microglia
Immune cells of the central nervous system that monitor brain health and respond to injury or infection.
Full Definition
Microglia are specialized immune cells that comprise approximately 10-15% of all cells in the central nervous system. These cells originate from myeloid precursors in the yolk sac during early embryogenesis and migrate to the brain where they establish permanent residence. In their resting state, microglia continuously survey the brain parenchyma with highly motile processes, monitoring for signs of damage, infection, or abnormal protein accumulation. Upon activation, they can phagocytose cellular debris, release inflammatory mediators, and present antigens. Microglial dysfunction is implicated in numerous neurological conditions including Alzheimer's disease, Parkinson's disease, and multiple sclerosis.
Usage
Usage note: Distinguished from peripheral macrophages by their CNS-specific origin and functions.
In Context
- "Activated microglia were observed surrounding amyloid plaques in the Alzheimer's disease brain tissue." — Neuropathology report
- "The anti-inflammatory drug specifically targeted microglial activation to reduce neuroinflammation." — Pharmacology study