A small region of the brain located just beneath the thalamus making up the floor of the third cerebral ventricle, and also the lower region of the diencephalon. The pituitary gland is attached to the bottom of the hypothalamus by a slender stalk (the infundibulum) as shown in the figure below. It is responsible for regulating many physiological systems of the body, including hormones produced by the pituitary gland, body temperature, thirst, hunger, water balance, and sexual function. It is also closely connected with emotional activity and sleep, and functions as a center for the integration of hormonal and autonomic nervous system activity through its control of pituitary secretions.