Organization of the Nervous System

Although terminology seems to indicate otherwise, there is really only one nervous system in the body. Although each subdivision of the system is also called a “nervous system,” all of these smaller systems belong to the single, highly integrated nervous system. Each subdivision has structural and functional characteristics that distinguish it from the others. The nervous system as a whole is divided into two subdivisions: the central nervous system (CNS) and the peripheral nervous system (PNS).