Central Nervous System

1222 WordsJul 7, 20095 Pages
The central nervous system (CNS) is that portion of the vertebrae nervous system that is composed of the brain and spinal cord. Together with the peripheral nervous system (PNS), the other major portion of the nervous system, the CNS coordinates the body's interaction with the environment. The CNS is contained within the dorsal cavity, with the brain in the cranial subcavity (the skull), and the spinal cord in the spinal cavity (within the vertebral column). Then human nervous system is the most complex object know to science, as it includes the intricate CNS and a brain with 10 billion neurons and many times more interneural connections (Anissimov 2007). For some people, this brain and the increase in intelligence it signifies is what…show more content…
Glial cells, also called neuroglia or simply glia, are non-neuronal cells that provide support and nutrition, maintain homeostasis, form myelin, and participate in signal transmission in the nervous system. In the human brain, glia are estimated to outnumber neurons by about 10 to 1 (SFN 2000). The axon of a neuron (nerve cell) is a long, slender projection that conducts electrical impulses away from the neuron's cell body, or soma. The axons of neurons may or may not be coated with myelin. Myelin is a phospholipid layer that is an outgrowth of glial cells. Myelin-coated axons appear white, and thus these regions of the CNS are called "white matter," while "gray matter" is composed of unmyelinated neurons. Cerebral and spinal white matter do not contain dendrites, which can only be found in gray matter. Dendrites are branched projections of a neuron that act to conduct the electrical stimulation received from other neural cells to the cell body. Gray matter contains dendrites, along with neural cell bodies and shorter axons. Generally, white matter can be understood as the parts of the brain and spinal cord responsible for information transmission (axons); whereas, gray matter is mainly responsible for information processing (neuron bodies). In the human spinal cord, the axons coated with myelin are on the surface and the axon-dendrite networks are on the inside, while in the brain this is reversed (Chamberlin and Narins 2005). n the developing

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