Glial cells

This man's head is on fire, due to failure of the glial cells to maintain a health neuronal operating environment.

What are they?

Glial cells make up 90% of the nervous system, creating and maintaining an environment for the neurones to function.

What types are there?

There are many types, the key ones being:

• Astrocytes - starfish-shaped cells which have long processes which wrap around capillaries in the brain to form the blood brain barrier
• Oligodendrocytes - the myelinating cells in the CNS which wrap around 3-50 adjacent axons, insulating them from each other and allowing higher speeds of action potential conduction
• Ependymal cells - form the lining of the ventricles. In the lateral ventricles they form the choroid plexus which produces CSF.
• Microglia - the macrophages of the brain
• Schwann cells - the myelinating cells in the PNS which wrap around one axons, insulating it and allowing higher speeds of action potential conduction