ABSTRACT
A portal circulation is one in which blood from the capillary bed of one organ structure drains into the capillary bed of another organ structure through a larger vessel, usually a vein or venule. Examples of such circulations include the hepatic portal, placental, hypothalamo-hypophyseal and renal circulations. The kidney is interesting because it contains portal circulations. The function of the portal circulations is to maximise the reabsorption of water and electrolytes filtered at the glomerulus. Examples of portal circulations include the hepatic portal, placental, hypothalamo-hypophyseal and renal circulation. The pituitary gland is a pea-shaped structure that lies within the sella turcica of the sphenoid bone. It is approximately 1-1.5 cm in diameter and is attached to the hypothalamus via the infundibulum. The pituitary gland is made up of two anatomically and functionally separate portions – the anterior pituitary and the posterior pituitary.
