The Pituitary Gland

Key points

• • The pituitary gland (hypophysis) is a pea-sized gland hanging from the base of the brain by a stalk, and sitting in a bony hollow called the sella turcica.
• • It has two parts of different origin: a front part (anterior pituitary) from Rathke's pouch, an upward growth of oral ectoderm, and a back part (posterior pituitary) from the brain.
• • The anterior pituitary makes several hormones that control other glands (thyroid, adrenal, gonads) and growth, released under the control of the hypothalamus.
• • The hypothalamus controls the anterior pituitary through a special set of portal blood vessels that carry releasing hormones down the stalk.
• • The posterior pituitary does not make hormones but stores and releases two that are made in the hypothalamus (antidiuretic hormone and oxytocin).
• • Because the gland lies just below the optic chiasma, a pituitary tumour can press on it and cause loss of the outer halves of both visual fields.