Basic properties of microglia Options

[Graeber]

Microglia represent the intrinsic macrophages of the nervous system. They are resident cells and ubiquitously distributed in non-overlapping territories throughout the CNS. They comprise 10-20% of the total glial cell population. The role of microglia in various pathological conditions was first fully recognized by del Rio-Hortega who also coined the term. The nature and identity of microglial cells have long been debated but it is now generally accepted that they are developmentally related to cells of the mononuclear phagocyte lineage. This makes them different from all other parenchymal cell types in the CNS. Functionally, microglia form a network of immune competent cells throughout the brain and spinal cord and they respond even to the slightest alterations in their microenvironment, i.e. they function as a ‘sensor to threats' to the CNS (G.W. Kreutzberg). This is of practical diagnostic utility.