This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous system, Subject name: Physiology
Phagocytic cells in the CNS are 
Select and explain. 
A. Oligodendrocytes, B. Schwanncells, C. Astrocytes, D. Microglial cells
D: Microglial cells
Answer: D: Microglial cells 
Explanation: Microglia are scavenger cells that resemble tissue macrophages and remove debris resulting from injury infection and disease. Microglia arise from macrophages outside the nervous system. (Ref: Ganong&;s review of medical physiology; 23rd edition; pg:80)