to bring about control and coordination.
- Another example for nervous and hormonal coordination. When the mother feeds the baby, the baby sucks the nipple for milk. This information is send to the brain by sensory nerve. Brain orders the pituitary gland to release the hormone oxytocin. Oxytocin helps in the ejection of milk from the mammary glands.
Consider that you are passing by a garbage disposal area and you immediately
cover your nose. Arrange the events below in a logical order by marking them from 1 to 5 to trace the events that happen in the nervous system from detection of foul smell (stimulus generation) to covering your nose (response).
i) At the end of the axon, electrical impulse releases chemicals.
ii) Stimulus received by the dendrites of a neuron sets off chemical reaction that creates an electrical impulse.
iii) Electrical impulse transmitted through cell body and axon.
iv) The chemicals cross the synapse and reach the next neuron. Similarly, the electrical impulse crosses several neurons.
v) Finally, the impulse is delivered from neuron to the gland that helps in recognition of the foul smell and muscle cells that help in covering the nose.
The following events occur in nervous system for detecting foul smell of garbage, ii, iii, i, iv, v
What is a Synapse? How is it useful in transfer information?
- Definition: Synapse is a functional region between two neurons where information from one neuron is transmitted or relayed to another neuron.
- Through synaptic region is with minute gaps it does not have any protoplasmic connection between them.
- Information is passed from one nerve cell to the other through these gaps either in the form of chemical or electrical signals or both.
a) Stimulus and Response
b) Afferent and Efferent nerves
c) Central nervous system and peripheral nervous system
d) Receptor and effector
a) Stimulus and Response
|1. It is the cause or change in organism’s surroundings that causes the organism to react||1. It is the act done by the organism.|
|2. Stimulus can not be always controlled especially external stimuli.||2. It could be controlled.|
|3. Stimulus could be of any magnitude.||3. The response could never go beyond the highest capability of an organism.|
|4. Response can not determines the stimulus.||4. Stimulus determines the response.|
b) Afferent and Efferent nerves
|Afferent nerves||Efferent nerves|
|1. Nerves coming from receptors or sense organs are called afferent nerves.||1. Nerves that carry impulses from brain or spinal cord are called efferent nerves.|
|2. These are also called sensory nerves.||2. These are also called motor nerves.|
|3. Sensory nerves carry information from sensory organs like ears, eyes, from brain or spinal cord.||3. The motor nerves carry impulses to effector nose, tongue and skin to brain and organs (muscles) and are responsible for the movement of hands and legs.|
|4. These are incoming nerves.||4. These are outgoing nerves.|
c) Central nervous system and peripheral nervous system :
|Central nervous system||Peripheral nervous system|
|1. It consists of Brain and spinal cord.||1. It consists of nerves that arise from brain and spinal nerves.|
|2. Both of them have nerve cells and glial cells.||2. It has 43 pairs of nerves. Among them 12 pairs are cranial nerves and 31 pairs are spinal nerves.|
|3. Brain and spinal cord are continuous with each other.||3. Cranial nerves take their origin from brain and spinal nerves take their origin from spinal cord.|
|4. Brain and spinal cord receive information.||4. The cranial nerves carry information to the sense organs and spinal nerves from organs to spinal cord.|
|5. Central nervous system coordinates all neural functions.||5. These supply information required for the movement of the muscles.|
d) Receptor and effector:
|1. The sense organs which are made up of cells called receptors.||1. Muscles or tissues which are linked with nerves are called an effector.|
|2. Receptors respond to stimulus.||2. Effectors are the organs that produce response.|
|3. These send information to central nervous system.||3.