Fuel A general term for organic materials formed from decayed plants and animals that have been converted to crude oil, coal, natural gas, or heavy oils by exposure to heat and pressure in the earth's crust over hundreds of millions of years. [4] Fuel Switching In general, this is substituting one type of fuel for another. In the climate-change discussion it is implicit that the substituted fuel produces lower carbon emissions per unit energy produced than the original fuel, e.g., natural gas for coal. G General Circulation Model (GCM) A global, three-dimensional computer model of the climate system which can be used to simulate human-induced climate change. GCMs are highly complex and they represent the effects of such factors as reflective and absorptive properties of atmospheric water vapor, greenhouse gas concentrations, clouds, annual and daily solar heating, ocean temperatures and ice boundaries. The most recent GCMs include global representations of the atmosphere, oceans, and land surface. See climate modeling . [3] Geosphere The soils, sediments, and rock layers of the Earth's crust, both continental and beneath the ocean floors. Glacier A multi-year surplus accumulation of snowfall in excess of snowmelt on land and resulting in a mass of ice at least 0.1 km2 in area that shows some evidence of movement in response to gravity. A glacier may terminate on land or in water. Glacier ice is the largest reservoir of fresh water on Earth, and second only to the oceans as the largest reservoir of total water. Glaciers are found on every continent except Australia. [3] Global Average Temperature An estimate of Earths mean surface air temperature averaged over the entire planet. Global Warming The recent and ongoing global average increase in temperature near the Earths surface. Global Warming Potential A measure of the total energy that a gas absorbs over a particular period of time (usually 100 years), compared to carbon dioxide. Greenhouse Effect Trapping and build-up of heat in the atmosphere (troposphere) near the Earths surface. Some of the heat flowing back toward space from the Earth's surface is absorbed by water vapor, carbon dioxide, ozone, and several other gases in the atmosphere and then reradiated back toward the Earths surface. If the atmospheric concentrations of these greenhouse gases rise, the average temperature of the lower atmosphere will gradually increase. See greenhouse gas , anthropogenic , climate , global warming . [4] Greenhouse Gas (GHG) H Habitat Fragmentation A process during which larger areas of habitat are broken into a number of smaller patches of smaller total area, isolated from each other by a matrix of habitats unlike the original habitat. ( Fahrig 2003 ) Halocarbons Compounds containing either chlorine, bromine or fluorine and carbon. Such compounds can act as powerful greenhouse gases in the atmosphere. The chlorine and bromine containing halocarbons are also involved in the depletion of the ozone layer. [1] Heat Island An urban area characterized by temperatures higher than those of the surrounding non-urban area. As urban areas develop, buildings, roads, and other infrastructure replace open land and vegetation. These surfaces absorb more solar energy, which can create higher temperatures in urban areas. [8] Heat Waves A prolonged period of excessive heat, often combined with excessive humidity. [9] Hydrocarbons Substances containing only hydrogen and carbon. Fossil fuels are made up of hydrocarbons. Hydrochlorofluorocarbons (HCFCs) Compounds containing hydrogen, fluorine, chlorine, and carbon atoms. Although ozone depleting substances, they are less potent at destroying stratospheric ozone than chlorofluorocarbons (CFCs). They have been introduced as temporary replacements for CFCs and are also greenhouse gases. See ozone depleting substance . Hydrofluorocarbons (HFCs) Compounds containing only hydrogen, fluorine, and carbon atoms. They were introduced as alternatives to ozone depleting substances in serving many industrial, commercial, and personal needs. HFCs are emitted as by-products of industrial processes and are also used in manufacturing. They do not significantly deplete the stratospheric ozone layer, but they are powerful greenhouse gases with global warming potentials ranging from 140 (HFC-152a) to 11,700 (HFC-23). Hydrologic Cycle The process of evaporation, vertical and horizontal transport of vapor, condensation, precipitation, and the flow of water from continents to oceans. It is a major factor in determining climate through its influence on surface vegetation, the clouds, snow and ice, and soil moisture. The hydrologic cycle is responsible for 25 to 30 percent of the mid-latitudes' heat transport from the equatorial to polar regions. [3] Hydrosphere The component of the climate system comprising liquid surface and subterranean water, such as: oceans, seas, rivers, fresh water lakes, underground water etc. [1] I Ice Core A cylindrical section of ice removed from a glacier or an ice sheet in order to study climate patterns of the past. By performing chemical analyses on the air trapped in the ice, scientists can estimate the percentage of carbon dioxide and other trace gases in the atmosphere at a given time. Analysis of the ice itself can give some indication of historic temperatures. Indirect Emissions Indirect emissions from a building, home or business are those emissions of greenhouse gases that occur as a result of the generation of electricity used in that building. These emissions are called "indirect" because the actual emissions occur at the power plant which generates the electricity, not at the building using the electricity. Industrial Revolution A period of rapid industrial growth with far-reaching social and economic consequences, beginning in England during the second half of the 18th century and spreading to Europe and later to other countries including the United States. The industrial revolution marks the beginning of a strong increase in combustion of fossil fuels and related emissions of carbon dioxide. [8] Infrared Radiation Infrared radiation consists of light whose wavelength is longer than the red color in the visible part of the spectrum, but shorter than microwave radiation. Infrared radiation can be perceived as heat. The Earths surface, the atmosphere, and clouds all emit infrared radiation, which is also known as terrestrial or long-wave radiation. In contrast, solar radiation is mainly short-wave radiation because of the temperature of the Sun. See radiation , greenhouse effect , enhanced greenhouse effect , global warming . [1] Intergovernmental Panel on climate Change (IPCC) The IPCC was established jointly by the United Nations Environment Programme and the World Meteorological Organization in 1988. The purpose of the IPCC is to assess information in the scientific and technical literature related to all significant components of the issue of climate change. The IPCC draws upon hundreds of the world's expert scientists as authors and thousands as expert reviewers. Leading experts on climate change and environmental, social, and economic sciences from some 60 nations have helped the IPCC to prepare periodic assessments of the scientific underpinnings for understanding global climate change and its consequences. With its capacity for reporting on climate change, its consequences, and the viability of adaptation and mitigation measures, the IPCC is also looked to as the official advisory body to the world's governments on the state of the science of the climate change issue. For example, the IPCC organized the development of internationally accepted methods for conducting national greenhouse gas emission inventories. Inundation The submergence of land by water, particularly in a coastal setting. [10] L Landfill Land waste disposal site in which waste is generally spread in thin layers, compacted, and covered with a fresh layer of soil each day. [4] Latitude The location north or south in reference to the equator, which is designated at zero (0) degrees. Lines of latitude are parallel to the equator and circle the globe. The North and South poles are at 90 degrees North and South latitude. [11] Least Developed Country A country with low indicators of socioeconomic development and human resources, as well as economic vulnerability, as determined by the United Nations. [12] Longwave Radiation Radiation emitted in the spectral wavelength greater than about 4 micrometers, corresponding to the radiation emitted from the Earth and atmosphere. It is sometimes referred to as 'terrestrial radiation' or 'infrared radiation,' although somewhat imprecisely. See infrared radiation . [3] Cities with populations over 10 million. Methane (CH4) A hydrocarbon that is a greenhouse gas with a global warming potential most recently estimated at 25 times that of carbon dioxide (CO2). Methane is produced through anaerobic (without oxygen) decomposition of waste in landfills, animal digestion, decomposition of animal wastes, production and distribution of natural gas and petroleum, coal production, and incomplete fossil fuel combustion. The GWP is from the IPCC's Fourth Assessment Report (AR4). For more information visit EPA's Methane page . Metric Ton Common international measurement for the quantity of greenhouse gas emissions. A metric ton is equal to 2205 lbs or 1.1 short tons. See short ton . [4] Mitigation A human intervention to reduce the human impact on the climate system; it includes strategies to reduce greenhouse gas sources and emissions and enhancing greenhouse gas sinks. [8] Mount Pinatubo A volcano in the Philippine Islands that erupted in 1991. The eruption of Mount Pinatubo ejected enough particulate and sulfate aerosol matter into the atmosphere to block some of the incoming solar radiation from reaching Earth's atmosphere. This effectively cooled the planet from 1992 to 1994, masking the warming that had been occurring for most of the 1980s and 1990s. [3] Municipal Solid Waste (MSW) Residential solid waste and some non-hazardous commercial, institutional, and industrial wastes. This material is generally sent to municipal landfills for disposal. See landfill . N Natural Gas Underground deposits of gases consisting of 50 to 90 percent methane (CH4) and small amounts of heavier gaseous hydrocarbon compounds such as propane (C3H8) and butane (C4H10). Natural Variability Variations in the mean state and other statistics (such as standard deviations or statistics of extremes) of the climate on all time and space scales beyond that of individual weather events. Natural variations in climate over time are caused by internal processes of the climate system, such as El Ni?o, as well as changes in external influences, such as volcanic activity and variations in the output of the sun. [8] [13] Nitrogen Cycle The natural circulation of nitrogen among the atmosphere, plants, animals, and microorganisms that live in soil and water. Nitrogen takes on a variety of chemical forms throughout the nitrogen cycle, including nitrous oxide (N2O) and nitrogen oxides (NOx). Nitrogen Oxides (NOx) Gases consisting of one molecule of nitrogen and varying numbers of oxygen molecules. Nitrogen oxides are produced in the emissions of vehicle exhausts and from power stations. In the atmosphere, nitrogen oxides can contribute to formation of photochemical ozone (smog), can impair visibility, and have health consequences; they are thus considered pollutants. [3] Nitrous Oxide (N2O) A powerful greenhouse gas with a global warming potential of 298 times that of carbon dioxide (CO2). Major sources of nitrous oxide include soil cultivation practices, especially the use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass burning. The GWP is from the IPCC's Fourth Assessment Report (AR4). [3] Natural emissions of N2O are mainly from bacteria breaking down nitrogen in soils and the oceans. Nitrous oxide is mainly removed from the atmosphere through destruction in the stratosphere by ultraviolet radiation and associated chemical reactions, but it can also be consumed by certain types of bacteria in soils. Non-Methane Volatile Organic Compounds (NMVOCs) Organic compounds, other than methane, that participate in atmospheric photochemical reactions. O Ocean Acidification Increased concentrations of carbon dioxide in sea water causing a measurable increase in acidity (i.e., a reduction in ocean pH). This may lead to reduced calcification rates of calcifying organisms such as corals, mollusks, algae and crustaceans. [8] Oxidize To chemically transform a substance by combining it with oxygen. [4] Ozone Ozone, the triatomic form of oxygen (O3), is a gaseous atmospheric constituent. In the troposphere, it is created by photochemical reactions involving gases resulting both from natural sources and from human activities (photochemical smog). In high concentrations, tropospheric ozone can be harmful to a wide range of living organisms. Tropospheric ozone acts as a greenhouse gas. In the stratosphere, ozone is created by the interaction between solar ultraviolet radiation and molecular oxygen (O2). Stratospheric ozone plays a decisive role in the stratospheric radiative balance. Depletion of stratospheric ozone, due to chemical reactions that may be enhanced by climate change, results in an increased ground-level flux of ultraviolet (UV-) B radiation. See atmosphere , ultraviolet radiation . [6] Ozone Depleting Substance (ODS) A family of man-made compounds that includes, but are not limited to, chlorofluorocarbons (CFCs), bromofluorocarbons (halons), methyl chloroform, carbon tetrachloride, methyl bromide, and hydrochlorofluorocarbons (HCFCs). These compounds have been shown to deplete stratospheric ozone, and therefore are typically referred to as ODSs. See ozone . [4] Ozone Layer The layer of ozone that begins approximately 15 km above Earth and thins to an almost negligible amount at about 50 km, shields the Earth from harmful ultraviolet radiation from the sun. The highest natural concentration of ozone (approximately 10 parts per million by volume) occurs in the stratosphere at approximately 25 km above Earth. The stratospheric ozone concentration changes throughout the year as stratospheric circulation changes with the seasons. Natural events such as volcanoes and solar flares can produce changes in ozone concentration, but man-made changes are of the greatest concern. See stratosphere , ultraviolet radiation . [3] Ozone Precursors Chemical compounds, such as carbon monoxide, methane, non-methane hydrocarbons, and nitrogen oxides, which in the presence of solar radiation react with other chemical compounds to form ozone, mainly in the troposphere. See troposphere . [4] P Particulate matter(PM) Very small pieces of solid or liquid matter such as particles of soot, dust, fumes, mists or aerosols. The physical characteristics of particles, and how they combine with other particles, are part of the feedback mechanisms of the atmosphere. See aerosol , sulfate aerosols . [3] Parts Per Billion (ppb) Number of parts of a chemical found in one billion parts of a particular gas, liquid, or solid mixture. See concentration . Parts Per Million by Volume (ppmv) Number of parts of a chemical found in one million parts of a particular gas, liquid, or solid. See concentration . Parts Per Trillion (ppt) Number of parts of a chemical found in one trillion parts of a particular gas, liquid or solid. See concentration . Perfluorocarbons (PFCs) A group of chemicals composed of carbon and fluorine only. These chemicals (predominantly CF4 and C2F6) were introduced as alternatives, along with hydrofluorocarbons, to the ozone depleting substances. In addition, PFCs are emitted as by-products of industrial processes and are also used in manufacturing. PFCs do not harm the stratospheric ozone layer, but they are powerful greenhouse gases: CF4 has a global warming potential (GWP) of 7,390 and C2F6 has a GWP of 12,200. The GWP is from the IPCC's Fourth Assessment Report (AR4). These chemicals are predominantly human-made, though there is a small natural source of CF4. See ozone depleting substance . Permafrost Perennially (continually) frozen ground that occurs where the temperature remains below 0?C for several years. [8] Phenology The timing of natural events, such as flower blooms and animal migration, which is influenced by changes in climate. Phenology is the study of such important seasonal events. Phenological events are influenced by a combination of climate factors, including light, temperature, rainfall, and humidity. Photosynthesis The process by which plants take CO2 from the air (or bicarbonate in water) to build carbohydrates, releasing O2 in the process. There are several pathways of photosynthesis with different responses to atmospheric CO2 concentrations. See carbon sequestration , carbon dioxide fertilization . [1] Precession The wobble over thousands of years of the tilt of the Earths axis with respect to the plane of the solar system. [3] R Radiation Energy transfer in the form of electromagnetic waves or particles that release energy when absorbed by an object. See ultraviolet radiation , infrared radiation , solar radiation , longwave radiation . [3] Radiative Forcing A measure of the influence of a particular factor (e.g. greenhouse gas (GHG), aerosol, or land use change) on the net change in the Earths energy balance. Recycling Collecting and reprocessing a resource so it can be used again. An example is collecting aluminum cans, melting them down, and using the aluminum to make new cans or other aluminum products. [4] Reflectivity The ability of a surface material to reflect sunlight including the visible, infrared, and ultraviolet wavelengths. [14] Reforestation Planting of forests on lands that have previously contained forests but that have been converted to some other use. [1] Relative Sea Level Rise The increase in ocean water levels at a specific location, taking into account both global sea level rise and local factors, such as local subsidence and uplift. Relative sea level rise is measured with respect to a specified vertical datum relative to the land, which may also be changing elevation over time. [10] Renewable Energy Energy resources that are naturally replenishing such as biomass, hydro, geothermal, solar, wind, ocean thermal, wave action, and tidal action. [5] Residence Time The average time spent in a reservoir by an individual atom or molecule. With respect to greenhouse gases, residence time refers to how long on average a particular molecule remains in the atmosphere. For most gases other than methane and carbon dioxide, the residence time is approximately equal to the atmospheric lifetime . [4] Resilience A capability to anticipate, prepare for, respond to, and recover from significant multi-hazard threats with minimum damage to social well-being, the economy, and the environment. Respiration The process whereby living organisms convert organic matter to CO2, releasing energy and consuming O2. [1] S Salt Water Intrusion Displacement of fresh or ground water by the advance of salt water due to its greater density, usually in coastal and estuarine areas. [10] Scenarios A plausible and often simplified description of how the future may develop based on a coherent and internally consistent set of assumptions about driving forces and key relationships. Sea Surface Temperature The temperature in the top several feet of the ocean, measured by ships, buoys and drifters. [13] Sensitivity The degree to which a system is affected, either adversely or beneficially, by climate variability or change. The effect may be direct (e.g., a change in crop yield in response to a change in the mean, range or variability of temperature) or indirect (e.g., damages caused by an increase in the frequency of coastal flooding due to sea level rise). [8] Short Ton Common measurement for a ton in the United States. A short ton is equal to 2,000 lbs or 0.907 metric tons. See metric ton . Sink Any process, activity or mechanism which removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas or aerosol from the atmosphere. [1] Snowpack A seasonal accumulation of slow-melting snow. [8] Soil Carbon A major component of the terrestrial biosphere pool in the carbon cycle. The amount of carbon in the soil is a function of the historical vegetative cover and productivity, which in turn is dependent in part upon climatic variables. [4] Solar Radiation Radiation emitted by the Sun. It is also referred to as short-wave radiation. Solar radiation has a distinctive range of wavelengths (spectrum) determined by the temperature of the Sun. See ultraviolet radiation , infrared radiation , radiation . [1] Storm Surge An abnormal rise in sea level accompanying a hurricane or other intense storm, whose height is the difference between the observed level of the sea surface and the level that would have occurred in the absence of the cyclone. [10] Stratosphere Region of the atmosphere between the troposphere and mesosphere, having a lower boundary of approximately 8 km at the poles to 15 km at the equator and an upper boundary of approximately 50 km. Depending upon latitude and season, the temperature in the lower stratosphere can increase, be isothermal, or even decrease with altitude, but the temperature in the upper stratosphere generally increases with height due to absorption of solar radiation by ozone. [3] Stratospheric Ozone See ozone layer . Streamflow The volume of water that moves over a designated point over a fixed period of time. It is often expressed as cubic feet per second (ft3/sec). [6] Subsiding/Subsidence The downward settling of the Earth's crust relative to its surroundings. [10] Sulfate Aerosols Particulate matter that consists of compounds of sulfur formed by the interaction of sulfur dioxide and sulfur trioxide with other compounds in the atmosphere. Sulfate aerosols are injected into the atmosphere from the combustion of fossil fuels and the eruption of volcanoes like Mt. Pinatubo. Sulfate aerosols can lower the Earth's temperature by reflecting away solar radiation (negative radiative forcing). General Circulation Models which incorporate the effects of sulfate aerosols more accurately predict global temperature variations. See particulate matter , aerosol , General Circulation Models . [3] Sulfur Hexafluoride (SF6) A colorless gas soluble in alcohol and ether, slightly soluble in water. A very powerful greenhouse gas used primarily in electrical transmission and distribution systems and as a dielectric in electronics. The global warming potential of SF6 is 22,800. This GWP is from the IPCC's Fourth Assessment Report (AR4). See Global Warming Potential . [4] 1 trillion (1012) grams = 1 million (106) metric tons. Thermal Expansion The increase in volume (and decrease in density) that results from warming water. A warming of the ocean leads to an expansion of the ocean volume, which leads to an increase in sea level. [8] Thermohaline Circulation Large-scale density-driven circulation in the ocean, caused by differences in temperature and salinity. In the North Atlantic the thermohaline circulation consists of warm surface water flowing northward and cold deep water flowing southward, resulting in a net poleward transport of heat. The surface water sinks in highly restricted sinking regions located in high latitudes. [1] Trace Gas Any one of the less common gases found in the Earth's atmosphere. Nitrogen, oxygen, and argon make up more than 99 percent of the Earth's atmosphere. Other gases, such as carbon dioxide, water vapor, methane, oxides of nitrogen, ozone, and ammonia, are considered trace gases. Although relatively unimportant in terms of their absolute volume, they have significant effects on the Earth's weather and climate. [3] Troposphere The lowest part of the atmosphere from the surface to about 10 km in altitude in mid-latitudes (ranging from 9 km in high latitudes to 16 km in the tropics on average) where clouds and "weather" phenomena occur. In the troposphere temperatures generally decrease with height. See ozone precursors , stratosphere , atmosphere . [1] Tropospheric Ozone (O3) See ozone precursors . Tundra A treeless, level, or gently undulating plain characteristic of the Arctic and sub-Arctic regions characterized by low temperatures and short growing seasons. [8] U Ultraviolet Radiation (UV) The energy range just beyond the violet end of the visible spectrum. Although ultraviolet radiation constitutes only about 5 percent of the total energy emitted from the sun, it is the major energy source for the stratosphere and mesosphere, playing a dominant role in both energy balance and chemical composition. Most ultraviolet radiation is blocked by Earth's atmosphere, but some solar ultraviolet penetrates and aids in plant photosynthesis and helps produce vitamin D in humans. Too much ultraviolet radiation can burn the skin, cause skin cancer and cataracts, and damage vegetation. [3] United Nations Framework Convention on Climate Change (UNFCCC) The Convention on Climate Change sets an overall framework for intergovernmental efforts to tackle the challenge posed by climate change. It recognizes that the climate system is a shared resource whose stability can be affected by industrial and other emissions of carbon dioxide and other greenhouse gases. The Convention enjoys near universal membership, with 189 countries having ratified. Under the Convention, governments: gather and share information on greenhouse gas emissions, national policies and best practices launch national strategies for addressing greenhouse gas emissions and adapting to expected impacts, including the provision of financial and technological support to developing countries cooperate in preparing for adaptation to the impacts of climate change The Convention entered into force on 21 March 1994. [4] V Vulnerability The degree to which a system is susceptible to, or unable to cope with, adverse effects of climate change, including climate variability and extremes. Vulnerability is a function of the character, magnitude, and rate of climate variation to which a system is exposed; its sensitivity; and its adaptive capacity. [15] Water that has been used and contains dissolved or suspended waste materials. [4] Water Vapor The most abundant greenhouse gas, it is the water present in the atmosphere in gaseous form. Water vapor is an important part of the natural greenhouse effect. While humans are not significantly increasing its concentration through direct emissions, it contributes to the enhanced greenhouse effect because the warming influence of greenhouse gases leads to a positive water vapor feedback. In addition to its role as a natural greenhouse gas, water vapor also affects the temperature of the planet because clouds form when excess water vapor in the atmosphere condenses to form ice and water droplets and precipitation. See greenhouse gas . [3] Weather Atmospheric condition at any given time or place. It is measured in terms of such things as wind, temperature, humidity, atmospheric pressure, cloudiness, and precipitation. In most places, weather can change from hour-to-hour, day-to-day, and season-to-season. Climate in a narrow sense is usually defined as the "average weather", or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years. The classical period is 30 years, as defined by the World Meteorological Organization (WMO). These quantities are most often surface variables such as temperature, precipitation, and wind. Climate in a wider sense is the state, including a statistical description, of the climate system. A simple way of remembering the difference is that climate is what you expect (e.g. cold winters) and 'weather' is what you get (e.g. a blizzard). See climate . #

i don't know

What is the name of the process by which substances are washed out of the soil?

Ch02 Some countries poison soils Why should the leaders of countries today commit their governments and their people to the hard work and expense of a national programme of soil conservation? The answer is that soil takes many years to create, but it can be destroyed in almost no time at all. With the loss of soil goes man's ability to grow food crops and graze animals, to produce fibre and forests. It is not enough to describe the soil as a country's greatest source of wealth; it is more than that; it is a country's life. And in one country after another today, the soil is washing or blowing away.   Soil is a complex mixture Soil covers most of the land surface of the earth in a thin layer, ranging from a few centimetres to several metres deep. It is composed of rock and mineral particles of many sizes mixed with water, air, and living things, both plant and animal, and their remains. As man measures time, soil formation is extremely slow. Where the climate is moist and warm, it takes thousands of years to form just a few centimetres of soil. In cold or dry climates, it takes even longer, or soil may not form at all. While soil is technically a renewable resource, its slow rate of formation makes it practically irreplaceable. Soil is a dynamic mixture, forever changing as water comes and goes and plants and animals live and die. Wind, water, ice, and gravity move soil particles about, sometimes slowly, sometimes rapidly. But even though a soil changes, the layers of soil stay much the same during one human lifetime unless they are moved or scraped, or ploughed by man.   Soil teems with life All soil is full of life, and good soils are teeming with it. Plants and animals help keep the soil fertile. Plant roots tunnel through the soil and break it up, and decaying plants form humus. Burrowing animals mix the soil; the excrete of animals contribute nutrients and improve soil structure. Besides the soil's more obvious inhabitants, which include rodents, insects, mites, slugs and snails, spiders, and earthworms, there are countless microscopic residents, some helpful to man and his crops, some harmful. Good soils seem to hold the greatest populations of bacteria. Almost without exception, bacteria are involved in basic enzyme transformations that make possible the growth of higher plants, including our food crops. From man's point of view, bacteria may well be the most valuable of the life forms in soil. Chemical reactions occur in the soil as a result of exchange of positive ions, or cations. More exchanges take place in clay soils than in any other type. These chemical reactions are also essential to plant growth and development and are a good index of soil fertility.   Only a fraction of land is arable Man's chief interest in soil is for agriculture, but not all soils are suitable for farming. The total land area of the world exceeds 13 billion hectares, but less than half can be used for agriculture, including grazing. A much smaller fraction - about 1.4 billion hectares - is presently suitable for growing crops. The rest of the land is either too wet or too dry, too shallow or too rocky. Some is toxic or deficient in the nutrients that plants require and some is permanently frozen . Europe, Central America, and North America have the highest proportion of soils suitable for farming, although a number of the more developed countries seem intent on paving over much of their best farmland with roads and buildings. The lowest proportions of arable soils are in North and Central Asia, South America, and Australia. The single most serious drawback to farming additional land is lack of water.   Erosion destroyed civilizations Civilizations began where farming was most productive. When farm productivity declined, usually as a result of soil mismanagement, civilizations also declined - and occasionally vanished entirely. Of the three requisites for a thriving civilization: fertile soil, a dependable water supply and relatively level land with reasonable rainfall which would not cause erosion, it is likely that the third factor was most important, and evidence is mounting that soil degradation has toppled civilizations as surely as military conquest. In countries bordering the Mediterranean, deforestation of slopes and the erosion that followed has created man-made deserts of once productive land. Ancient Romans ate well on produce from North African regions that are desert today. A recent study of the collapse in Guatemala around 900 AD of the 1700 year-old Mayan civilization suggests that it fell apart for similar reasons. Researchers have found evidence that population growth among the Mayans was followed by cutting trees on mountainsides to expand areas for farming. The soil erosion that resulted from growing crops on steeper and steeper slopes lowered soil productivity - both in the hills and in the valleys - to a point where the populations could no longer survive in that area. Today only empty ruins remain. The same process of soil degradation which destroyed civilizations in the past are still at work today. Firstly, billions of tons of soil are being physically lost each year through accelerated erosion from the action of water and wind and by undesirable changes in soil structure. Secondly, many soils are being degraded by increases in their salt content, by waterlogging, or by pollution through the indiscriminate application of chemical and industrial wastes. Thirdly, many soils are losing the minerals and organic matter that make them fertile, and in most cases, these materials are not being replaced nearly as fast as they are being depleted. Finally, millions of hectares of good farmland are being lost each year to nonfarm purposes; they are being flooded for reservoirs or paved over for highways, airports, and parking lots. The result of all this mismanagement will be less productive agricultural land at a time when world population is growing and expectations are rising among people everywhere for a better life.   The worst threat is erosion The most serious form of soil degradation is from accelerated erosion. Erosion is the washing or blowing away of surface soil, sometimes down to bedrock. While some erosion takes place without the influence of man, the soil is lost so slowly that it is usually replaced through natural processes of decay and regeneration. Soil loss and soil creation of new soil stay in balance. What keeps soil in a natural state from eroding is vegetation. Undisturbed by man, soil is usually covered by a canopy of shrubs and trees, by dead and decaying leaves or by a thick mat of grass. Whatever the vegetation, it protects the soil when the rain falls or the wind blows. The leaves and branches of trees and the cushion of grass absorb the force of raindrops, and root systems of plants hold the soil together. Even in drought, the roots of native grasses, which extend several metres into the ground, help tie down the soil and keep it from blowing away. With its covering of vegetation stripped away, however, soil is as vulnerable to damage as a tortoise without its shell. Whether the plant cover is disturbed by cultivation, grazing, burning, or bulldozing, once the soil is laid bare to the erosive action of wind and water, the slow rate of natural erosion is greatly accelerated. Losses of soil take place much faster than new soil can be created, and a kind of deficit spending begins with the topsoil.   Bad farming encourages soil loss Unfortunately, many bad farming and forestry operations encourage erosion. Erosion accelerates when sloping land is ploughed and when grass is removed from semi-arid land to begin dryland farming. It accelerates when cattle, sheep and goats are allowed to overgraze and when hillside forests are felled or cut indiscriminately. While there are isolated instances of deserts being reclaimed by irrigation or of new forests being planted, man, in the majority of instances, degrades the soil when he begins agricultural operations. And his highest risk operations are conducted on cropland, which is particularly prone to the hazards of soil erosion, especially if farming systems leave the land bare for part of the year, exposed to wind and water. The mechanics of soil erosion are fairly well understood today by conservationists and by many farmers. Erosion from water proceeds in three steps: (1) soil particles are loosened by the bomb-like impact of raindrops or the scouring action of runoff water; (2 ) the detached particles are moved down the slopes by flowing water; and (3) the soil particles are deposited at new locations, either on top of other soil at the bottom of the slope or in ponds or waterways. The soil washed downhill is usually the most fertile, containing most of the nutrients and organic matter required for normal plant growth. All other things being equal, the steeper the slope, the greater the soil erosion. Erosion is also more severe on long slopes than on short ones; the velocity of the water flow increases on long, unobstructed downhill stretches. Soil loss may be half again as great when the slope length is doubled. Also significant is the shape of the slope. A convex or bulging slope loses more soil than a uniform slope. A concave or dish-shaped slope loses less. Many erodible soils also seal off the surface pores of the soil as they travel downhill with the runoff water. This action further decreases the amount of water that can be absorbed by the soil and increases the water's velocity, causing even more erosion.   Rainfall energy varies Still another factor in soil erosion from water is the erosivity of the rain its intensity and duration. In many parts of Europe, where rains are relatively gentle, erosion is rarely severe. In most tropical countries and in parts of the United States, however, rains are much more intense and occasionally torrential. Much more rain falls per hour, and as rainfall intensity increases, the size of individual raindrops also increases. A tropical raindrop strikes unprotected soil with more force than raindrops in Europe, dislodging more soil. The flow of water down a slope is also greater, and the net result is more soil eroded and moved downhill. Time is also a factor in erosion. A hard continuous rain will dislodge more soil than several brief showers, particularly when the soils are relatively impermeable. Season is a factor, too. The monsoon rain in the Indian subcontinent keeps farmers from planting many soils, and the bare fields are subject to serious soil erosion. In the Corn Belt of the USA, spring rains are usually the heaviest of the year, striking the soil before seed can be planted or when seedlings can be easily washed out.   Why some soils erode easily Another factor in water erosion is the character of the soil itself. Some soils tend to erode easily from the action of rain and runoff; others are remarkably resistant, even in heavy downpours. The susceptibility of different kinds of soils to erosion under cultivation varies widely. Perhaps the most important factor is the relative ability of the soil to absorb rainfall rapidly. Certain soils of the tropics absorb rainfall so rapidly that there is little erosion, even on steep slopes. On the other hand, some erodible tropical soils require very little energy to disintegrate under the impact of raindrops. One reason for the instability of many tropical soils is the predominance of coarse particles, which are easily detached by the pounding action of the rain. The finer particles are then washed off the field with the runoff water. A number of the world's most erodible soils have a topsoil layer that is from 10 to 40 centimetres deep, underlain by a layer of subsoil that is barely permeable by water. After the upper layer of soil becomes saturated by rain, it begins to flow downhill, even on gentle slopes. What makes one soil subject to erosion and another relatively impervious is a complex matter. There is no single cause for erodibility. But without question, the organic matter in the soil - decayed and decaying plant and animal matter - helps protect it from washing.   Organic soils soak up water Organic matter in soil can absorb and store much more water than can inorganic fractions. It acts like a sponge, taking up water and releasing it as required by plants. It also helps bind soil particles into larger aggregates, or crumbs. Soils with this kind of structure are very resistant to erosion. Conversely, nearly all soils containing little or no organic matter are very susceptible to erosion. Besides absorbing water readily, a good cropland soil should be able to dry out or warm up quickly when the rain is over. It should hold enough moisture to supply the needs of a crop between rains, yet permit water to pass through the soil. A good soil will not stay too wet or too dry. Another factor in erosion from water is the crop that is being grown in the soil and the way that crop is being managed. Sloping land planted with trees or grass will erode less than the same land planted with maize or soybeans. Maize planted on terraces will suffer less erosion than maize planted in rows that march straight down the slope, inviting runoff water to rush downhill between the rows. There are other, less obvious relationships between soil erosion and crop selection and management. Many soils can be planted with maize without much erosion risk if the maize crop is rotated with legumes and small grains. If maize is planted year after year, however, soil losses begin to mount. The basic factors then that contribute to soil erosion from water in rainfed agriculture appear to be similar the world over. For any particular plot of land, they include the degree of slope, the length of slope and its shape, the erosivity of the rain and inherent erodibility of the soil, and the mismanagement of the land by the farmer or herdsman. Much more remains to be learned, however, about the management of specific soils in tropical and subtropical areas to reduce the impact of these erosion factors.   "Invisible" erosion takes toll There are several types of man-made erosion, all but the first clearly recognizable as trouble. The first - and most insidious - is sheet erosion, which is the more or less even removal of a thin layer or "sheet" of soil from a sloping field. It is insidious because the amount of soil seen to be removed is usually so small in any given year that a farmer often fails to notice that erosion is occurring. Occasionally he becomes aware of sheet erosion only after he notices that a formerly buried object - a rock, the lower portion of a fence post, or root of a tree - is suddenly exposed. However, sheet erosion removes great quantities of topsoil. Even a very thin layer of soil, only slightly thicker than a piece of wrapping paper, when transported down a slope, can weigh several tons per hectare. It does not take many years or many rainstorms for losses from sheet erosion to become significant. A second variety of erosion is more evident to the farmer, and that is "rill" erosion. Sheet erosion occurs mainly when the surface of a field is smooth and the slope is uniform. But the surface of most fields is irregular. There are apt to be low places and high places; rough places and smooth places; and various kinds of soils, even in a 5 hectare field. When it rains, the soil erodes unevenly, and rainwater accumulates and flows into depressions, taking the path of least resistance as it moves downhill. The surface flow moves into small channels, or rills, which are cut into the soil several inches deep. Rills are small enough to be erased easily with normal tillage methods, but left alone, they can become progressively wider and deeper until they cut into the subsoil and form gullies.   Gullies climb uphill A gully always begins at the lower end of a slope and eats its way back uphill, where it creates a gully head with a sudden or steep fall. Eventually it will work its way to the top of the slope, growing deeper and wider with each rainstorm. The splash action of the falling water at the head of the gully undermines the lower part of the excavated earth wall, causing collapse of even more of the soil. Unlike a rill, a gully cannot be smoothed out with a plough or a disk. While a new gully may be narrow and 2 or 3 feet deep, older gullies can grow to enormous size - 40 feet deep and as much as 100 feet wide. The formation of gullies is frequently encouraged by man and his animals. Many gullies begin with stock trails, farm roads, and other regular or irregular pathways on sloping land. Some large gullies develop tributaries, particularly at points where livestock habitually enter and leave a ravine. A recent study of the development in the 19th century of severe gully erosion at the head of a creek in New South Wales, Australia, revealed that it began during periods of cultivation and overgrazing and, not incidentally, during the years of the highest rabbit populations. These animals, like many insects, can speed up destruction of vegetation and soil erosion. Gullies are relentless destroyers of good farmland. They can cut up a field into small, odd-shaped parcels and restrict the free movement of animals and farm machinery. They are a menace to livestock; calves and other animals frequently fall in and are unable to escape. Gullies can also threaten nearby barns and other buildings, which may have to be moved before they are undermined. The stabilization and repair of gullies is the most costly of all erosion control work. Stopping a gully often requires extensive earthmoving and construction of dams or other measures. On the other hand, the formation of gullies can usually be prevented through good land use.   How erosion reduces yields For the farmer, and for the consumer as well, the worst thing about soil erosion is that it reduces crop yields and increases the costs of growing food and fibre. Firstly, erosion reduces the capacity of the soil to hold water and make that water available to plants. This subjects crops to more frequent and severe water stress. Secondly, erosion contributes to losses of plant nutrients, which wash away with the soil particles. Because subsoils generally contain fewer nutrients than topsoils, more fertilizer is needed to maintain crop yields. This, in turn, increases production costs. Moreover, the addition of fertilizer alone cannot compensate for all the nutrients lost when topsoil erodes. Thirdly, erosion reduces yields by degrading soil structure, increasing soil erodibility, surface sealing and crusting. Water infiltration is reduced, and seedlings have a harder time breaking through the soil crust. Fourthly, erosion reduces productivity because it does not remove topsoil uniformly over the surface of a field. Typically, parts of an eroded field still have several inches of topsoil left; other parts may be eroded down to the subsoil. This makes it practically impossible for a farmer to manage the field properly, to apply fertilizers and chemicals uniformly and obtain uniform results. He is also unable to time his planting, since an eroded part of the field may be too wet when the rest of the field is dry and ready.   Eroding soil affects water resources Damage from water erosion is not limited to the loss of productivity on the land where it occurs. The bulk of eroded soil from a hillside comes to rest a short distance away, at the foot of the slope or on a nearby flood plain, where it may bury crops or lower the fertility of bottomlands. A portion of the eroded soil is deposited in local drainage or irrigation ditches or runs into ponds, reservoirs, or tributary streams and rivers. Wherever it is deposited, it is unwelcome. Sediment-filled ditches have to be dug out again; ponds, lakes, and reservoirs either have to be dredged out or abandoned. Locally, sediment is an expensive nuisance . Damage also occurs downstream, sometimes at great distances from the farmland that originally contributed the sediment. Carried along by a river, sediment is dropped out as the waterway reaches flatter, lower reaches. The sediment deposits raise the level of the riverbed and reduce the capacity of the channel to hold water. Riverbanks overtop more frequently, and valuable bottomland, often extremely productive, is damaged by flooding.   Windblown soil endangers land Soil blown by wind is second only to erosion by water as a destroyer of agricultural land. It occurs most often in arid and semi-arid regions, but it can also happen in areas of seasonal rainfall. Wind erosion is a persistent hazard in the Sahara and Kalahari deserts of Africa; in Central Asia, particularly in the Steppes of the Soviet Union; in central Australia, and in the Great Plains of the United States, well known as the Dust Bowl of the 1930s. Windborne topsoil may be transported over very long distances and, like soil eroded by water, it is usually deposited where it is not wanted. Farmlands, fences, machinery, and buildings can be severely damaged by wind erosion, and sometimes they can be buried completely. Costs of rehabilitation can run so high that the land is abandoned. The following conditions set the stage for erosion from wind: the soil is loose, dry, and finely divided; the soil surface is relatively smooth and plant cover is sparse; and the field is sufficiently large and the wind strong enough to initiate air movement. When the wind blows hard over a smooth field, at some point near the surface the wind velocity will be zero. Above that point there is a layer of smooth airflow, and above that, an area of turbulence. It is this turbulent airflow which causes soil particles to begin to move. Once movement is begun, the soil particles themselves abrade the soil surface and magnify the effect of the wind. In a severe storm, dust clouds rise hundreds of metres into the air, and on occasion travel hundreds, even thousands, of kilometres before the eroded soil falls on the land or into the ocean. The soil particles that are blown away are usually the finer ones; the coarse and heavy sand remains. If this process continues for long, the productivity of the damaged land gradually decreases. The physical causes of wind erosion are clearly different from those which allow soil to wash, except for one factor that is constant in all man-made soil erosion - the absence of vegetation to hold and cover the soil. It is when trees, bushes, grasses, and other plants are removed from land that erosion occurs.   Poor management degrades soil Soil does not have to be washed or blown away for its productivity to be lowered. Through improper soil and water management, a soil's properties may be altered so that its fertility is seriously reduced or lost for good. Excessive cultivation, for example, can wreck the structure of some soils so that they are no longer capable of holding enough moisture for growing plants. Salinization, or the accumulation of salts in the topsoil, can also have a deletrious effect on soil productivity and crop yields. In extreme cases, damage from salinization is so great that it is technically unfeasible or totally uneconomic to reverse the process. In general, salinization is caused by water and dissolved salts moving up in the soil through capillary action. While salinization is occasionally the result of natural soil-forming processes, it occurs most frequently in irrigated soils, where it is worsened by the high salt content of irrigation water. Salt-affected soils are found on every continent and nearly 7 percent of the land area of the world is affected. Salinization is a serious problem in Australia, the Soviet Union, and the United States, and it is critical in countries of north Africa and the Near East.   Soils degrade through waterlogging and loss of nutrients Waterlogged soils also deter agriculture in many countries, even in parts of the world where an excess of water is not usually thought of as a problem. Waterlogging interferes with agriculture in many countries; in Egypt, for example, where about one-third of the Nile Delta has a water table only 80 centimetres below the surface. Other countries with waterlogging from high water tables and runoff include Iran, Iraq, Somalia, parts of Syria, and Pakistan. Soil can also become degraded through loss of nutrients - chiefly nitrogen, phosphorus, and potassium - if these are not replenished to maintain soil fertility. Besides being lost through erosion, nutrients are also depleted by the crops themselves, particularly if the same crops are grown on the same land year after year. And in the humid tropics, many nutrients are leached during the intense rainstorms, especially on unprotected land. Without question, farming all over the world is removing more nutrients from the soil than are being put back. Soil compaction is still another destroyer of the soil. Sometimes it results from repeated passes over the same field with heavy machinery, particularly when the field is wet. It can also result from the hooves of grazing animals pounding down the soil too often in the same area, as they do around the only waterhole for miles. Compaction is not easy to correct.   Some countries poison soils Other forms of soil degradation occur in the more developed countries, but are rarely of concern to the developing ones - so far. Farmland is not only paved over by urbanization but is occasionally poisoned with chemicals. While pesticides and even fertilizers are sometimes suspected of causing soil impairment, the damage in most cases is not permanent. However, some apple orchards sprayed with arsenic compounds in the 1930s were reported as still unproductive 30 years later. In recent years, there has been a general movement in many developed countries against using the more persistent insecticides, including a chemical group that includes DDT and chlordane. Radioactive fallout, and Strontium 90 in particular, also caused public concern during the period of nuclear bomb tests. Today a more serious problem in several highly industrialized countries is the indiscriminate dumping of chemical wastes, some of which are extremely toxic to plants, animals, and man, and the growing use of sewage sludge, some of which contains dangerous heavy metals which can be taken up by plants. For a developing nation, however, such problems are at present insignificant compared with the growing threat to their agricultural productivity from erosion, salinization, waterlogging, and general loss of fertility.

Leaching

Who was director of the environmental pressure group Friends of the Earth 1984 - 90?

What is leaching? definition and meaning - BusinessDictionary.com chemical oxygen... Use 'leaching' in a Sentence The corporation's lawyers argued that its toxic waste disposal practices were safe and environmentally friendly but conservationists produced evidence that clearly showed dangerous chemicals leaching out from contaminated soil beds. 18 people found this helpful In Chemistry class today, we went over leaching which made me and my friend bored because we hated everything about it. 16 people found this helpful When running an industrial plant you must be able to be good at leaching out the bad substances and getting rid of them effectively. 14 people found this helpful

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