spleen

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spleen

 [splēn]
a large glandlike but ductless organ in the upper part of the abdominal cavity on the left side, lateral to the cardiac end of the stomach. Called also lien. adj., adj splen´ic. It is the largest collection of reticuloendothelial cells in the body and is composed of spongelike tissue of two types: red pulp, which is the dark reddish brown substance filling the interspaces of the sinuses of the spleen, and white pulp, which consists of sheaths of lymphatic tissue surrounding the arteries of the spleen. It is enclosed in a dense capsule. In a normal adult the spleen is about 12.5 cm long and weighs about 140 to 210 g. After gastric digestion and in the presence of disease the spleen enlarges.



During fetal life the spleen and liver produce erythrocytes, but after birth that function is taken over by the bone marrow. However, if there is bone marrow failure, the spleen may again produce erythrocytes. In the normal adult the spleen is a reservoir for blood, and contains a high concentration of erythrocytes. In times of exertion, emotional stress, pregnancy, severe bleeding, carbon monoxide poisoning, or other occasions when the oxygen content of the blood must be increased, the spleen contracts rhythmically to release its store of erythrocytes into the bloodstream.

The spleen also acts to help keep the blood free of unwanted substances, including wastes and infecting organisms. The blood is delivered to it by the splenic artery, and passes through smaller branch arteries into a network of channels lined with leukocytes known as phagocytes (see reticuloendothelial system). These clear the blood of old erythrocytes, damaged cells, parasites, and other toxic or foreign substances. Hemoglobin from the removed red cells is temporarily stored.
accessory spleen a small mass of tissue elsewhere in the body, histologically and functionally identical with that composing the normal spleen.

spleen

(splēn), [TA]
A large, vascular lymphatic organ lying in the upper part of the abdominal cavity on the left side, between the stomach and diaphragm, composed of white and red pulp; the white consists of lymphoid nodules and diffuse lymphoid tissue; the red consists of venous sinusoids between which are splenic cords; the stroma of both red and white pulp is composed of reticular fibers and cells. A framework of fibroelastic trabeculae extending from the capsule conveys blood vessels to and from the splenic pulp. The spleen is a blood-forming organ in early life and later a storage organ for red corpuscles and platelets; because of the large number of macrophages present in the spleen it also acts as a blood filter, identifying and destroying effete erythrocytes as well as participating in the immune defense of the body.
Synonym(s): splen [TA], lien
[G. splēn]

spleen

(splēn) a large, glandlike organ situated in the upper left part of the abdominal cavity, lateral to the cardiac end of the stomach. Among its functions are the disintegration of erythrocytes and the setting free of hemoglobin, which the liver converts into bilirubin; the genesis of new erythrocytes during fetal life and in the newborn; serving as a blood reservoir; and production of lymphocytes and plasma cells.
accessory spleen  a connected or detached outlying portion, or exclave, of the spleen.
diffuse waxy spleen  amyloid degeneration of the spleen involving especially the coats of the venous sinuses and the reticulum of the organ.
floating spleen , movable spleen one displaced and abnormally movable.
sago spleen  one with amyloid infiltration, the malpighian corpuscles looking like grains of sand.
wandering spleen  floating s.
waxy spleen  a spleen affected with amyloid degeneration.

spleen

(splēn)
n.
1.
a. A large, highly vascular lymphoid organ, lying in the human body to the left of the stomach below the diaphragm, serving to store blood, disintegrate old blood cells, filter foreign substances from the blood, and produce lymphocytes.
b. A homologous organ or tissue in other vertebrates.
c. Obsolete This organ conceived as the seat of emotions or passions.
2. Ill temper: vent one's spleen.
3. Archaic Melancholy.
4. Obsolete A whim; a caprice.

spleen′y adj.

spleen

Etymology: Gk, splen
a soft, highly vascular, roughly ovoid organ situated between the stomach and the diaphragm in the left hypochondriac region of the body. It is considered part of the lymphatic system because it contains localized lymphatic nodules. It is dark purple and varies in shape in different individuals and within the same individual at different times. The precise function of the spleen has baffled physiologists for more than 100 years, but research indicates it performs various tasks, such as defense, hemopoiesis, blood storage, and destruction and recycling of red blood cells and platelets. The spleen also produces leukocytes, monocytes, lymphocytes, and plasma cells in response to an infectious agent. It produces red cells before birth and is believed to produce red cells after birth only in extreme and hemolytic anemia. If the body suffers severe hemorrhage, the spleen can contract and increase the blood volume from 350 mL to 550 mL in less than 60 seconds. In the adult the spleen is usually about 12 cm long, 7 cm wide, and 3 cm thick. Its weight increases from 17 g or less in the first year to about 170 g at 20 years of age, then slowly decreases to about 122 g at 75 to 80 years of age. The variation in the weight of adult spleens is 100 to 250 g and, in extreme cases, 50 to 400 g. The size of the spleen increases during and after digestion and often increases during illness. Compare thymus. splenic [splen′ik] , adj.
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Spleen

spleen

(splēn) [TA]
A large vascular lymphatic organ lying in the upper part of the abdominal cavity on the left side, between the stomach and diaphragm, composed of white and red pulp; the white consists of lymphatic nodules and diffuse lymphatic tissue; the red consists of venous sinusoids between which are splenic cords; the stroma of both red and white pulp is reticular fibers and cells. A framework of fibroelastic trabeculae extending from the capsule subdivides the structure into poorly defined lobules. It is a blood-forming organ in early life and later a storage organ for red corpuscles and platelets; because of the large number of macrophages, it also acts as a blood filter, both identifying and destroying effete erythrocytes.
Synonym(s): lien [TA] , splen [TA] .
[G. splēn]

spleen

A solid, dark purplish organ, lying high on the left side of the abdomen between the stomach and the left kidney. The spleen is the largest collection of lymph tissue in the body and contains a mass of pulpy material consisting mainly of LYMPHOCYTES, PHAGOCYTES and red blood cells. The spleen is the main blood filter, removing the products of breakdown of red blood cells and other foreign and unwanted semisolid material. It is a source of lymphocytes and a major site of antibody formation.

spleen

an important part of the MONONUCLEAR PHAGOCYTE SYSTEM made up of lymphoid tissue. It stores excess red blood cells, destroys old cells, and is capable of acting as a reservoir holding 20–30% of all blood cells. It produces LYMPHOCYTES and serves to regulate the volume of blood cells elsewhere in the blood system.

Spleen

An organ located at the left side of the stomach that acts as a reservoir for blood cells and produces lymphocytes and other products involved in fighting infection.

spleen

(splēn) [TA]
Large, vascular lymphatic organ lying in upper part of abdominal cavity on left side, between stomach and diaphragm, composed of white and red pulp; blood-forming organ in early life and later a storage organ for red corpuscles and platelets.
Synonym(s): lien.
[G. splēn]

spleen,

n a soft, highly vascular, roughly ovoid organ situated between the stomach and the diaphragm in the left hypochondriac region of the body. It is considered part of the lymphatic system.

spleen

a large lymphoid organ usually situated in the cranial part of the abdominal cavity on the left of the stomach. The spleen contains the largest collection of reticuloendothelial cells in the body. In ruminants the spleen is located on the left lateral wall of the reticulum and under the last two ribs on the left side. Called also lien.

accessory spleen
a small mass of tissue, histologically and functionally identical with that composing the normal spleen but found elsewhere in the body.
slaughter spleen
see slaughter spleen.
References in periodicals archive ?
Thymus and spleen were separated from each mouse and histopathological changes were observed.
Besides these, Chaudhari et al [9] & Sangeeta et al [13] observed heart-shaped spleens in 6.
The research team discovered that two kinds of T cells, CD4+ and CD8+, segregated into different zones of the spleen before an immune response took place in mice.
This study was conducted to assess the effect of whey proteins (WPs) on the spleen tissues of diabetic rats.
CT of congenital and acquired abnormalities of the spleen.
These morphologic and immunostaining features were indicative of the presence of an epidermoid cyst arising within an intrapancreatic accessory spleen.
There is minimal literature on pre-operative diagnosis of intrapancreatic accessory spleens (IPAS) with isolated case reports of confirmation on histology and immunohistochemical staining for CD3 and CD20 [8] to distinguish from adenocarcinoma of the pancreas.
We maintained the same general approach and ligated the splenic artery prior to mobilization of the spleen to avoid intra-operative bleeding.
We operated on 6 patients whose spleens weighed more than 500 g.
Sulfur mustard tissue distribution data from an Iranian soldier who died 7 days after inhalation and/or dermal exposure to sulfur mustard indicated distribution: brain > kidney > liver > spleen > lung (Drasch et al.