Glial cells provides physical support to the neurons and provide important biochemical support.
The peripheral nervous system (PNS) has two types of Glial cells;
- a. Schwann cells - support and insulate axons by forming myelin. In addition to providing support, the myelin acts as insulation around axons and speeds up their signal transmission.
- b. Satellite Cell - is a nonmylinating Schwann cell. Satellite cell form supportive capsule around nerve cell bodies located in the ganglia.
The Central Nervous System (CNS) has four types;
a. Oligodendrocytes - is a myelin forming glial in the CNS, it support and insulate several axon by forming myelin.
b. Astrocytes- has multiple roles , synapses, where they take up and release chemicals, provides neurons with substrates for ATP production, maintain homeostasis in the CNS extracellular fluid by taking K+ and water, act as blood-brain barrier that regulate the movement of materials between blood and extracellular fluid.
c. Microglia - are specialized immune cells that reside permanently in the CNS. When activated they remove damaged cell and foreign invaders.
d. Ependymal Cells- that create a selectively permeable epithelial layer that separates the fluid compartments of the CNS. The ependyma is one source of neural stem cell, immature cells that can differentiate into neurons and glial cells.