Pituitary Gland

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Pituitary gland
From Wikipedia, the free encyclopedia
Pituitary gland|
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Located at the base of the brain, the pituitary gland is protected by a bony structure called the sella turcica of the sphenoid bone.| |
Median sagittal through the hypophysis of an adult monkey. Semidiagrammatic.| Latin| hypophysis, glandula pituitaria|
Gray's| subject #275 1275|
Artery| superior hypophyseal artery,infundibular artery,prechiasmal artery, inferior hypophyseal artery, capsular artery, artery of the inferior cavernous sinus[1]| Precursor| neural and oral ectoderm, including Rathke's pouch| MeSH| Pituitary+Gland|

Dorlands/Elsevier| Pituitary gland|
In vertebrate anatomy the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing 0.5 grams (0.018 oz) in humans. It is not a part of the brain. 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 is functionally connected to the hypothalamus by the median eminence via a small tube called the infundibular stem (Pituitary stalk). 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 nine hormones that regulate homeostasis. Contents  [hide]  * 1 Anatomy * 2 Embryology * 2.1 Anterior * 2.2 Posterior * 2.3 Intermediate lobe * 3 Functions * 4 Diseases involving the pituitary gland * 5 Additional images * 6 See also * 7 References * 8 External links| -------------------------------------------------

[edit]Anatomy
The pituitary gland is a pea-sized gland that sits in a protective bony enclosure called the sella turcica. It is composed of three lobes: anterior,intermediate, and posterior. In many animals, these three lobes are distinct. However, in humans, the intermediate lobe is but a few cell layers thick and indistinct; as a result, it is often considered part of the anterior pituitary. In all animals, the fleshy, glandular anterior pituitary is distinct from the neural composition of the posterior pituitary. It belongs to the diencephalon -------------------------------------------------

[edit]Embryology
[edit]Anterior
Main article: Anterior pituitary
The anterior pituitary arises from an invagination of the oral ectoderm and forms Rathke's pouch. This contrasts with the posterior pituitary, which originates from neuroectoderm. The anterior pituitary synthesizes and secretes the following important endocrine hormones: Somatotrophins:

* Growth hormone (also referred to as 'Human Growth Hormone', 'HGH' or 'GH' or somatotropin), released under influence of hypothalamic Growth Hormone-Releasing Hormone (GHRH); inhibited by hypothalamic Somatostatin Thyrotrophins:

* Thyroid-stimulating hormone (TSH), released under influence of hypothalamic Thyrotropin-Releasing Hormone (TRH) Corticotropins:
* Adrenocorticotropic hormone (ACTH), released under influence of hypothalamic Corticotropin-Releasing Hormone (CRH) * Beta-endorphin, released under influence of hypothalamic Corticotropin-Releasing Hormone (CRH)[2] Lactotrophins:

* Prolactin (PRL), also known as 'Luteotropic' hormone (LTH), whose release is inconsistently stimulated by hypothalamic TRH, oxytocin, vasopressin, vasoactive intestinal peptide, angiotensin II, neuropeptide Y, galanin, substance P, bombesin-like peptides (gastrin-releasing peptide, neuromedin B and C), and neurotensin, and inhibited by hypothalamic dopamine.[3] Gonadotropins:

* Luteinizing hormone (also referred to as 'Lutropin' or 'LH' or, in males, 'Interstitial Cell-Stimulating Hormone' (ICSH)) * Follicle-stimulating hormone (FSH), both released under influence of Gonadotropin-Releasing Hormone (GnRH) Melanotrophins

* Melanocyte–stimulating...
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