Pituitary gland


Pituitary gland

Infobox Anatomy
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 sphenoid bone.



Caption2 = Median sagittal through the hypophysis of an adult monkey. Semidiagrammatic.
Precursor = neural and oral ectoderm, including Rathke's pouch
System =
Artery = 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]
Vein =
Nerve =
Lymph =
MeshName = Pituitary+Gland
MeshNumber = A06.407.747
DorlandsPre = h_22
DorlandsSuf = 12439692
The pituitary gland, or hypophysis, is an endocrine gland about the size of a pea. It is a protrusion off the bottom of the hypothalamus at 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 sphenoid bone in the middle cranial fossa at 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 hypothalamus by the median eminence.

ections

Located at the base of the brain, the pituitary is functionally linked to the hypothalamus. It is composed of two lobes: the adenohypophysis and 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)

:main|Anterior pituitaryThe anterior pituitary synthesizes 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 capillary system, 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 nucleus in the hypothalamus
*Antidiuretic hormone (ADH, also known as vasopressin and AVP, arginine vasopressin), the majority of which is released from the supraoptic nucleus in 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.

Intermediate lobe

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.

Functions

The pituitary hormones help control some of the following body processes:
* Growth
* Blood pressure
* Some aspects of pregnancy and childbirth including stimulation of uterine contractions during childbirth
* Breast milk production
* Sex organ functions in both women and men
* Thyroid gland function
* The conversion of food into energy (metabolism)
* Water and osmolarity regulation in the body

Pathology

Disorders involving the pituitary gland include:


=Additional

ee also

* Head and neck anatomy

References

External links

*
*
* [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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Look at other dictionaries:

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