Believed to play a role in memory storage. Nerve cell bodies in the PNS are arranged into functional clusters called ganglia . A nucleus is a similar functional cluster within the brain. Ganglia and nuclei allow coordination of activities by only part of the nervous system. The peripheral nervous system of humans consists of 12 pairs of cranial nerves and 31 pairs of spinal nerves.
Spinal nerves innervate the entire body and contain both sensory and motor neurons.
Maintain homeostasis by coordinating internal organ functions.