The paraventricular nucleus (PVN) is a nucleus in the hypothalamus that lies right beside the third ventricle, one on each side. Its large neurons make oxytocin and vasopressin, which the posterior pituitary releases into the blood. [1][2]
The 3D brain needs JavaScript. The text below still says where the paraventricular nucleus is and what it does.
Opens cut by a side (sagittal) slice through the hypothalamus, which holds the paraventricular nucleus. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
Not a separate shape in this atlas; lit: the part that holds it. Lit: the whole hypothalamus. The paraventricular nucleus is a small nucleus inside the hypothalamus, against the wall of the third ventricle; it has no shape of its own in the BodyParts3D model, so the whole hypothalamus is lit and nothing is drawn at a guessed point. [1][3]
Lit here: the hypothalamus, the part that holds the paraventricular nucleus — see it on its own page.
It lies next to the third ventricle, in the periventricular zone of the hypothalamus; it is not the periventricular nucleus, which lies further in, beneath the ventricle. [1]
It is small: in the rat it holds about 100,000 neurons in about 0.5 cubic millimetre. It is richly supplied with blood vessels and sits behind the blood–brain barrier, though its hormone-releasing endings reach beyond it. [1]
What it does
Its large (magnocellular) neurons make oxytocin and vasopressin; the hormones travel down their axons through the pituitary stalk and are released into the blood from the posterior pituitary. That hormone route is the hormones page’s posterior-pituitary step. [1][2]
Its small (parvocellular) neurons send corticotropin-releasing hormone (CRH), thyrotropin-releasing hormone (TRH) and other signals to the median eminence, from where portal veins carry them to the anterior pituitary, which answers with ACTH and TSH. [1]
Other cells project to the brainstem and spinal cord, so it also takes part in the autonomic nervous system; it is linked with water balance, appetite, wakefulness, stress responses and social behaviour. [1]
Connections
Its axons run to the posterior pituitary, the median eminence, the brainstem and the spinal cord. The supraoptic nucleus, lower down above the optic chiasm, has the same kind of oxytocin- and vasopressin-making neurons. [1][4]
Other names
“Paraventricular” means beside the ventricle. Textbooks often simplify the pair to “the paraventricular nuclei make oxytocin, the supraoptic nuclei make ADH” (vasopressin); in fact both nuclei hold neurons making each hormone. [2][1][4]
Size
The model has no shape for the paraventricular nucleus itself, so it is not measured here. The hypothalamus that holds it measures about 18 mm front to back, 20 mm top to bottom and 17 mm side to side on this model (the box it fits in, not its volume). [5]
Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain.