View source for Hypophyseal portal system

{{Infobox Vein |
  Name        = {{PAGENAME}} |
  Latin       = venae portales hypophysiales  |
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  Image       = Grays pituitary.png |
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  Image2      = |
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  DrainsFrom  = |
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  DorlandsPre = s_33 |
  DorlandsSuf = 12787512  |
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The '''hypophyseal portal system''' (or '''hypothalamo-hypophyseal portal system''') is the system of [[blood vessel]]s that link the [[hypothalamus]] and the [[anterior pituitary]] in the [[brain]]. 

It allows [[endocrine system|endocrine]] communication between the two structures. It is part of the [[hypothalamic-pituitary-adrenal axis]]. The [[anterior pituitary]] receives releasing and inhibitory [[hormones]] in the blood. Using these, the anterior pituitary is able to fulfill its function of regulating the other endocrine glands.

It is one three [[portal system of circulation|portal systems of circulation]] in the human body; that is, it involves two [[capillary|capillary beds]] connected in [[series]] by [[venule]]s. The others are the hepatic portal system and that in the kidneys.<ref>{{cite book |title=Human physiology: an integrated approach |authors=Dee Unglaub Silverthorn, William C. Ober |year=2007 |publisher=Pearson/Benjamin Cummings |location= |isbn=0805368493 |page=229 |url=http://books.google.com/books?ei=m_JyTLPpNoP6lweEjNH3Dg&ct=result&id=PuEgAQAAIAAJ&dq=human+portal+systems&q=there+are+three+portal+systems+in+the+body%3A+one+in+the+kidneys%2C+one+in+the+digestive+system%2C+and+this+one+in+the+brain#search_anchor}}</ref>

==Hormone transport==
Mechanism for hormone transport via hypothalamoportal vessels: 
*cells regulated by different nuclei in hypothalamus, i.e., [[neurons]] that release [[neurotransmitters]] as hormones in the connective link between the pituitary and the brain. Hypothalamic hormones stimulate the release of the respective hormone from the anterior pituitary gland.
*[[Ligand (biochemistry)|ligands]] (in this case, hormones released by the hypothalamus to activate hormone release from the anterior pituitary) are picked up by blood vessels then taken to anterior pituitary where they are broken down and released back into blood vessels
*before they are broken down, hypothalamoportal vessel acts as local route for blood flow directly from hypothalamus to anterior pituitary.

==External links==
* http://www.llu.edu/llu/medicine/anatomy/glossary/ans102_109.html#Q103
* http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/hypopit/anatomy.html

==References==
{{Reflist}}

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{{Veins of the head and neck}}
{{Endocrine system anatomy}}
[[Category:Central nervous system]]
[[Category:Cardiovascular system]]

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[[fr:Système vasculaire porte hypothalamo-hypophysaire]]
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