The pituitary gland (hypophysis) is approximately the size of a pea (~1 cm diameter, ~0.5 g weight). Despite its small size, it is the 'master gland' — secreting numerous hormones (GH, TSH, ACTH, FSH, LH, prolactin, ADH, oxytocin) that regulate most other endocrine glands and many body functions. It is located at the base of the brain, attached to the hypothalamus by the infundibulum (pituitary stalk).