where does the blood in the hepatic portal vein come from
pancreas spleen gastrointestinal tract gallbladder
title: Portal vein text: Portal vein The portal vein or hepatic portal vein is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents. Approximately 75% of total liver blood flow is through the portal vein, with the remainder coming from the hepatic artery proper. The blood leaves the liver to the heart in the hepatic veins. The portal vein is not a true vein, because it conducts blood to capillary beds in the liver and not directly to the heart. It is a major component of title: Portal vein text: lesser omentum, falciform ligament, and those draining the gallbladder wall. The portal vein and hepatic arteries form the liver's dual blood supply. Approximately 75% of hepatic blood flow is derived from the portal vein, while the remainder is from the hepatic arteries. Unlike most veins, the portal vein does not drain into the heart. Rather, it is part of a portal venous system that delivers venous blood into another capillary system, the hepatic sinusoids of the liver. In carrying venous blood from the gastrointestinal tract to the liver, the portal vein accomplishes two tasks: it supplies the liver with metabolic title: Portal vein text: the hepatic portal system, one of only two portal venous systems in the body – with the hypophyseal portal system being the other. The portal vein is usually formed by the confluence of the superior mesenteric and splenic veins and also receives blood from the inferior mesenteric, left and right gastric veins, and cystic veins. Conditions involving the portal vein cause considerable illness and death. An important example of such a condition is elevated blood pressure in the portal vein. This condition, called portal hypertension, is a major complication of cirrhosis. Measuring approximately 8 cm (3 inches) in adults, the title: Hepatic veins text: Hepatic veins In human anatomy, the hepatic veins are the veins that drain de-oxygenated blood from the liver into the inferior vena cava. There are usually three upper hepatic veins draining from the left, middle, and right parts of the liver. These are larger than the group of lower hepatic veins that can number from six to twenty. All of the hepatic veins drain into the inferior vena cava. They are one of two sets of veins connected to the liver, the others are the portal veins. The large hepatic veins arise from smaller veins found within the liver, and title: Portal venous system text: The final common pathway for transport of venous blood from spleen, pancreas, gallbladder and the abdominal portion of the gastrointestinal tract (with the exception of the inferior part of the anal canal and sigmoid colon) is through the "hepatic portal vein". This portal vein is formed by the union of the "superior mesenteric vein" and the "splenic vein" posterior to the neck of the pancreas at the level of vertebral body L1. Ascending towards the liver, the portal vein passes posterior to the superior part of the duodenum and enters the right margin of the lesser omentum. It is anterior