Glial cell

Glial cells are support cells for the nervous system. In Greek, Glia means "glue". Glia are said to be the glue of the nervous system.^[1] Glia occur in both grey matter and white matter.

Neuroglia of the brain shown by Golgi's method

23 week foetal brain culture astrocyte (a type of glia)

Glia are thought to have four main functions:

1. To surround neurons and hold them in place,
2. To supply nutrients and oxygen to neurons,
3. To insulate one neuron from another,
4. To destroy pathogens and remove dead neurons.

Glia may have more functions than just these four.^[2]

Types of Macroglia

Location	Name	Description
CNS	Astrocytes	Astrocytes form the blood-brain barrier and guide axons.
CNS	Oligodendrocytes	Oligodendrocytes are cells that form a myelin sheath, which coats the axons of neurons (to make impulses travel faster) in the Central Nervous System. These are the opposite of Schwann Cells.
PNS	Schwann cells	Schwann Cells are very similar to oligodendrocytes in that they form the myelin sheath, but they do it for the neurons located in the Peripheral Nervous System. They also clear cellular debris to allow for the regrowth of neurons
CNS	Ependymal cells	Ependymal cells create and secrete cerebrospinal fluid, which surrounds the brain and spinal cord.
PNS	Satellite cells	Satellite cells are small cells that help regulate the external chemical environment.

Descriptions of Glial Cells

Role in degenerative brain diseases

A type of glial cell is thought to play a role in amyotrophic lateral sclerosis (ALS or motor neurone disease), Alzheimer's disease (a type of dementia) and Parkinson's disease.

The microglia are the macrophages of the nervous system. In these neurodegenerative disorders, it is thought that the microglia digest healthy brain cells, causing the degeneration of brain function. This is especially true for Parkinson's disease, where the Glia break down dopaminergic cells, causing the symptoms associated with Parkinson's.^[3][4]