Which structures are excluded from the peripheral nervous system?

The brain and spinal cord are excluded from the peripheral nervous system because they are part of the central nervous system (CNS). The central nervous system is responsible for processing and integrating information and serves as the control center of the body. It consists of the brain, which processes sensory data, coordinates responses, and facilitates cognitive functions, and the spinal cord, which serves as a communication pathway between the brain and the rest of the body.

In contrast, the peripheral nervous system (PNS) includes all the nerves that branch out from the central nervous system, including cranial nerves that extend from the brain and spinal nerves that extend from the spinal cord to various parts of the body. The PNS has the essential role of connecting the CNS to limbs and organs, thus facilitating sensory and motor functions. Understanding this distinction is crucial for comprehending the overall organization of the nervous system.