Pituitary gland: is a pea-sized gland that sits at the base of the brain in a bony cavity called the sella turcica (latin for "Turkish saddle"). The pituitary gland is a critical gland of the body and the "master" regulator of many hormones. Upon receiving signals from the brain region called the hypothalamus, the pituitary releases hormones into the general circulation to act on bodily organs and the brain. The pituitary is composed of two distinct regions, the anterior pituitary and posterior pituitary, with each region producing unique classes of hormones.