Hypophyseal portal system (English)

The hypophyseal portal system is a network of blood vessels that allows the hypothalamus to exert control over the adenohypophysis via a system that allows the exchange and transport of hormones between the hypothalamus and adenohypophysis. The two primary arteries of the hypophyseal portal system are superior and inferior hypophyseal arteries, branches of the internal carotid artery. Branches of the superior hypophyseal artery form a primary capillary network located within the infundibulum and median eminence of the hypothalamus. The capillaries of this network receive hypothalamic hormones produced by the arcuate nucleus and other periventricular zone nuclei of the hypothalamus and merge together to form the long and short hypophyseal portal veins that travel to the adenohypophysis. These veins then divide again and form a secondary capillary network where the hormones carried from the hypothalamus stimulate or inhibit the release of anterior pituitary hormones. This forms a direct vascular pathway between the site where hypothalamic hormones are released (median eminence) and the endocrine cells of the adenohypophysis.