skip to main content

Area Postrema No BBB — FRCA Primary MCQ

Instant feedback + full explanation. One question, done properly.

HardPhysiology - NeurophysiologyArea Postrema No BBBFRCA Primary

Which structure is a circumventricular organ with a reduced blood–brain barrier, allowing detection of circulating emetogenic substances?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — The area postrema at the caudal floor of the fourth ventricle

The best answer is “The area postrema at the caudal floor of the fourth ventricle”. The area postrema is a circumventricular organ at the caudal fourth-ventricle floor. Its permeable capillaries permit monitoring of circulating toxins and drugs and contribute to the chemoreceptor trigger zone. The cortex, hippocampus, thalamus and cerebellar cortex are protected by the usual blood–brain barrier.

Reference: Royal College of Anaesthetists, Primary FRCA Syllabus 2021: https://www.rcoa.ac.uk/sites/default/files/documents/2026-01/Primary-FRCA-Syllabus.pdf