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
[{'content': 'Phagocytic cells in the CNS are \nSelect and explain. \nA. Oligodendrocytes, B. Schwanncells, C. Astrocytes, D. Microglial cells', 'role': 'user'}, {'content': 'Answer: D \nExplanation: 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)', 'role': 'assistant'}]