system - a group of physiologically or anatomically related organs or parts; "the body has a system of organs for digestion"

nervous system, systema nervosum - the sensory and control apparatus consisting of a network of nerve cells

glia, neuroglia - sustentacular tissue that surrounds and supports neurons in the central nervous system; glial and neural cells together compose the tissue of the central nervous system

brain, encephalon - that part of the central nervous system that includes all the higher nervous centers; enclosed within the skull; continuous with the spinal cord

substantia alba, white matter - whitish nervous tissue of the CNS consisting of neurons and their myelin sheaths

corticospinal tract, pyramidal motor system, pyramidal tract - any of the important motor nerves on each side of the central nervous system that run from the sensorimotor areas of the cortex through the brainstem to motor neurons of the cranial nerve nuclei and the ventral horn of the spinal cord

medulla spinalis, spinal cord - a major part of the central nervous system which conducts sensory and motor nerve impulses to and from the brain; a long tube-like structure extending from the base of the brain through the vertebral canal to the upper lumbar region