circumventricular organs
Specialized brain regions lacking a typical blood-brain barrier, serving as interfaces between the CNS and systemic circulation.
Full Definition
Circumventricular organs are specialized regions of the central nervous system characterized by fenestrated capillaries and lack of a typical blood-brain barrier, allowing direct communication between the brain and systemic circulation. These structures include the area postrema, subfornical organ, organum vasculosum of the lamina terminalis, median eminence, neurohypophysis, pineal gland, and subcommissural organ. Circumventricular organs play crucial roles in neuroendocrine function, autonomic regulation, and immune surveillance. Their unique vascular properties make them important sites for pathogen entry, immune cell trafficking, and potential targets for neuroinflammatory processes.
Usage
Usage note: Always plural when referring to the collective structures; can be abbreviated as CVOs in technical contexts.
In Context
- "The circumventricular organs serve as important entry points for immune surveillance of the CNS." — Neuroanatomy textbook
- "Inflammatory mediators can access the brain through circumventricular organs that lack blood-brain barrier protection." — Neuroimmunology research