Which two glial cell types form the main CNS glial classes?

Which two glial cell types form the main CNS glial classes?

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

Answer: (C)

The main concept is identifying the two glial cell types that form the major glial populations in the central nervous system. In the CNS, the two principal glial classes are astrocytes and oligodendrocytes. Astrocytes are versatile support cells that help maintain the brain’s environment: they regulate extracellular ion balance, clear neurotransmitters, provide metabolic support to neurons, and contribute to the blood-brain barrier and tissue repair after injury. Oligodendrocytes are the myelinating cells of the CNS; each oligodendrocyte extends multiple processes that wrap around several axons to form myelin sheaths, which speed up nerve conduction. Other glial types exist in the CNS, such as microglia, which act as resident immune cells, and ependymal cells, which line the ventricles and participate in CSF dynamics. Schwann cells and satellite cells are glia of the peripheral nervous system, not the CNS. Neurons are not glial cells. Therefore, astrocytes and oligodendrocytes constitute the main CNS glial classes.

The main concept is identifying the two glial cell types that form the major glial populations in the central nervous system. In the CNS, the two principal glial classes are astrocytes and oligodendrocytes.

Astrocytes are versatile support cells that help maintain the brain’s environment: they regulate extracellular ion balance, clear neurotransmitters, provide metabolic support to neurons, and contribute to the blood-brain barrier and tissue repair after injury. Oligodendrocytes are the myelinating cells of the CNS; each oligodendrocyte extends multiple processes that wrap around several axons to form myelin sheaths, which speed up nerve conduction.

Other glial types exist in the CNS, such as microglia, which act as resident immune cells, and ependymal cells, which line the ventricles and participate in CSF dynamics. Schwann cells and satellite cells are glia of the peripheral nervous system, not the CNS. Neurons are not glial cells. Therefore, astrocytes and oligodendrocytes constitute the main CNS glial classes.