The somatic nervous system (SoNS Or voluntary nervous system) is the part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles. The SoNS consists of efferent nerves responsible for stimulating muscle contraction, including all the non-sensory neurons connected with skeletal muscles and skin.
There are 43 segments of nerves in our body and with each segment, there is a pair of sensory and motor nerves. In the body, 31 segments of nerves are in the spinal cord and 12 are in the brain stem.
Besides these, thousands of association nerves are also present in the body.
Thus Somatic Nervous System consists of three parts:
i) Spinal Nerves: They are peripheral nerves that carry sensory information into the spinal cord and motor commands.
ii) Cranial Nerves: They are the nerve fibers that carry information into and out of the brain stem. They include smell, vision, eye, eye muscles, mouth, taste, ear, neck, shoulders, and tongue.
iii) Association Nerves: These nerves integrate sensory input and motor output numbering thousands.