pituitary gland
a gland, pea-sized in humans, that lies at the base of the brain and is connected by a stalk (the infundibulum) to the hypothalamus. The pituitary gland is divided into an anterior and a posterior lobe, which differ in function. The anterior lobe (adenohypophysis) produces and secretes tropic hormones (i.e., thyroid-stimulating hormone, follicle-stimulating hormone, corticotropin, and luteinizing hormone), growth hormone, prolactin, and melanocyte-stimulating hormone in response to releasing hormones from the hypothalamus. The posterior lobe (neurohypophysis) secretes two hormones, vasopressin and oxytocin, which are synthesized in the hypothalamus and transported down axons in the infundibulum to the neurohypophysis in response to direct neural stimulation. The pituitary’s role particularly in secreting tropic hormones, which regulate the production of other hormones, has resulted in its designation as the “master gland of
the endocrine system.” Also called hypophysis; hypophysis cerebri.