• Chinese: 脾臟
• Czech: slezina
• Danish: milt, splen g Danish
• Dutch: milt
• Esperanto: lieno
• Finnish: perna
• French: rate
• German: Milz
• Greek: σπλήνα
• Hebrew: טחול
• Icelandic: milta
• Italian: milza
• Japanese: 脾臓
• Korean: 지라
• Norwegian: milt
• Persian: طحال
• Polish: śledziona
• Portuguese: baço
• Russian: селезёнка
• Slovene: vranica
• Spanish: bazo
• Swahili: wengu
• Swedish: mjälte

• Czech: splín

Derived terms

• splenectomy

The spleen is an organ found in all vertebrate animals. In humans, the spleen is located in the abdomen of the body, where it functions in the destruction of redundant red blood cells 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 infections.

Anatomy

The human spleen is located in the upper left part of the abdomen, behind the stomach and just below the diaphragm. In normal individuals this organ measures about 125 × 75 × 50 mm (5 × 3 × 2 inches) in size, with an average weight of 150 grams (5 oz).

The spleen consists of masses of lymphoid tissue of granular appearance located around fine terminal branches of veins and arteries. These vessels are connected by modified capillaries called splenic sinuses.

Approximately 10% of people have one or more accessory spleens. 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 (to understand their naming it helps to know that "lien" is an alternate 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.

Function

Other functions of the spleen are less prominent, especially in the healthy adult:

• Production of opsonins, 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. In horses roughly 50% of the red blood cells are stored there. The red blood cells can be released when needed 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 themselves with their own stored red blood cells to try to achieve the same effect, but the human heart is not equipped to handle the higher-viscosity blood.

Disorders

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

The word spleen comes from the Greek splēn. In Latin its name is lien.

In 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 Romantic literature (18th century). The connection between spleen (the organ) and melancholy (the temperament) comes from the humoral medicine of the ancient Greeks. One of the humours (body fluid) was the black 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 humoral view of the organ.

In 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 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 "splenetic" is used to describe a person in a foul mood.

In China, the spleen '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

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

Footnotes

External links

• - "The visceral surface of the 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"

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