Monday, April 27, 2009

Glial Cells

Glial cells, or neuroglia, are non-neuronal, supporting cells which surround neurons and their axons to provide support, nutrition, and electrical insulation between neurons. They form myelin, and participate in signal transmission in the nervous system. In the human brain, there is about one glia cell for every neuron with a ratio of about two neurons for every three glia cells in the cerebral gray matter.

The neuroglia cells are thus known as the "glue" of the nervous system. The five main functions of glial cells are to surround neurons and hold them in place, to supply nutrients and oxygen to neurons, to insulate one neuron from another, and to destroy pathogens and remove dead neurons, to modulate neurotransmission. There are four types of glia cells: Astrocytes, Oligodendrocytes, and Microglia in the Central Nervous System; Schwann cells in Peripheral Nervous System.