Spleen
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{{Infobox Anatomy |
Name = Spleen |
Latin = splen, lien |
GraySubject = 278 |
GrayPage = 1282 |
Image = Illu spleen.jpg |
Caption = Spleen |
Image2 = Horse_spleen_laparoscopic.jpg |
Caption2 = [[Laparoscopic]] view of a horse's spleen (the purple and grey mottled organ) |
Precursor = [[Mesenchyme]] of [[dorsal mesogastrium]] |
System = |
Artery = [[Splenic artery]] |
Vein = [[Splenic vein]] |
Nerve = [[Splenic plexus]] |
Lymph = |
MeshName = Spleen |
MeshNumber = A10.549.700 |
DorlandsPre = s_19 |
DorlandsSuf = 12750780 |
}}
The '''spleen''' is an organ found in all [[vertebrate]] animals<ref name="all-vert">[http://www.daviddarling.info/encyclopedia/S/spleen.html Entry for spleen, Internet Encyclopedia of Science] </ref>. In humans, the spleen is located in the abdomen of the body, where it functions in the destruction of redundant [[red blood cell]]s and holds a reservoir of blood. It is regarded as one of the centers of activity of the [[reticuloendothelial system]] (part of the [[immune system]]). It is increasingly recognized that its absence leads to a predisposition to certain [[infection]]s.<ref name="certain-infec">{{cite journal
| last = Brender, MD
| first = Erin
| authorlink = Erin Brender, MD
| coauthors = [[Allison Burke, MA, illustrator|Richard M. Glass, MD, editor]]
| title = Spleen Patient Page
| journal = Journal of the American Medical Association
| volume = 294
| issue = 20
| pages = 2660
| publisher = American Medical Association
| date = [[2005-11-23-30]]
| url = http://jama.ama-assn.org/cgi/reprint/294/20/2660.pdf
| format = [[PDF]]
| accessdate = 2008-03-20 }}</ref>
== Anatomy ==
The [[human]] spleen is located in the upper left part of the [[abdomen]], behind the [[stomach]] and just below the [[diaphragm (anatomy)|diaphragm]]. In normal individuals this organ measures about 125 × 75 × 50 mm (5 × 3 × 2 [[inch]]es) in size, with an average weight of 150 grams (5 [[ounce|oz]]).
The spleen consists of masses of [[lymphoid]] [[biological tissue|tissue]] of granular appearance located around fine terminal branches of [[vein]]s and [[artery|arteries]]. These vessels are connected by modified [[capillary|capillaries]] called splenic sinuses.
Approximately 10% of people have one or more [[accessory spleen]]s. They may form near the [[hilum]] of the main spleen, the junction at which the splenic vessels enter and leave the organ.
There are several [[peritoneal]] [[ligaments]] that support the spleen<ref>{{NormanAnatomy|spleen}}</ref> (to understand their naming it helps to know that "lien" is an alternate [[root (linguistics)|root]] for "spleen")
* [[gastrolienal ligament]] (gastrosplenic) - connects stomach to spleen.
* [[lienorenal ligament]] (splenorenal) - connects spleen to kidney.
* [[phrenicocolic ligament]] - connects [[left colic flexure]] to the [[thoracic diaphragm]]. The middle connects to the spleen.
Cross sections of the spleen reveal a red soft surface which is divided into two types of pulp which correspond to the two most important functional roles of the spleen, summarized in the next section. <ref>{{BUHistology|07701loa}}</ref>
== Function ==
{| class="wikitable"
| '''Area''' || '''Function ''' || '''Composition'''
|-
| [[red pulp]] || Mechanical filtration. Removes unwanted materials from the blood, including old [[red blood cells]]. ||
* "[[Sinus (anatomy)|sinuses]]" (or "[[Sinusoid (blood vessel)|sinusoid]]s") which are filled with [[blood]]
* "[[splenic cords]]" of [[reticular fiber]]s
* "[[marginal zone]]" bordering on white pulp
|-
| [[white pulp]] || Helps fight infections. || Composed of nodules, called [[Malpighian corpuscle]]s. These are composed of:<BR>
* "[[lymphoid follicles]]" (or "follicles"), rich in [[B cell|B-lymphocytes]]
* "[[periarteriolar lymphoid sheaths]]" (PALS), rich in [[T cell|T-lymphocytes]]
|}
Other functions of the spleen are less prominent, especially in the healthy adult:
* Production of [[opsonin]]s, [[properdin]], and [[tuftsin]].
* Creation of [[red blood cells]]. While the [[bone marrow]] is the primary site of [[hematopoeisis]] in the adult, up until the fifth month of gestation, the spleen has important hematopoietic functions. After birth, erythropoietic functions cease except in some hematologic disorders. As a major lymphoid organ and a central player in the reticuloendothelial system the spleen retains the ability to produce lymphocytes and, as such, remains an hematopoietic organ.
* Storage of [[red blood cells]] and other formed elements. This is only valid for certain mammals, such as dogs and horses{{Fact|date=May 2008}}. In horses roughly 50% of the red blood cells are stored there. The red blood cells can be released when needed <!--
--><ref name="MSNBC2006-Carey">{{cite news | first=Bjorn | last=Carey | url=http://www.msnbc.msn.com/id/12648465/ | title=Horse science: What makes a Derby winner - Spleen acts as 'natural blood doper,' scientist says | work= MSNBC.com | publisher=Microsoft | date=May 5, 2006 | accessdate=2006-05-09}}</ref> These animals also have large hearts in relation to their body size to accommodate the higher-[[viscosity]] blood that results. In humans, however, the spleen does not function as a depository of red blood cells, but instead it stores [[platelets]] in case of an emergency. Some athletes have tried [[doping (sport)|doping]] themselves with their own stored red blood cells to try to achieve the same effect{{Fact|date=November 2007}}, but the human [[heart]] is not equipped to handle the higher-viscosity blood.
== Disorders ==
{{main|Splenic disease}}
Disorders include [[splenomegaly]], where the spleen is enlarged by various reasons. On the other hand, a lack of normal spleen function is called [[asplenia]].
== Etymology and cultural views==<!-- This section is linked from [[Gabriel Fauré]] -->
The word '''spleen''' comes from the [[Greek language|Greek]] ''splēn''. In [[Latin language|Latin]] its name is ''lien''.
In [[French language|French]], spleen refers to a state of pensive sadness or [[melancholy]]. It has been popularized by the poet [[Charles Baudelaire]] (1821–1867) but was already used before, in particular in the [[Romanticism|Romantic]] literature (18th century). The connection between ''spleen'' (the organ) and ''[[melancholy]]'' (the temperament) comes from the [[The four humours|humoral medicine]] of the [[ancient Greeks]]. One of the humours (body fluid) was the black [[Bile (biology)|bile]], secreted by the spleen organ and associated with melancholy. In contrast, the [[Talmud]] (tractate Berachoth 61b) refers to the spleen as the organ of [[laughter]], possibly suggesting a link with the [[Humourism|humoral]] view of the organ.
In [[German language|German]], the word "spleen", pronounced as in English, refers to a persisting somewhat eccentric (but not quite lunatic) idea or habit of a person; however the organ is called "Milz", (cognate with [[Old English language|Old English]] milte).
In eighteenth- and nineteenth-century England, women in bad humour were said to be afflicted by the spleen, or the vapours of the spleen. In modern English, "to vent one's spleen" means to vent one's [[anger]], e.g. by shouting, and can be applied to both males and females; similarly, the English term "[[wikt:splenetic|splenetic]]" is used to describe a person in a foul mood.
In [[China]], the spleen '[[wikt:脾|脾]] (pí)' counts as the seat of one's temperament and is thought to influence the individual's willpower. Analogous to "venting one's spleen", "發脾氣" is used as an expression for getting angry, although in the view of [[Traditional Chinese Medicine]], the view of "脾" does not correspond to the anatomical "spleen".
In chiropractic (meric chart) problems with the spleen relate to T8 (eighth thorasic vertebrea), a subluxation at T8 is associated with low energy and/or low immune system function.
In infants it is not very common for the spleen to destroy red blood cells faster than the liver can conjugate the [[bilirubin]]. The effect of this would be more bilirubin in the blood plasma.
==See also==
* [[marginal zone]]
==Additional images==
<gallery>
Image:Gray532.png|The celiac artery and its branches.
Image:Gray533.png|The celiac artery and its branches.
Image:Gray1039.png|Horizontal disposition of the peritoneum in the upper part of the abdomen.
Image:Gray1097.png|Transverse section through the middle of the first lumbar vertebra.
Image:Gray1098.png|The duodenum and pancreas.
image:Gray1188.png|The visceral surface of the spleen.
image:Gray1189.png|Transverse section of the spleen, showing the trabecular tissue and the splenic vein and its tributaries.
image:Gray1190.png|Transverse section of the human spleen, showing the distribution of the splenic artery and its branches.
image:Gray1192.png|Section of the spleen, showing the termination of the small bloodvessels.
image:Gray1226.png|Back of lumbar region, showing surface markings for kidneys, ureters, and spleen.
image:Gray1217.png|Side of thorax, showing surface markings for bones, lungs (purple), pleura (blue), and spleen (green).
Image:Illu lymphatic system.jpg|Lymphatic system
</gallery>
==Footnotes==
{{reflist}}
==External links==
{{Wiktionarypar|spleen}}
* {{SUNYAnatomyFigs|38|03|01}} - "The visceral surface of the spleen."
* {{SUNYAnatomyImage|7|8|81}}
* [http://www.britannica.com/eb/article-9069185/spleen "spleen"] from ''[[Encyclopedia Britannica Online]]''
* [http://www.kidshealth.org/PageManager.jsp?dn=familydoctor&lic=44&cat_id=20091&article_set=20543&ps=104] from "[[Spleen and Lymphatic System at Family Doctor.org]]"
* [http://www.nlm.nih.gov/medlineplus/spleendiseases.html] from "[[Medline Plus Spleen Diseases]]"
{{lymphatic_system}}
[[Category:Glands]]
[[Category:Abdomen]]
[[Category:Lymphatic system]]
[[Category:Cardiovascular system]]
[[Category:Hematology]]
[[Category:Horse anatomy]]
[[ar:طحال]]
[[bn:প্লীহা]]
[[bs:Slezena]]
[[bg:Слезка]]
[[ca:Melsa]]
[[cv:Сула]]
[[cs:Slezina]]
[[da:Milt]]
[[de:Milz]]
[[dv:ހުންކޮށި]]
[[et:Põrn]]
[[el:Σπλήνας]]
[[es:Bazo]]
[[eo:Lieno]]
[[fr:Rate]]
[[hr:Slezena]]
[[id:Limpa]]
[[is:Milta]]
[[it:Milza]]
[[he:טחול]]
[[pam:Lape]]
[[ka:ელენთა]]
[[la:Lien]]
[[lt:Blužnis]]
[[mk:Слезенка]]
[[ml:പ്ലീഹ]]
[[nl:Milt]]
[[ja:脾臓]]
[[no:Milt]]
[[nn:Milt]]
[[pag:Pali]]
[[pl:Śledziona]]
[[pt:Baço]]
[[ro:Splină]]
[[qu:K'ayrapin]]
[[ru:Селезёнка]]
[[scn:Mèusa]]
[[simple:Spleen]]
[[sk:Slezina]]
[[sl:Vranica]]
[[sr:Слезина]]
[[sh:Slezina]]
[[su:Kawaya]]
[[fi:Perna]]
[[sv:Mjälte]]
[[te:ప్లీహము]]
[[th:ม้าม]]
[[vi:Lách]]
[[tr:Dalak]]
[[zh-yue:脾]]
[[zh:脾脏]]