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.

Synonyms: Circumventricular Organ, Secretory, Sensory Circumventricular Organ, Organs, Secretory Circumventricular, Organ, Neurohemal, Sensory Circumventricular Organs, Organ, Sensory Circumventricular, Circumventricular Organs, Secretory, Neurohemal Organs, Organ, Secretory Circumventricular, Neurohemal Organ, Circumventricular Organs, Sensory, Organs, Neurohemal, Circumventricular Organ, Sensory, Secretory Circumventricular Organ, Organ, Circumventricular, Circumventricular Organs, Secretory Circumventricular Organs, Circumventricular Organ, Organs, Sensory Circumventricular, Organs, Circumventricular