Question

List and describe all of the different types of glial cells found in the central nervous system. Be sure to include the functions of each.

Answer 1

What are glial cells ?

The non neuronal cells that surround the neuron and are found in central nervous system and peripheral nervous system. They're non neuronal because they donot produce electrical impulses like neurons.

Types of Glial Cells -

1. oligodendrocytes
2. astrocytes
3. ependymal cells
4. microglia

Oligodendrocytes -

1. They are large glial cells
2. They create myelin sheath of axons.
3. Because of myelin sheath, they are responsible to support and insulate the axons.
4. They are found only in brain and spinal cord i.e. central nervous system

Astrocytes -

1. These are star shaped glial cells that are found in abundant in CNS.
2. They are responsible for homeostasis and provide nutrients to the neurons.
3. They regulate electrical impulses in the brain.
4. They have gylcogen and so perform glyconeogenesis.
5. They regulate the blood brain barrier which is semipermeable lining of epithelial cells.

Ependyma -

1. These glial cells makes the epithelial lining of brain and spinal cord. (particularly ventricles in brain and central canal in spinal cord)
2. They are attach to the astrocytes via tentacle like extensions.
3. They produce and regulate the cerebrospinal fluid. This is because they modify themselves and join together to form the choroid plexus.

Microglia -

1. They are type of macrophages glial cells found in CNS.
2. As they are macrophages,they are responsible for immunity of CNS.
3. Whenever there is an injury these cells assemble together at the damaged site and remove the damaged cells by engulfing them.
4. They also maintain homeostasis.