The supraoptic nucleus (SON) is a nucleus of large hormone-making neurons at the base of the hypothalamus, next to the optic chiasm; one on each side. It makes vasopressin (antidiuretic hormone, ADH) and oxytocin, which the posterior pituitary releases into the blood. [1][2]
The 3D brain needs JavaScript. The text below still says where the supraoptic nucleus is and what it does.
Opens cut by a side (sagittal) slice through the hypothalamus, which holds the supraoptic 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 supraoptic nucleus is a small nucleus inside the base of the hypothalamus, next to the optic chiasm; 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 supraoptic nucleus — see it on its own page.
It sits at the base of the brain, just next to the optic chiasm, where the two optic nerves cross; “supraoptic” means above the optic (chiasm). [1]
In humans it holds about 3,000 neurons, which are large (magnocellular) and make very large amounts of their hormones. [1]
What it does
Its neurons make the peptide hormones vasopressin and oxytocin; both are released from the posterior pituitary. That hormone route is the hormones page’s posterior-pituitary step. [1][2]
Vasopressin (ADH) travels in the blood to the kidneys’ collecting (papillary) ducts and makes them take back more water; oxytocin acts on the uterus and the mammary glands. [1]
It answers the blood: vasopressin release rises when the blood is more concentrated or blood volume or pressure falls. [1]
Connections
Each neuron sends one long axon down the pituitary stalk to the posterior pituitary, where it ends in about 10,000 hormone-releasing terminals. Its inputs come mostly from neurons just around it, and from the brainstem (noradrenaline from the nucleus of the solitary tract and the medulla). [1]
The paraventricular nucleus, higher up beside the third ventricle, has the same kind of oxytocin- and vasopressin-making neurons; the subfornical organ and its neighbours on the third ventricle signal to both to control vasopressin release. [1][4]
Other names
Vasopressin is also called antidiuretic hormone (ADH) or arginine vasopressin. Textbooks often simplify the pair to “the supraoptic nuclei make ADH, the paraventricular nuclei oxytocin”; in fact both hold neurons making each hormone. [1][2][4]
Size
The model has no shape for the supraoptic 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.