Final answer:
Microglia are the glial cells in the CNS that act as scavengers, removing waste and protecting the brain from pathogens.
Step-by-step explanation:
The glial cells that act as scavengers in the central nervous system (CNS) are microglia. Microglia are responsible for phagocytosis, helping to eliminate waste and protect the brain from invading microorganisms. They play a critical role in immune surveillance and are related to macrophages found in other parts of the body.
Other glial cells in the CNS include astrocytes, which maintain the chemical environment and form the blood-brain barrier; oligodendrocytes, which produce the myelin sheath around CNS axons; and ependymal cells, which are involved in the production of cerebrospinal fluid. In contrast, in the peripheral nervous system (PNS), Schwann cells provide myelin for axons and satellite cells support neurons.