Which cells act as immune defense in CNS?

Which cells act as immune defense in CNS?

• A. Astrocytes
• B. Ependymal cells
• C. Microglia
• D. Oligodendrocytes

Answer: (C)

Microglia are the immune sentinels of the central nervous system. They are the resident immune cells in the brain and spinal cord, constantly surveying the neural environment. When there’s infection, injury, or debris, they activate, phagocytose invaders or damaged material, and release signaling molecules that tailor the inflammatory response. This macrophage-like role inside the CNS is unique among glial cells, which is why microglia are the primary immune defense in the CNS. Astrocytes mainly support neurons, help maintain the blood–brain barrier, regulate ion and neurotransmitter balance, and respond to injury in other ways. Ependymal cells line the ventricles and help produce and circulate cerebrospinal fluid. Oligodendrocytes create myelin sheaths to insulate axons. While all are essential for CNS function, they do not serve as the primary immune effector cells.

Microglia are the immune sentinels of the central nervous system. They are the resident immune cells in the brain and spinal cord, constantly surveying the neural environment. When there’s infection, injury, or debris, they activate, phagocytose invaders or damaged material, and release signaling molecules that tailor the inflammatory response. This macrophage-like role inside the CNS is unique among glial cells, which is why microglia are the primary immune defense in the CNS.

Astrocytes mainly support neurons, help maintain the blood–brain barrier, regulate ion and neurotransmitter balance, and respond to injury in other ways. Ependymal cells line the ventricles and help produce and circulate cerebrospinal fluid. Oligodendrocytes create myelin sheaths to insulate axons. While all are essential for CNS function, they do not serve as the primary immune effector cells.