THE PERIPHERAL NERVOUS SYSTEM

The Peripheral Nervous System (PNS) is the attachment to the CNS which connects sensory organs and to the rest of the body. It's nerves extend outward from the spinal cord, much like branches from a tree's trunk and create a network of neurons which enable humans to feel, analyze the feeling, and respond to it, within the span of a second. Here is a diagram of both the CNS and the attached PNS.

If the CNS was the main power line, the PNS is made of all the smaller power lines extending from the main line.This system is divided into two categories, the Sensory-Somatic System and the Autonomic System.


The Sensory-Somatic System is composed of 12 different cranial nerves which extend from the cranium, or skull, and of 31 spinal nerves which extend from the spine. It controls the body's voluntary responses such as response to touch, hearing, and sight.


The Autonomic System controls the involuntary actions such as breathing, heart contractions, digestion, and exocrine and endocrine gland productions. It is also responsible for "fight or flight" responses  and even the dilation of pupils according to different amounts of light. Both the CNS and the PNS work together to allow the human body to function smoothly and efficiently.

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