Circumventricular Organs

**Definition:** Highly vascularized and specialized tissues distributed principally along the midline of the VENTRICULAR SYSTEM from the FOREBRAIN to the HINDBRAIN. They are distinguished by their lack of normal BLOOD-BRAIN BARRIER and fenestrated capillaries and contain either neurosecretory neurons or chemoreceptors.

**Tree numbers:** - A06.688.178 - A08.713.049