The peripheral nervous system (PNS) consists of nerves that branch out from the CNS and connect it to other body parts. The PNS includes the cranial nerves, which emerge from the brain, and the spinal nerves, which emerge from the spinal cord.
The PNS can also be subdivided into the somatic and autonomic nervous systems. Generally, the somatic nervous system consists of the cranial and spinal nerve fibers that connect the CNS to the skin and skeletal muscles; it oversees conscious activities. The autonomic nervous system includes fibers that connect the CNS to viscera, such as the heart, stomach, intestines, and glands; it controls unconscious activities.