The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord, while the PNS includes all the nerves outside the CNS. The PNS is further divided into the somatic nervous system, which controls voluntary movements, and the autonomic nervous system, which regulates involuntary functions. The autonomic nervous system is subdivided into the sympathetic and parasympathetic systems.
