(a) Name the structural and functional unit of nervous system.(b) Draw a flow chart to show the classification of nervous system into various parts.(c) What is autonomic nervous system? What is its function?(d) What is voluntary nervous system? Explain the working of voluntary nervous system with an example.

(c) The autonomic nervous system means self-governing nervous system. It regulates the functions of the internal organs of the body. The vital function is to controls and regulates the involuntary actions of the body like breathing, heartbeat, blood flow, and digestion.

(d) The voluntary nervous system is the part of the nervous system which helps us to take voluntary actions which are under the conscious control of the brain. It is responsible for carrying motor and sensory information both to and from the central nervous system (CNS).  It is also responsible for sensing external stimuli, which helps the body to remain in touch with its surroundings.

For example, when the skin is penetrated by a pointed object like a thorn, the pain is detected by the pain receptor. The nerve impulses are generated in the sensory nerves and conducted to the brain. The brain sends instructions to the skeletal muscles (effector muscle) through the motor nerves to remove the thorn. Then the muscle acts accordingly and removes the thorn.