Microglia The above picture presents a clear view of a microglial cell.
Microglia are the smallest of the glial cells.
Some act as phagocytes cleaning up CNS debris. Most serve as representatives of the immune system in the brain. Microglia protect the brain from invading microorganisms and are thought to be similar in nature to microphages in the blood system. The dark brown figures in the above picture are microglial cells.