Central nervous system

Article By:

Webster, Douglas B. Department of Otorhinolaryngology and Biocommunication, Louisiana State University Medical Center, Baton Rouge, Louisiana.

Last reviewed:April 2022

DOI:https://doi.org/10.1036/1097-8542.119300

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• Central nervous system, published June 2014:Download PDF Get Adobe Acrobat Reader

The portion of the nervous system composed of the brain and spinal cord in vertebrates. The division of the vertebrate nervous system comprising the brain and spinal cord is known as the central nervous system (see illustration). In general, the central nervous system is responsible for the processing of information that is received from various parts of the vertebrate body; it receives information from sensory neurons and responds via motor neurons (the sensory and motor neurons are components of the peripheral nervous system). The brain is enclosed in the skull, and the spinal cord is enclosed within the spinal canal of the vertebral column. The brain and spinal cord are intimately covered by membranes called meninges, and are protectively bathed in a clear, colorless extracellular fluid called cerebrospinal fluid. Approximately 90% of the cells of the central nervous system are glial cells. These cells support (both physically and metabolically) the other 10% of the cells, which are the nerve cells or neurons. Although the glial cells are much more numerous than neurons, the glial cells are also much smaller and do not directly participate in the propagation and integration of information. See also: Brain; Meninges; Nerve; Nervous system (vertebrate); Neuron; Spinal cord

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