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Theories of Blood Circulation of Spleen

The spleen is an organ in the upper far left part of the abdomen, to the left of the stomach. It is a vital organ for the maintenance of bodily fluids balanced, but it is possible to live without it. It acts as a filter for blood as part of the immune system. It also helps fight certain kinds of bacteria that cause pneumonia and meningitis.

Splenic circulation – Blood flows into the spleen via the splenic artery which then branches into trabecular arteries.

The splenic artery divides into five or more branches on reaching the hilum. Within the spleen, it divides repeatedly to form successively straight vessels called penicillin, ellipsoids, and arterial capillaries. Further courses of blood are uncertain.

(1) According to ‘Closed’ theory

The capillaries are continuous with the venous sinusoids (that lie in red pulp). The sinusoids join together to form the veins. This theory proposes that blood empties from the capillary directly into the splenic sinus.

(2) According to the Open theory

The capillaries end by opening into the red pulp from where the blood enters the sinusoids through their walls. This theory proposes that blood empties into spaces between the reticular cells of the red pulp outside the sinus and then enters circulation through slits in the sinus wall

(3) According to ‘Compromise’ theory

Where the circulation is ‘open’ in the distended spleen and closed in the contracted spleen.