What are the two classes of glia in the CNS?

What are the two classes of glia in the CNS?

• A. Microglia and Schwann cells
• B. Ependymal cells and satellite cells
• C. Astrocytes and oligodendrocytes
• D. Neurons and astrocytes

Answer: (C)

Glial cells provide essential support to neurons. In the central nervous system, the two main glial types are astrocytes and oligodendrocytes. Astrocytes help maintain the brain’s chemical environment, support the blood-brain barrier, regulate ion balance, and provide metabolic support to neurons. Oligodendrocytes create myelin sheaths around axons within the CNS, with one oligodendrocyte wrapping multiple nearby axons to insulate and speed electrical conduction. This distinguishes them from glial cells in the peripheral nervous system, such as Schwann cells, which myelinate PNS fibers, and from other CNS glial types like microglia (immune cells) and ependymal cells (lining brain ventricles).

Glial cells provide essential support to neurons. In the central nervous system, the two main glial types are astrocytes and oligodendrocytes. Astrocytes help maintain the brain’s chemical environment, support the blood-brain barrier, regulate ion balance, and provide metabolic support to neurons. Oligodendrocytes create myelin sheaths around axons within the CNS, with one oligodendrocyte wrapping multiple nearby axons to insulate and speed electrical conduction. This distinguishes them from glial cells in the peripheral nervous system, such as Schwann cells, which myelinate PNS fibers, and from other CNS glial types like microglia (immune cells) and ependymal cells (lining brain ventricles).