central line

central nervous system That part of the nervous system that consists of the brain and spinal cord. Abbreviated CNS. The CNS is one of the two major divisions of the nervous system. The other is the peripheral nervous system (PNS), which is outside the brain and spinal cord. The PNS connects the CNS to sensory organs, such as the eye and ear, and to other organs of the body, muscles, blood vessels, and glands.