noun, plural: pituitary glands
An endocrine gland situated off the bottom of the hypothalamus, and acts as the master gland of the endocrine system since it is responsible for the release of different hormones that regulate many physiological processes
The endocrine system is one of the biological systems of humans and other vertebrates. It is comprised of the endocrine glands, i.e. ductless glands that release hormones into the blood or the lymph. The pituitary gland is one of the various endocrine glands that are present in humans and other vertebrates. It is regarded as the master gland of the endocrine system. It is responsible for the release of different hormones that regulate growth and metabolism.
The pituitary gland is located off the bottom of the hypothalamus at the base of the brain, in the small recess of a bone (i.e. the hypophysial fossa of the sphenoid bone). It is surrounded by sella turcica (a small bony cavity) covered by diaphragm sellae (a dural fold). In humans, it has the size as that of a pea and weighs about 0.5 grams.
The pituitary gland consists of three lobes: anterior pituitary, pars intermedia, and posterior pituitary. The anterior pituitary releases hormones that regulate growth, reproduction, lactation, and stress. The hormone-secreting cells in the anterior pituitary are as follows:
- somatotrophs – cells that releases human growth hormone (somatotropin)
- corticotrophs – cells that release melanocyte-stimulating hormone (MSH), adrenocorticotropic hormone (ACTH), and lipotropin
- thyrotrophs – cells that release thyroid-stimulating hormone
- gonadotrophs – cells that release luteinizing hormone (LH) and follicle-stimulating hormone (FSH)
- lactotrophs – cells that release prolactin
The pars intermedia or the intermediate lobe of the pituitary gland secretes melanocyte-stimulating hormone (MSH).
The posterior pituitary, an extension of the hypothalamus, produces and release oxytocin and antidiuretic hormone (ADH).
The pituitary gland plays a role in the regulation of the following:
- blood pressure
- water balance and osmoregulation
- conversion of food into energy
- thyroid gland functions
- sex organ functions
- some aspects of pregnancy, childbirth, and breast milk production in females
Hypothalamus, a region in the brain, contains neurosecretory cells that release certain hormones that act on the anterior pituitary gland, stimulating the latter to secrete hormones that would influence other endocrine glands and organs.
- hypophysis (zoology)
- Hypophysis cerebri
- master gland
- pituitary body