Anterior pituitary
335177
225627414
2008-07-14T16:59:46Z
Arcadian
104523
Reverted edits by [[Special:Contributions/208.235.231.134|208.235.231.134]] ([[User talk:208.235.231.134|talk]]) to last version by Doceva
{{Infobox Anatomy |
Name = {{PAGENAME}} |
Latin = lobus anterior hypophyseos |
GraySubject = 275 |
GrayPage = 1275 |
Image = Gray1181.png |
Caption = Median sagittal through the hypophysis of an adult monkey. Semidiagrammatic. |
Precursor = [[oral mucosa]] ([[Rathke's pouch]]) |
System = |
Artery = |
Vein = |
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#Usage in human anatomy|anterior]] lobe of the [[pituitary gland]] and is part of the [[endocrine system]]. Unlike the [[posterior pituitary|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 several [[peptide hormone]]s that regulate many physiological processes including [[stress (medicine)|stress]], [[growth]], and [[reproduction]].
==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 the [[pituitary stalk]]
* [[pars intermedia]] ("intermediate part") - sits between the bulk of the anterior pituitary and the posterior pituitary and is often very small in humans
The 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 neural [[ectoderm]], the anterior pituitary arises from an [[invagination]] of the oral [[ectoderm]] and forms the [[Rathke's pouch]].
This differentiation is exhibited by the fact that while the [[posterior pituitary]] merely secretes hormones produced in the [[hypothalamus]] ([[antidiuretic hormone|ADH]] and [[oxytocin]]), the anterior pituitary actually produces its hormones, while being under control of the [[hypothalamus]].
==Major hormones secreted==
{| class="wikitable"
! Hormone
! Other names
! Symbol(s)
! Secretory cells (staining type)
! Target
! Effect
|-
| [[Adrenocorticotropic hormone]]
| Corticotropin
| ACTH
| [[Corticotrophs]] ([[Anterior pituitary basophil|basophil]])
| [[Adrenal gland]]
| Secretion of [[glucocorticoid]]s
|-
| [[Endorphin]]s
| -
| -
| -
| [[Opioid receptors|Opioid receptor]]
| Inhibit perception of pain
|-
| [[Follicle-stimulating hormone]]
| -
| FSH
| [[Gonadotroph]]s (basophil)
| [[Ovaries]], [[Testes]]
| Growth of [[reproductive system]]
|-
| [[Human growth hormone]]
| Somatotropin
| hGH, STH
| [[Somatotrophs]] ([[acidophil]])
| [[Liver]], [[adipose tissue]]
| Promotes growth; [[lipid]] & [[carbohydrate]] [[metabolism]]
|-
| [[Luteinizing hormone]]
| Lutropin
| LH, ICSH
| [[Gonadotroph]]s (basophil)
| [[Ovaries]], [[Testes]]
| [[Sex hormone]] production
|-
| [[Prolactin]]
| -
| PRL
| [[Lactotroph]]s, also known as [[Mammotrophs]] ([[acidophil]])
| [[Ovary|Ovaries]], [[mammary gland]]s
| Secretion of [[estrogen]]s/[[progesterone]]; [[milk]] production
|-
| [[Thyroid-stimulating hormone]]
| Thyrotropin
| TSH
| [[Thyrotrophs]] (basophil)
| [[Thyroid gland]]
| Secretion of [[thyroid hormone]]s
|}
==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 project [[axon]]s to the [[median 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).
{| class="wikitable"
! Name || Other Names || Abbreviations || Location || Function
|-
| [[Corticotropin-releasing hormone]] || Corticotropin-releasing factor, Corticoliberin || CRH, CRF || [[parvocellular]] neuroendocrine neurons in the [[paraventricular nucleus]] || with [[vasopressin]], stimulates secretion of [[Adrenocorticotropic hormone|ACTH]]
|-
| [[Dopamine]] || Prolactin-inhibiting hormone || DA, PIH || neuroendocrine neurons of the [[arcuate nucleus]] || inhibits secretion of [[prolactin]]
|-
| [[Gonadotropin-releasing hormone]] || Luteinising-hormone releasing hormone || GnRH, LHRH || neuroendocrine neurons in the [[medial preoptic nucleus|medial preoptic]] and [[arcuate nucleus|arcuate nuclei]] || stimulates secretion of [[Luteinizing hormone|LH]] and [[Follicle-stimulating hormone|FSH]]
|-
| [[Growth hormone-releasing hormone]] || Growth-hormone-releasing factor, somatocrinin || GHRH, GHRF, GRF || arcuate nucleus [[neuroendocrine]] neurons || stimulates secretion of [[growth hormone]]
|-
| [[Somatostatin]] || Growth hormone-inhibiting hormone, Somatotropin release-inhibiting factor || SS, GHIH, SRIF || neuroendocrine neurons of the [[periventricular nucleus]] || inhibits secretion of [[growth hormone]]
|-
| [[Thyrotropin-releasing hormone]] || Thyrotropin-releasing factor, Thyroliberin, Protirelin || TRH, TRF || parvocellular neuroendocrine neurons in the [[paraventricular nucleus|paraventricular]] and [[anterior hypothalamic nucleus|anterior hypothalamic nuclei]] || stimulates secretion of [[Thyroid-stimulating hormone|TSH]]
|-
| [[Vasopressin]] || Arginine vasopressin, Antidiuretic hormone, Argipressin || AVP, ADH || [[parvocellular]] neuroendocrine neurons in the [[paraventricular nucleus]] || with [[Corticotropin-releasing hormone]], stimulates secretion of [[Adrenocorticotropic hormone|ACTH]]
|}
==Additional images==
<gallery>
Image:Gray1180.png|The anterior pituitary is the anterior, [[gland]]ular lobe of the [[pituitary gland]].
Image:Nasennebenhöhlen.gif
</gallery>
==See also==
* [[Tropic hormone]]s
* [[Pituitary adenoma]]
* [[Triple bolus test]]
==External links==
* {{BUHistology|14002loa}}
* [http://www.med.unc.edu/embryo_images/unit-nervous/nerv_htms/nerv016a.htm Embryology at unc.edu]
{{pituitary gland}}
{{Diencephalon}}
[[Category:Endocrine system]]
[[Category:Head and neck]]
[[de:Adenohypophyse]]
[[es:Adenohipófisis]]
[[fr:Anté-hypophyse]]
[[pt:Adenohipófise]]
[[sq:Hormonet e pjesës së përparme të hipofizës]]
[[fi:Adenohypofyysi]]