- Anterior pituitary
Infobox Anatomy
Name = PAGENAME
Latin = lobus anterior hypophyseos
GraySubject = 275
GrayPage = 1275
Caption = Median sagittal through the hypophysis of an adult monkey. Semidiagrammatic.
Precursor =oral mucosa (Rathke's pouch )
System =
Artery = superior hypophyseal
Vein = hypophyseal
Nerve =
Lymph =
MeshName = Anterior+Pituitary+Gland
MeshNumber = A06.407.747.608
DorlandsPre = a_14
DorlandsSuf = 12111161
The anterior pituitary (also called the adenohypophysis, from Greek "adeno", "gland"; "hypo", "under"; "physis", "growth"; hence, "glandular undergrowth") comprises the anterior lobe of thepituitary gland and is part of theendocrine system . Unlike the posterior lobe, the anterior lobe is genuinely glandular, hence the root "adeno" in its name.Under the influence of the
hypothalamus , the anterior pituitary produces and secretes severalpeptide hormone s that regulate many physiological processes including stress,growth , andreproduction .Regions
The term "pars distalis" is sometimes used as a synonym for the anterior pituitary, but this is not quite correct. The anterior pituitary is usually divided into three regions:
*
pars distalis ("distal part") - the majority of the anterior pituitary
*pars tuberalis ("tubular part") - a sheath extending up from the pars distalis and wrapping around thepituitary stalk
*pars intermedia ("intermediate part") - sits between the bulk of the anterior pituitary and the posterior pituitary and is often very small in humansThe function of the tuberalis is not well characterized, and most of the rest of this article refers primarily to the distalis.
Embryology
Unlike the
posterior pituitary (pars nervosa), which originates from neuralectoderm , the anterior pituitary arises from aninvagination of the oralectoderm and forms theRathke's pouch .This differentiation is exhibited by the fact that while the
posterior pituitary merely secretes hormones produced in thehypothalamus (ADH andoxytocin ), the anterior pituitary actually produces its hormones, while being under control of thehypothalamus .Major hormones secreted
One mnemonic used to remember the hormones produced by the anterior pituitary is: FLAT PEG (FSH, LH, ACTH, TSH, Prolactin, Endorphins and GH).
Hypothalamic releasing and release-inhibiting factors
Hormone secretion from the anterior pituitary gland is regulated by hormones secreted by the
hypothalamus . Neuroendocrine neurons in the hypothalamus projectaxon s to themedian eminence , at the base of the brain. At this site, these neurons can release substances into small blood vessels that travel directly to the anterior pituitary gland (the hypothalamo-hypophysial portal vessels).
=Additionalee also
*
Tropic hormone s
*Pituitary adenoma
*Triple bolus test External links
*
* [http://www.med.unc.edu/embryo_images/unit-nervous/nerv_htms/nerv016a.htm Embryology at unc.edu]
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