Adrenal cortex 270061 211536782 2008-05-10T21:34:26Z 194.82.51.28 {{Infobox Anatomy | Name = {{PAGENAME}} | Latin = cortex glandulae suprarenalis | GraySubject = 277 | GrayPage = 1278 | Image = Gray1185.png | Caption = Layers of cortex. | Image2 = | Caption2 = | Precursor = [[mesoderm]]<ref name="titleEmbryology of the adrenal gland">{{cite web |url=http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=endocrin.box.466 |title=Embryology of the adrenal gland |accessdate=2007-12-11 |format= |work=}}</ref> | System = | Artery = | Vein = | Nerve = | Lymph = | MeshName = | MeshNumber = | DorlandsPre = c_57 | DorlandsSuf = 12261690 | }} [[Image:Adrenal gland (cortex).JPG|thumb|200px|Cortical part of the adrenal gland (on the pointer).]] Situated along the perimeter of the [[adrenal gland]], the '''adrenal cortex''' mediates the stress response through the production of [[mineralocorticoid]]s and [[glucocorticoid]]s, including [[aldosterone]] and [[cortisol]] respectively. It is also a secondary site of [[androgen]] synthesis. ==Layers==<!-- This section is linked from [[Reticular layer]] --> The cortex can be divided into three distinct layers of [[biological tissue|tissue]] based on their organisation. A useful mnemonic, GFR, relates to the glomerular filtration rate, as used in [[Glomerular filtration rate|clinical practice]]. {| class="wikitable" | '''Layer''' || '''Name''' || '''Primary product''' |- | Most superficial cortical layer || [[zona glomerulosa]] || [[mineralocorticoid]]s (eg, [[aldosterone]]) |- | Middle cortical layer || [[zona fasciculata]] || [[glucocorticoid]]s (eg, [[cortisol]]) |- | Deepest cortical layer || [[zona reticularis]] || weak [[androgen]]s (eg, [[dehydroepiandrosterone]]) |} ==Steps of hormone synthesis== * All adrenocortical hormones are synthesised from [[cholesterol]]. * [[Cholesterol]] is transported into the [[inner mitochondrial membrane]] by [[steroidogenic acute regulatory protein]] ({{Gene|STAR}}), where it is converted into [[pregnenolone]] by the enzyme {{Gene|CYP11A1}}. Accordingly, production of hormones in all three layers of the adrenal cortex is limited by the transportation of cholesterol into the [[mitochondria]] and by its conversion into pregnenolone. * Pregnenolone can be either [[dehydrogenated]] to [[progesterone]], or [[hydroxylated]] to [[17-alpha-hydroxypregnenolone]]. The steps up to this point occur in many [[steroid]]-producing tissues. Subsequent steps, however, only occur in the adrenal cortex: * Progesterone → (hydroxylation at C21) → [[Deoxycorticosterone]] → (two further hydroxylations) → [[Aldosterone]] * Progesterone → (hydroxylation at C17) → 17-alpha-hydroxyprogesterone → (hydroxylation) → [[Deoxycortisol]] → (hydroxylation) → [[Cortisol]] ==Production== The adrenal cortex produces a number of different [[corticosteroid]] [[hormone]]s: *[[Mineralocorticoids]]: They are produced in the [[zona glomerulosa]]. The primary [[mineralocorticoid]] is [[aldosterone]]. Its secretion is regulated by the [[oligopeptide]] [[angiotensin II]] (angiotensin II is regulated by [[angiotensin I]], which in turn is regulated by [[renin]]). Aldosterone is secreted in response to high [[extracellular]] [[potassium]] levels, low extracellular [[sodium]] levels, and low fluid levels and blood volume. Aldosterone affects [[metabolism]] in different ways: **It increases [[urine|urinary]] excretion of potassium [[ions]] **It increases interstitial levels of sodium ions **It increases water retention and blood volume *[[Glucocorticoids]]: They are produced in the [[zona fasciculata]]. The primary glucocorticoid released by the adrenal gland is [[cortisol]]. Its secretion is regulated by the hormone [[Adrenocorticotropic hormone|ACTH]] from the [[anterior pituitary]]. Upon binding to its target, cortisol enhances [[metabolism]] in several ways: **It stimulates the release of [[amino acid]]s from the body **It stimulates [[lipolysis]], the breakdown of [[fat]] **It stimulates [[gluconeogenesis]], the production of [[glucose]] from newly-released amino acids and [[lipid]]s **It increases blood glucose levels in response to stress, by inhibiting glucose uptake into [[muscle cells|muscle]] and [[adipose tissue|fat cells]] **It strengthens [[cardiac muscle]] contractions **It increases water retention **It has anti-inflammatory and anti-allergic effects *[[Androgens]]: They are produced in the [[zona reticularis]]. The most important androgens include: **[[Testosterone]]: a hormone with a wide variety of effects, ranging from enhancing muscle mass and stimulation of [[cell growth]] to the development of the [[secondary sex characteristic]]s. **[[Dihydrotestosterone]] (DHT): a [[metabolism|metabolite]] of testosterone, and a more potent androgen than testosterone in that it binds more strongly to androgen receptors. **[[Androstenedione]] (Andro): an androgenic steroid produced by the [[testes]], adrenal cortex, and [[ovaries]]. While [[androstenedione]]s are converted metabolically to testosterone and other [[androgen]]s, they are also the parent structure of [[estrone]]. **[[Dehydroepiandrosterone]] (DHEA): a steroid hormone produced from [[cholesterol]]. It is the primary precursor of natural [[estrogen]]s. DHEA is also called [[dehydroisoandrosterone]] or [[dehydroandrosterone]]. ==Pathology== * [[Adrenal insufficiency]] (e.g. due to [[Addison's disease]]) * [[Cushing's syndrome]] * [[Congenital adrenal hyperplasia]] * [[Conn's syndrome]] ==See also== * [[Adrenal gland]] ==References== {{Refimprove|date=December 2007}} {{reflist}} ==External links== * {{SUNYAnatomyLabs|40|04|02|03}} - "Posterior Abdominal Wall: Blood Supply to the Suprarenal Glands" * {{MedicalMnemonics|180|2201|412|}} * {{BUHistology|14502loa}} * {{AnatomyAtlasesMicroscopic|15|292}} - "Adrenal Gland" * [http://www.rahulgladwin.com/blog/2007/02/functions-of-adrenal-cortex.html Adrenal Cortex Medical Notes on rahulgladwin.com] {{Adrenal gland}} [[Category:Glands]] [[Category:Abdomen]] [[Category:Endocrine system]] [[de:Nebenniere#Nebennierenrinde]] [[pl:Kora nadnerczy]] [[pt:Córtex adrenal]]