V. Microglia
A. Characteristics of normal microglia
Microglia are mesoderm-derived cells (in contrast to the macroglia -- astrocytes, oligodendrocytes, and ependyma -- which are derived from neuroectoderm). Microglia are the CNS representatives of the reticuloendothelial system. One major function is to serve as a fixed macrophage system.
B. Pathological reactions
Microglial cells become activated in response to injury and may respond by
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proliferation
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developing elongated nuclei (rod cells)
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forming aggregates around areas of tissue necrosis or dying neurons (neuronophagia, microglial nodule or shrub
In addition to microglia, blood-derived macrophages serve as phagocytic cells in the CNS. |