spleen

(redirected from spleenful)
Also found in: Dictionary, Thesaurus, Encyclopedia.
Related to spleenful: Splenitive

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)
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

(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]