The is an organ located in the abdomen, where it functions in the destruction of old
Red Blood Cells and holding a reservoir of blood. It is regarded as one of the centers of activity of the
Reticuloendothelial System (part of the
Immune System ). Until recently, the purpose of the spleen was not known. It is increasingly recognized that its absence leads to a predisposition to certain
Infection s.
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
Inch es) in size, with an average weight of 150 g (5
Oz. ).
The spleen is the largest
Organ derived from
Mesenchyme and lying in the
Mesentery . It consists of masses of
Lymphoid Tissue of granular appearance located around fine terminal branches of
Vein s and
Arteries . These vessels are connected by modified
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 (to understand their naming it helps to know that "lien" is an alternate
Root for "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 below:
Other functions of the spleen are less prominent, especially in the healthy adult:
- 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. In humans, however, the spleen does not function as a deposit of red blood cells, but instead it stores platelets in case of an emergency .1 These animals also have large hearts in relation to their body size to accommodate the higher-viscosity blood that results. 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.
Enlargement of the spleen is known as
Splenomegaly . It may be caused by
Sarcoidosis ,
Malaria ,
Infectious Mononucleosis ,
Bacterial Endocarditis ,
Leukemia ,
Pernicious Anaemia ,
Gaucher's Disease ,
Leishmaniasis ,
Hodgkin's disute splenomegaly includes a
Complete Blood Count with differential, platelet count, and
Reticulocyte and atypical lymphocyte counts to exclude hemolytic anemia and leukemia. Assessment of
IgM antibodies to viral capsid antigen (a rising
Titer ) is indicated to confirm
Epstein-Barr Virus or
Cytomegalovirus . Other infections should be excluded if these tests are negative.
The absence of a spleen predisposes to some
Septicaemia infections. Vaccination and antibiotic measures are discussed under
Asplenia .
- Some people Congenitally completely lack a spleen, although this is rare.
The word comes from the
Greek ''splēn''.
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 19th century England women in bad humour were said to be afflicted by spleen, or the vapours of 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.
In (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".
