Several types of glial cells support neurons in the nervous system. The axons of
In the central nervous system (the brain and spinal cord), oligodendrocytes use their processes to wrap many layers of myelin around each axon. Each oligodendrocyte insulates many axons.
In the peripheral nervous system (outside of the brain and spinal cord), a single axon is coated by many Schwann cells that wrap themselves around a portion of a single axon to cover it with myelin.
Astrocytes are another type of glial cell that function to support neurons in the central nervous system. Astrocytes provide metabolic support to neurons and maintain the extracellular environment so that neuronal signaling can occur. Some astrocytes have processes that coat the outside of blood vessels in the brain and help to form a tight blood-brain barrier that protects the brain from toxic substances in the blood.
Microglial cells are scavenger cells of the nervous system that can take up cellular debris as well as serve other immune functions for the brain.
Ependyma cells cover the internal cavities of the central nervous system.
Neurons are the cells of the nervous system that communicate and integrate