Location
The paraventricular nucleus lies adjacent to the third ventricle, from which it derives its name, "paraventricular" meaning "alongside a ventricle."
It does lie within the periventricular zone and must not be confused with the periventricular nucleus, which occupies a more medial position, beneath the third ventricle.
The PVN is highly vascularised and is protected by the blood–brain barrier, although its neuroendocrine neurons extend to sites (in the median eminence and in the posterior pituitary) beyond the blood–brain barrier.
Read more about this topic: Paraventricular Nucleus Of Hypothalamus