Neuroglia

The supportive cells of the nervous system (glial cells) are approximately 10 times more abundant than neurons. Glial cells support neurons by providing nutrients, protection, removing debris and unwanted microorganisms, insulating electrical impulses, and coordinating neurons' activity.

Glial cells of the central nervous system include:

• Oligodendrocytes are large cells that form myelin sheaths.

• Ependymal cells line the fluid-filled cavities of the CNS.

• Microglia are phagocytic cells that traverse the CNS to remove debris and fight off intruding microorganisms.

• Astrocytes are the most abundant type of glial cells. They support the nervous tissue, and their extended pedicles (perivascular feet) wrap around capillaries to form the blood-brain barrier.

Glial cells of the peripheral nervous system include:

• Schwann cells wrap around and myelinate the neurons found in peripheral nerves. The Schwann cells also play a crucial role in the healing and regeneration of damaged neurons.

• Satellite cells surround the cell bodies of peripheral neurons, providing insulation and a stable chemical environment.