Overview

The peripheral nervous system (PNS) includes all the rest of the nervous system aside
from the central nervous system. This means that it comprises the 12 pairs of cranial
nerves that originate directly from the brain and spread to different parts of the body
bypassing the spinal cord, and the 31 pairs of spinal nerves that pass through the spinal
cord and spread to different parts of the body. Thus, the PNS is mainly constituted of
nerve. PNS is sometimes further classified into voluntary nervous system and the
autonomic nervous system. This is based on the fact that the nerves in the former system
are involved in making conscious movements, whereas those in the latter system make
movements over which the person does not have control. Obviously, the former category
of nerves includes those associated with the muscles of touch, smell, vision, and skeleton.
The latter includes nerves spread over muscles attached with heart beats, blood pressure,
glands, and smooth muscles.