accessory spleen

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.

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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.

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accessory spleen

n.

Any of the small globular masses of splenic tissue occasionally found in the area of the spleen, or in one of the peritoneal folds.

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accessory spleen

Etymology: L, accessus, extra; Gk, splen

small nodules of splenic tissue that may occur in the gastrosplenic ligament, greater omentum, or other visceral sites.

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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.

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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.

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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.

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accessory spleen

splen accessorius Any of a number of small aggregates or masses of encapsulated splenic tissue located adjacent to the spleen or along the gastrosplenic ligament. See Spleen.