spleen

(noun)

A ductless vascular gland that destroys old red blood cells, removes debris from the bloodstream, acts as a reservoir of blood, and produces lymphocytes.

Related Terms

(noun)

In vertebrates, including humans, a ductless vascular gland, located in the left upper abdomen near the stomach, which destroys old red blood cells, removes debris from the bloodstream, acts as a reservoir of blood, and produces lymphocytes.

Related Terms

Examples of spleen in the following topics:

  • Ruptured Spleen

    • The spleen acts as a blood filter for the body and can rupture due to trauma.
    • The spleen, similar in structure to a large lymph node, acts as a blood filter.
    • The rupture of a normal spleen can be caused by trauma, such as a car accident.
    • In the past, this would routinely be treated with emergency surgery and possible removal of the spleen, but it is becoming more common to simply monitor the patient to make sure the bleeding stops by itself, and to allow the spleen to heal on its own.
    • Patients whose spleens have been removed must receive immunizations to help prevent infections such as pneumonia.

  • Spleen

    • Survival is possible without a spleen.
    • The spleen is the largest distinct organ of the lymphatic system.
    • The spleen is made up of two distinct tissue types:
    • Red pulp is the site of blood filtration in the spleen.
    • The primary function of the spleen is blood filtration.

  • Muscular Arteries

    • The splenic artery (lienal artery), the blood vessel that supplies oxygenated blood to the spleen, is an example of a muscular artery.
    • The splenic artery branches off to the stomach and pancreas before reaching the spleen and gives rise to arterioles that directly supply capillaries of these organs.
    • Transverse section of the human spleen showing the distribution of the splenic artery and its branches

  • Abdominopelvic Regions

    • The left upper quadrant is the location of the left portion of the liver, part of the stomach, the pancreas, left kidney, spleen, portions of the transverse and descending colon, and parts of the small intestine.
    • Most organs are part of multiple regions, including the gallbladder, duodenum, stomach, kidneys, spleen, small intestine and colon.
    • The left hypochondriac region contains part of the spleen, the left kidney, part of the stomach, the pancreas, and parts of the colon.
    • The epigastric (above stomach) region contains the majority of the stomach,  part of the liver, part of the pancreas, part of the duodenum, part of the spleen, and the adrenal glands.
    • The left lumbar region consists of the descending colon, the left kidney, and part of the spleen.

  • WBC Formation

    • As development progresses, blood formation occurs primarily in the spleen, liver, and lymph nodes .
    • However, maturation, activation, and some proliferation of lymphoid cells occurs in lymphoid organs (spleen, thymus, and lymph nodes).
    • In some cases, the liver, thymus, and spleen may resume their haematopoietic function if necessary.

  • Lymphoid Tissue

    • It is found mainly in the lymph nodes, but also in the lymphoid follicles in tonsils, Peyer's patches, spleen, adenoids, skin, and other areas associated with the mucosa-associated lymphoid tissue (MALT).
    • In addition to supporting B and T lymphocyte activation, other secondary lymphoid organs perform other unique functions, such as the spleen's ability to filter blood and the tonsil's ability to capture antigens in the upper respiratory tract.
    • The thymus and bone marrow are primary lymphoid tissue, while the lymph nodes, tonsils, and spleen are secondary lymphoid tissue.

  • Anatomy of the Pancreas

    • In teleosts, and a few other species (such as rabbits), there is no discrete pancreas at all, with pancreatic tissue being distributed diffusely across the mesentery and even within other nearby organs, such as the liver or spleen.
    • It lies in contact with the spleen.

  • Platelet Formation

    • Old platelets are destroyed by macrophage phagocytosis in the spleen and by Kupffer cells in the liver.
    • Up to 40% of platelets are stored in the spleen as a reserve, released when needed by sympathetically-induced splenic muscle contractions during severe injury.

  • The Liver and Gallbladder

    • The liver is supplied by two main blood vessels on its right lobe: the hepatic artery and the portal vein.The portal vein brings venous blood from the spleen, pancreas, and small intestine so that the liver can process the nutrients and byproducts of food digestion.

  • Anatomy of the Liver and Gallbladder

    • The hepatic artery carries blood from the aorta to the liver, whereas the portal vein carries blood containing digested nutrients from the entire gastrointestinal tract and also from the spleen and pancreas to the liver.