4main divisions of the peripheral nervous system and explain each function

The four main divisions of the peripheral nervous system are the somatic nervous system, the autonomic nervous system, sympathetic division, and parasympathetic division.

Explanation:

The somatic nervous system is what controls our voluntary bodily functions such as picking up a pencil or walking. The autonomic nervous system is what controls the involuntary bodily functions like digestion, heartbeat, and breathing. The autonomic nervous system is broken down into another two divisions, which are sympathetic and parasympathetic. The sympathetic division rouses the body and triggers the "fight or flight" response. It expands our pupils, and, basically, it makes us more alert. The parasympathetic division (known as "rest and digest") contracts the pupils and calms the body down, conserving energy. The two divisions work together to keep a stable internal environment.