Final answer:
The phagocytic cells in the CNS that scavenge for pathogens and dead cells are the microglia.
Step-by-step explanation:
The phagocytic cells in the central nervous system (CNS) are the microglia. Microglia act as the main form of active immune defense in the CNS. These cells are responsible for scavenging the CNS for plaques, damaged neurons, and infectious agents. Astrocytes maintain the chemical environment and the blood-brain barrier, oligodendrocytes form myelin around CNS axons, and ependymal cells produce cerebrospinal fluid. Microglia, however, are uniquely equipped to act as macrophage-like cells, engulfing and destroying pathogens and debris.