 sensory receptors throughout the body and send them to the brain.
- It also carries information from the brain through efferent fibres to the muscles and glands.
- It coordinates reflexes without the involvement of the brain.
Thus the spinal cord has both communicative and integrative functions.
- Excepting the sensory and motor functions spinal cord controls some other important function also. These are called as reflex actions.
- The spinal cord does not take any assistance from the brain. Reflex actions are automatic, unlearned, involuntary and in born responses.
- Therefore these actions are suddenly in nature and have a purpose of protecting the individuals or his / her organs from sudden danger.
Read the following sentences and compare with endocrine glands.
Pheromones are chemical substances secreted by organisms. These act as chemical signals secreted by exocrine glands. Pheromones are used as signals by the members of same species. Honey bee secretes pheromones that attract other bees to the location of food.
|Pheromones||Secretions of Endocrine glands (or) Hormones|
|1. Pheromones are chemical substances secreted by organisms.||1. Hormones are chemical substances secreted by endocrine glands.|
|2. These act as chemical signals.||2. These are the chemical messengers.|
|3. Pheromones are used as signals by the members of same species.||3. Hormones change or control the metabolic activities in the organisms.|
|4. Honey bee secretes pheromones that attract other bees to the location of food.||4. Hormones help for growth, and stimulated organs’ function.|
Collect the information about cranial nerves, spinal nerves from internet or from your school library.
Spinal cord :
- Spinal cord is a long and cylindrical structure passing through the vertebral column.
- The vertebrae (back bones) of the vertebral column protect the spinal cord from injuries.
- From the sides of spinal cord, 31 pairs of nerves take their origin one from each side and supply branches to various parts of the body.
- Basic function of spinal cord is to act as a relay station – receiving information from various parts of the body parts below the head and send this information to the brain.
- Similarly, it receives information from brain and sends this information to other parts of the body.
- In addition to this, spinal cord also plays a major role in the RFELEX ACTIONS.
- The message received from the sensory nerve is passed into spinal cord. It is analyzed by the INTER NEURON present in the spinal cord and response is given. It is conveyed to the effector organ through motor nerve. The effector organ shows the response.
- Thus spinal cord saves us from dangerous stimuli through it’s REFLEX ACTIONS.
Draw a picture representing connection between dendrite – dendrite, axon – dendrite. Why do they connect like that?
- The nerve cell is the structural and functional unit of nervous system.
- It consists of more than 100 billion of them, which communicate with each other in a specific manner.
- Dendrites of one nerve cell connects to the other or to the axons of another nerve cell through connect points called as a synapse.
Draw a neatly labelled diagram of Brain and write few points how it is protected.
Protection of Brain :
- Brain is present in the hard bony box called CRANIUM.
- It is covered by three layers called MENINGES.
- The space between the inner layer is filled with fluid called cerebrospinal fluid,
- It serves a shock-absorbing medium and protects brain against shocks/ jerks along with the meninges and cranium.
You are walking in the traffic suddenly you heard a loud sound. How does coordination take place in this situation among respected organs? Draw a block diagram to explain this situation.
Make a model of neuron using suitable materials.
Required materials: A chart, twine thread, fevicol, sticker.
Observe different actions performed by your classmate for a period of 45 minutes. Out of these actions which are controlled by voluntary and involuntary pathways?
- carrying books
- Blinking of eyes
- listening etc.
Its very interesting to 