CIRCLE OF WILLIS-CIRCUMVENTRICULAR ORGANS

SUMMARY

1. Areas of the brain that possess fenestrated capillaries, hence lying outside the blood brain barrier (BBB)

FUNCTIONS
2. Neurohemal organs: contain neurons secreting polypeptides directly into the circulation
3. Chemoreceptor zones to sample circulating blood

ORGANS
4. Posterior pituitary & adjacent ventral part of the median eminence of the hypothalamus
5. Area postrema: vomit center, cardiovascular center
6. Organum vasculosum of the lamina terminalis (OLVT): osmoreceptor controlling vasopressing secretion
7. Subfornical organ (SFO): AT-II acts here to increase water intake

Reference(s)

R.M.H McMinn (1998). Last’s anatomy: regional and applied. Edinburgh: Churchill Livingstone. Get it on Amazon.
Drake, Richard L., et al. Gray's Anatomy for Students. Elsevier, 2023. Get it on Amazon.