- Pituitary gland
Name = PAGENAME
Latin = hypophysis, glandula pituitaria
GraySubject = 275
GrayPage = 1275
Caption = Located at the base of the
brain, the pituitary gland is protected by a bony structure called the sella turcica(also known as turkish saddle)of the sphenoidbone.
Caption2 = Median sagittal through the hypophysis of an adult monkey. Semidiagrammatic.
Precursor = neural and oral
ectoderm, including Rathke's pouch
superior hypophyseal artery, infundibular artery, prechiasmal artery, inferior hypophyseal artery, capsular artery, artery of the inferior cavernous sinus[cite journal | author = Gibo H, Hokama M, Kyoshima K, Kobayashi S | title = [Arteries to the pituitary] | journal = Nippon Rinsho | volume = 51 | issue = 10 | pages = 2550–4 | year = 1993 | pmid = 8254920]
MeshName = Pituitary+Gland
MeshNumber = A06.407.747
DorlandsPre = h_22
DorlandsSuf = 12439692
The pituitary gland, or hypophysis, is an
endocrine glandabout the size of a pea. It is a protrusion off the bottom of the hypothalamusat the base of the brain, and rests in a small, bony cavity ( sella turcica) covered by a dural fold ( diaphragma sellae). The pituitary fossa, in which the pituitary gland sits, is situated in the sphenoidbone in the middle cranial fossaat the base of the brain.
The pituitary gland secretes
hormones regulating homeostasis, including tropic hormones that stimulate other endocrine glands. It is functionally connected to the hypothalamusby the median eminence.
Located at the base of the brain, the pituitary is functionally linked to the hypothalamus. It is composed of two lobes: the
adenohypophysisand neurohypophysis. The adenohypophysis, also referred to as the anterior pituitary is divided into anatomical regions known as the pars tuberalis, pars intermedia, and pars distalis. The neurohypophysis, also referred to as the posterior pituitary. The pituitary is functionally linked to the hypothalamus by the pituitary stalk, whereby hypothalamic releasing factors are released and in turn stimulate the release of pituitary hormones.
Anterior pituitary (Adenohypophysis)
anterior pituitarysynthesizes and secretes important endocrine hormones, such as ACTH, TSH, PRL, GH, endorphins, FSH, and LH. These hormones are released from the anterior pituitary under the influence of hypothalamus. Hypothalamic hormones are secreted to the anterior lobe by way of a special capillarysystem, called the hypothalamic-hypophyseal portal system.it is developed from dorsalwall of pharynx(stomodial part) i.e called as 'ruthke's pouch'. they all transport by special nerve cells present in the hypothalamus.such nerve cells are located in various parts of hypothalamus & send their nerve fibre into median eminence & tubar cinerium(b/w ant. &post. lobe).
Posterior pituitary (Neurohypophysis)
The hormones secreted by the posterior pituitary are
Oxytocin, where the majority is released from the paraventricular nucleusin the hypothalamus
Antidiuretic hormone(ADH, also known as vasopressinand AVP, arginine vasopressin), the majority of which is released from the supraoptic nucleusin the hypothalamus
Oxytocin is one of the few hormones to create a positive feedback loop. For example, uterine contractions stimulate the release of oxytocin from the posterior pituitary, which in turn increases uterine contractions. This positive feedback loop continues until the baby is born.
There is also an intermediate lobe in many animals. For instance in fish it is believed to control physiological colour change. In adult humans it is just a thin layer of cells between the anterior and posterior pituitary. The intermediate lobe produces
melanocyte-stimulating hormone(MSH), although this function is often (imprecisely) attributed to the anterior pituitary.
The pituitary hormones help control some of the following body processes:
* Some aspects of
pregnancyand childbirthincluding stimulation of uterine contractions during childbirth
Sex organfunctions in both women and men
* The conversion of food into
Waterand osmolarityregulation in the body
Disorders involving the pituitary gland include:
Head and neck anatomy
* [http://www.umm.edu/endocrin/pitgland.htm The Pituitary Gland, from the UMM Endocrinology Health Guide]
* [http://instruction.cvhs.okstate.edu/Histology/HistologyReference/HREndoframe.htm Oklahoma State, Endocrine System]
* Pituitary apoplexy mimicking pituitary abscess [http://www.ispub.com/ostia/index.php?xmlPrinter=true&xmlFilePath=journals/ijns/vol4n1/pituitary.xml]
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