The Central Nervous System ( Cns ) Essay

1238 Words Jun 5th, 2016 null Page
Neurons are not the only cells that occupied the central nervous system (CNS). In fact, neurons are outnumbered by supportive non-excitable cells, collectively called neuroglia (a.k.a. glia). The term glia was coined by Rudolph Virchow in 1859 to indicate the “connective tissue” surrounding the neurons (glia came from Greek meaning glue). However, the combination of the activities of glial cells and neurons is crucial for brain functions (Steward 2000).
There are three types of glial cells in the CNS that can be distinguished by size and embryonic origin: oligodendrocytes (a.k.a. oligodendroglia), astrocytes (a.k.a. astroglia) and microglia (Fig. 1.1). In the peripheral nervous system (PNS) Schwann cells can be found. Astrocytes and oligodendrocytes originate from the neuroepithelium, whereas microglia originate from the mesoderm. Oligodendrocytes and Schwann cells are in control of myelin production and are thus responsible for the high speed processing of signals through the axons. Astrocytes are a heterogeneous cell population that interact with neurons and blood vessels to detect neuronal activities and maintain neuronal networks. Microglial cells are the immune cells of the CNS that response to all changes in the nervous system. Therefore, they are also called the pathological sensors of the brain. Microglial cells have the ability to migrate to the site of damage and proliferate to become phagocytes that interact with the peripheral immune system by antigen presenting…

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