What are the different types of glial cells?

Glial cells play a supportive role in the nervous system. The four types of glial cells in the central nervous system (CNS) and two types in the peripheral nervous system (PNS). 

Glial cells in the CNS 

1. Astrocytes are star-shaped cells found only in the brain and spinal cord. 
2. Oligodendrocytes create myelin, a fatty material that wraps around axons of the nerve cells, insulating them and enabling electrical signals to travel faster along axons. 
3. Microglia are small, star-shaped cells that act as immune cells protecting the brain and spinal cord against invading organisms or disease-causing agents.
4. Ependymal cells develop in the ventricles of the brain and the central canal of the spinal cord.
5. Radial glia are capable of generating new cells and serve as precursors to neurons, oligodendrocytes, and astrocytes. They are considered as a type of stem cell in the brain. 

Glial cells in the PNS 

The peripheral nervous system (PNS) encompasses the nerves outside the brain and spinal cord. Glial cells in the PNS play a vital role in carrying signals to and from the CNS. There are two main types of glial cells in the peripheral nervous system - Schwann cells and satellite cells.

1. Schwann cells are a type of satellite cell that function in a manner similar to oligodendrocytes in the CNS. 
2. Satellite cells help maintain the environment around neurons by providing the peripheral nerves with nutrition and support and regulating their calcium levels, which are crucial for proper nerve conduction.