Hypophyseal portal system (Latin)

The systematis portalis hypophysialis is a network of blood vessels (vasa sanguinea) that allows the hypothalamus to exert control over the adenohypophysis. This is done via a system that allows the exchange and transport of hormones between the hypothalamus and adenohypophysis. Branches of the a. hypophysialis superior form a rete capillare primarium located within the infundibulum and eminentia mediana hypothalami. The capillaries of this network receive hypothalamic hormones produced by the ncl. arcuatus and other ncll. periventriculares of the hypothalamus and merge together to form the long and short vv. portales hypophysiales that travel to the adenohypophysis. These veins then divide again and form a rete capillare secundarium, 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 (eminentia mediana) and the endocrine cells of the adenohypophysis.