part_of part of part of overlaps Homo sapiens hepatic portal vein http://upload.wikimedia.org/wikipedia/commons/3/33/Gray591.png In humans A vein in the abdominal cavity that drains blood from the gastrointestinal tract and spleen. It is usually formed by the confluence of the superior mesenteric and splenic veins, and also receives blood from the inferior mesenteric, gastric, and cystic veins. The hepatic portal vein is a major component of the hepatic portal system, one of the main portal venous systems in the body. Conditions involving the hepatic portal vein cause considerable illness and death. An important example of such a condition is elevated blood pressure in the hepatic portal vein. This condition, called portal hypertension, is a major complication of cirrhosis worldwide. [WP,unvetted] portal vein liver hepatic portal system