The peripheral nervous system consists of nerves that branch out from the brain and spinal cord. It is divided into the somatic nervous system and the autonomic nervous system. The somatic nervous system controls voluntary body movements through connections to skeletal muscles. The autonomic nervous system regulates involuntary functions like heart rate and digestion through its sympathetic, parasympathetic, and enteric divisions. Ganglia function as relay stations along peripheral nerves, containing neuron cell bodies outside the central nervous system.