Anatomy of the Endocrine System (cont.)

Medical Author:

Stephen Kemp, MD, PhD

Medical Editor:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Pituitary Gland

The pituitary gland is located at the base of the brain beneath the hypothalamus and is no larger than a pea. It is often considered the most important part of the endocrine system because it produces hormones that control many functions of other endocrine glands. When the pituitary gland does not produce one or more of its hormones or not enough of them, it is called hypopituitarism.

The pituitary gland is divided into two parts: the anterior lobe and the posterior lobe. The anterior lobe produces the following hormones, which are regulated by the hypothalamus:

• Growth hormone: Stimulates growth of bone and tissue (growth hormone deficiency in children results in growth failure. Growth hormone deficiency in adults results in problems in maintaining proper amounts of body fat and muscle and bone mass. It is also involved in emotional well-being.)
• Thyroid-stimulating hormone (TSH): Stimulates the thyroid gland to produce thyroid hormones (A lack of thyroid hormones either because of a defect in the pituitary or the thyroid itself is called hypothyroidism.)
• Adrenocorticotropin hormone (ACTH): Stimulates the adrenal gland to produce several related steroid hormones
• Luteinizing hormone (LH) and follicle-stimulating hormone (FSH): Hormones that control sexual function and production of the sex steroids, estrogen and progesterone in females or testosterone in males
• Prolactin: Hormone that stimulates milk production in females

The posterior lobe produces the following hormones, which are not regulated by the hypothalamus:

• Antidiuretic hormone (vasopressin): Controls water loss by the kidneys
• Oxytocin: Contracts the uterus during childbirth and stimulates milk production

The hormones secreted by the posterior pituitary are actually produced in the brain and carried to the pituitary gland through nerves. They are stored in the pituitary gland.