Peripheral nervous system

The peripheral nervous system (PNS) is the part of the nervous system that consists of nerves and ganglia outside the central nervous system (CNS). The PNS consists of peripheral nerves and their associated ganglia - collections of nerve cell bodies.

The PNS can be divided in two parts based on their function: the autonomic (vegetative) nervous system and the somatic nervous system. The autonomic nervous system can be further divided into two functional components: the sympathetic nervous system and the parasympathetic nervous system.

Topographically, the peripheral nervous system consists of two parts, a spinal and a cranial part. The cranial part of the peripheral nervous system is represented by 12 pairs of cranial nerves, while the spinal part is formed by 31 pairs of spinal nerves.

References:

1. Crossman, A. R., & Neary, D. (2019). Neuroanatomy: an Illustrated Colour Text (6th ed.). Elsevier.
2. Vanderah, T. W., & Gould, D. J. (2020). Nolte’s The Human Brain (8th ed.). Elsevier.