Spleen

Source: Wikipedia, the free encyclopedia.
(Redirected from
Splenic hilum
)
For other uses, see Spleen (disambiguation).
This article uses anatomical terminology.
Spleen
Position of the human spleen
Details
SystemImmune system (Lymphatic system)
ArterySplenic artery
VeinSplenic vein
NerveSplenic plexus
Identifiers
Latinsplen, lien
MeSHD013154
TA98A13.2.01.001
TA25159
FMA7196
Anatomical terminology
3D medical animation still showing structure of as well as location of the spleen in human body
A 3D medical animation still of spleen structure and exact location

The spleen is an

Ancient Greek σπλήν (splḗn).[1]

The spleen plays very important roles in regard to

senescent red blood cells. The globin portion of hemoglobin is degraded to its constitutive amino acids, and the heme portion is metabolized to bilirubin, which is removed in the liver.[3][4]

The spleen houses

monocytes which remove antibody-coated bacteria and antibody-coated blood cells by way of blood and lymph node circulation. These monocytes, upon moving to injured tissue (such as the heart after myocardial infarction), turn into dendritic cells and macrophages while promoting tissue healing.[5][6][7] The spleen is a center of activity of the mononuclear phagocyte system and is analogous to a large lymph node, as its absence causes a predisposition to certain infections.[8][4]

In humans, the spleen is purple in color and is in the

left upper quadrant of the abdomen.[3][9] The surgical process to remove the spleen is known as a splenectomy
.

Structure

The spleen is underneath the left part of the diaphragm, and has a smooth, convex surface that faces the diaphragm. It is underneath the ninth, tenth, and eleventh ribs. The other side of the spleen is divided by a ridge into two regions: an anterior gastric portion, and a posterior renal portion. The gastric surface is directed forward, upward, and toward the middle, is broad and concave, and is in contact with the posterior wall of the stomach. Below this it is in contact with the tail of the pancreas. The renal surface is directed medialward and downward. It is somewhat flattened, considerably narrower than the gastric surface, and is in relation with the upper part of the anterior surface of the left kidney and occasionally with the left adrenal gland.

There are four ligaments attached to the spleen: gastrosplenic ligament, splenorenal ligament, colicosplenic ligament, and phrenocolic ligament.[10]

Measurements

90% confidence interval of spleen length by abdominal ultrasonography by height of the person[11]
Height Spleen length
Women Men
155–159 cm 6.4–12 cm
160–164 cm 7.4–12.2 cm 8.9–11.3 cm
165–169 cm 7.5–11.9 cm 8.5–12.5 cm
170–174 cm 8.3–13.0 cm 8.6–13.1 cm
175–179 cm 8.1–12.3 cm 8.6–13.4 cm
180–184 cm 9.3–13.4 cm
185–189 cm 9.3–13.6 cm
190–194 cm 9.7–14.3 cm
195–199 cm 10.2–14.4 cm

The spleen, in healthy adult humans, is approximately 7 to 14 centimetres (3 to 5+1⁄2 in) in length.

An easy way to remember the anatomy of the spleen is the 1×3×5×7×9×10×11 rule. The spleen is 1 by 3 by 5 inches (3 by 8 by 13 cm), weighs approximately 7 oz (200 g), and lies between the 9th and 11th ribs on the left-hand side and along the axis of the 10th rib. The weight varies between 1 oz (28 g) and 8 oz (230 g) (standard reference range),[12] correlating mainly to height, body weight and degree of acute congestion but not to sex or age.[13]

  • Spleen seen on abdominal ultrasonography
    Spleen seen on abdominal ultrasonography
  • Maximum length of spleen on abdominal ultrasonography
    Maximum length of spleen on abdominal ultrasonography
  • Back of lumbar region, showing surface markings for kidneys, ureters, and spleen
    Back of lumbar region, showing surface markings for kidneys, ureters, and spleen
  • Side of thorax, showing surface markings for bones, lungs (purple), pleura (blue), and spleen (green)
    Side of thorax, showing surface markings for bones, lungs (purple), pleura (blue), and spleen (green)

Blood supply

Visceral surface of the spleen

Near the middle of the spleen is a long fissure, the hilum, which is the point of attachment for the gastrosplenic ligament and the point of insertion for the splenic artery and splenic vein. There are other openings present for lymphatic vessels and nerves. In addition to the splenic artery, collateral blood supply is provided by the adjacent short gastric arteries.[14]

Like the

efferent lymphatic vessels. The spleen is part of the lymphatic system. Both the short gastric arteries and the splenic artery supply it with blood.[15]

The germinal centers are supplied by arterioles called penicilliary radicles.[16]

Nerve supply

The spleen is innervated by the splenic plexus, which connects a branch of the celiac ganglia to the vagus nerve.

The underlying central nervous processes coordinating the spleen's function seem to be embedded into the Hypothalamic-pituitary-adrenal-axis, and the brainstem, especially the subfornical organ.[17]

Development

The spleen is unique in respect to its development within the

celiac trunk—as the foregut
organs.

Function

Pulp

Micrograph of splenic tissue showing the red pulp (red), white pulp (blue) and a thickened inflamed capsule (mostly pink – top of image). H&E stain.
The spleen contains two different tissues, white pulp (A) and red pulp (B). The white pulp functions in producing and growing immune and blood cells. The red pulp functions in filtering blood of antigens, microorganisms, and defective or worn-out red blood cells.
Area Function Composition
red pulp Mechanical filtration of red blood cells. In mice: Reserve of monocytes[5]
white pulp Active immune response through humoral and cell-mediated pathways. Composed of nodules, called Malpighian corpuscles. These are composed of:

Other

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

Clinical significance

Surgically removed spleen of a child with thalassemia. It is about 15 times larger than normal.
Thalassemia enlarged spleen taken after splenectomy

Enlarged spleen

Main article: Splenomegaly

Enlargement of the spleen is known as

tumours. Primary tumors of the spleen include hemangiomas and hemangiosarcomas
. Marked splenomegaly may result in the spleen occupying a large portion of the left side of the abdomen.

The spleen is the largest collection of

neonates, and in 5% to 10% of infants and toddlers. A spleen easily palpable below the costal margin
in any child over the age of 3–4 years should be considered abnormal until proven otherwise.

Splenomegaly can result from antigenic stimulation (e.g., infection), obstruction of blood flow (e.g., portal vein obstruction), underlying functional abnormality (e.g.,

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.

Splenic injury

Main article: Splenic injury

rupture of the spleen
, which is a situation requiring immediate medical attention.

Asplenia

Main article: Asplenia

polysaccharide encapsulated bacteria. Encapsulated bacteria inhibit binding of complement or prevent complement assembled on the capsule from interacting with macrophage receptors. Phagocytosis needs natural antibodies, which are immunoglobulins that facilitate phagocytosis either directly or by complement deposition on the capsule. They are produced by IgM memory B cells (a subtype of B cells) in the marginal zone of the spleen.[23][24]

A

ischemic heart disease (41 rather than the expected 30), but not from other conditions.[26]

Accessory spleen

An

trauma or splenectomy) autotransplant in the abdominal cavity as accessory spleens.[28]

Polysplenia is a congenital disease manifested by multiple small accessory spleens,[29] rather than a single, full-sized, normal spleen. Polysplenia sometimes occurs alone, but it is often accompanied by other developmental abnormalities such as intestinal malrotation or biliary atresia, or cardiac abnormalities, such as dextrocardia. These accessory spleens are non-functional.

Infarction

Main article: Splenic infarction

Splenic infarction is a condition in which blood flow supply to the spleen is compromised,[30] leading to partial or complete infarction (tissue death due to oxygen shortage) in the organ.[31]

Splenic infarction occurs when the

left upper quadrant of the abdomen, sometimes radiating to the left shoulder. Fever and chills develop in some cases.[32] It has to be differentiated from other causes of acute abdomen
.

Hyaloserositis

The spleen may be affected by hyaloserositis, in which it is coated with fibrous hyaline.[33][34]

Society and culture

There has been a long and varied history of misconceptions regarding the physiological role of the spleen, and it has often been seen as a reservoir for juices closely linked to digestion.

a key organ that displays the Yin aspect of the Earth element (its Yang counterpart is the stomach). In contrast, the Talmud (tractate Berachoth 61b) refers to the spleen as the organ of laughter
while possibly suggesting a link with the humoral view of the organ.

Etymologically, spleen comes from the

the heart in modern English. Persius, in his satires, associated spleen with immoderate laughter.[36]

In English, William Shakespeare frequently used the word spleen to signify melancholy, but also caprice and merriment.[36] In Julius Caesar, he uses the spleen to describe Cassius's irritable nature:

Must I observe you? must I stand and crouch
Under your testy humour? By the gods
You shall digest the venom of your spleen,
Though it do split you; for, from this day forth,
I'll use you for my mirth, yea, for my laughter,
When you are waspish.[37]

The spleen, as a byword for melancholy, has also been considered an actual disease.

the vapours", while preferring the more learned terms "hypochondriasis" and "hysteria".[38][40][41] In the late 18th century, the German word Spleen came to denote eccentric and hypochondriac tendencies that were thought to be characteristic of English people.[36]

In

19th-century Romantic literature
.

Food

The spleen is one of the many organs that may be included in offal. It is not widely eaten as a principal ingredient, but cow spleen sandwiches are eaten in Sicilian cuisine.[42] Chicken spleen is one of the main ingredients of Jerusalem mixed grill.[43]

Other animals

Laparoscopic
view of a horse's spleen (the purple and grey mottled organ)

In

intestine. In many amphibians, especially frogs, it has the more rounded form and there is often a greater quantity of white pulp.[44]

In

cetaceans and manatees they tend to be quite small, but in deep diving pinnipeds
, they can be massive, due to their function of storing red blood cells.

Marsupials have y-shaped spleens, and it develops postnatally.[45][46][47][48]

The only vertebrates lacking a spleen are the

jawless fishes). Even in these animals, there is a diffuse layer of haematopoeitic tissue within the gut wall, which has a similar structure to red pulp and is presumed homologous with the spleen of higher vertebrates.[44]

In mice, the spleen stores half the body's monocytes so that, upon injury, they can migrate to the injured tissue and transform into dendritic cells and macrophages to assist wound healing.[5]

Additional images

  • Transverse section of the spleen, showing the trabecular tissue and the splenic vein and its tributaries
    Transverse section of the spleen, showing the trabecular tissue and the splenic vein and its tributaries
  • Spleen
    Spleen
  • Laparoscopic view of human spleen
    Laparoscopic view of human spleen

See also

References

  1. OCLC 13606128
    – via Perseus Digital Library.
  2. PMID 30725992
    , retrieved 2022-12-04
  3. ^
    S2CID 3258595
    .
  4. ^
    PMID 35000931
    .
  5. ^
    PMID 19644120
    .
  6. ^
    PMID 19644100
    .
  7. ^ "Finally, the Spleen Gets Some Respect" By Natalie Angier, The New York Times, August 3, 2009
  8. PMID 16304080
    .
  9. ISBN 978-0-07-146633-2
    .
  10. S2CID 35213355
    .
  11. PMID 26509293
    .
  12. S2CID 32174574
    .
  13. PMID 9291593
    .
  14. S2CID 29302459
    .
  15. ISBN 978-0-7817-7076-7
    .
  16. ^ "Penicilliary radicles". Medical-dictionary.thefreedictionary.com. Retrieved 2011-04-03.
  17. PMID 28590409
    .
  18. S2CID 19864892
    .
  19. ^ "Rapid neutrophil mobilization by VCAM-1+ endothelial cell-derived extracellular vesicles | Cardiovascular Research | Oxford Academic". Academic.oup.com. Retrieved 2022-02-15.
  20. ^ Carey, Bjorn (May 5, 2006). "Horse science: What makes a Derby winner – Spleen acts as a 'natural blood doper,' scientist says". NBC News. Retrieved 2006-05-09.
  21. ^ "Spleen: Information, Surgery and Functions". Chp.edu. Childrens Hospital of Pittsburgh. 2010-11-17. Archived from the original on 2011-09-26. Retrieved 2011-04-03.
  22. PMID 20540444
    .
  23. S2CID 30554953
    .
  24. S2CID 20654498
    .
  25. PMID 12682112
    .
  26. S2CID 38605411
    .
  27. ISBN 978-0-683-06133-8
    .
  28. PMID 19123935
    .
  29. ^ "polysplenia" at Dorland's Medical Dictionary
  30. PMID 28613652
    , retrieved 2019-02-27
  31. PMID 3764696
    .
  32. PMID 9486895.{{cite journal}}: CS1 maint: numeric names: authors list (link
    )
  33. ^ "Hyaloserositis". Online Medical Dictionary. Accessed on: June 21, 2008.
  34. ^ "Sugar-coated spleen". Drugs.com.
  35. ^
    S2CID 172137672
    .
  36. ^
    ISBN 978-3-11-091260-9
    .
  37. ^ Julius Caesar by William Shakespeare Act 4:1
  38. ^
    S2CID 33529100
    .
  39. JSTOR 24780450
    .
  40. ISBN 978-0-8201-1281-7
  41. ^ Blackmore, Richard: Treatise of the spleen and vapors. London, 1725
  42. ^ Rao, Tejal (2010-05-03). "Spleen Sandwiches: An Italian Tradition". The Atlantic. Retrieved 2022-01-03.
  43. ^ Rogov, Daniel (2007-03-22). "Dining Out / Mixed Jerusalem grill in Tel Aviv". Haaretz. Retrieved 2022-01-03.
  44. ^
    ISBN 978-0-03-910284-5
    .
  45. PMC 1571326
    .
  46. doi:10.1016/j.dci.2003.08.004
    .
  47. PMC 1571326
    .
  48. PMC 1571143
    .

External links

Look up spleen in Wiktionary, the free dictionary.
Wikimedia Commons has media related to Spleen.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Spleen&oldid=1220351865#Structure"