The Pituitary Gland: Anatomy, Physiology, and its Function as the Master Gland

The pituitary gland, known as the "master gland," is involved in the homeostatic regulation of numerous body functions as well as in governing reproduction and childbirth. Found at the base of the skull, surrounded by cranial nerves and critical blood vessels, it is composed of the adenohypophysis and neurohypophysis. The adenohypophysis is controlled by the hypothalamus via releasing/inhibiting hormones released into the pituitary portal veins to secrete adrenocorticotropic hormone, thyroid-stimulating hormone, growth hormone, follicle-stimulating hormone, luteinizing hormone, and prolactin. These govern four major hormone systems: adrenal, thyroid, growth hormone, and reproduction/lactation. These systems are regulated by feedback loops from the effector hormones. The posterior pituitary gland is directly stimulated by the hypothalamus to produce vasopressin for fluid homeostasis and oxytocin for lactation and uterine contraction. Dysfunction or overactivity of any of these hormones can affect multiple organ systems. It is important to understand the normal anatomy and physiology of the pituitary gland to help diagnose and treat patients with pituitary disorders.