GENERAL HISTOLOGY

Detailed explanation-1: -Microglia, the innate immune cells in the CNS, have two primary roles in the brain that are common to myelomonocytic innate immune cells in all mammalian organs: they fight off and phagocytize viruses, bacteria, and other foreign invaders, and they remove cellular debris to facilitate wound repair.

Detailed explanation-2: -While microglial cells in mammals are the principal phagocytes in the CNS, Schwann cells of the peripheral nervous system (PNS) can assist blood-derived macrophages in removing myelin debris and have been recognized as playing a key role in synapse removal during development of the PNS (Bishop et al., 2004).

Detailed explanation-3: -Several types of cells of the immune system perform phagocytosis, such as neutrophils, macrophages, dendritic cells, and B lymphocytes. The act of phagocytizing pathogenic or foreign particles allows cells of the immune system to know what they are fighting against.