The portal vein, also known as the hepatic portal vein, is the only route of venous return to the digestive organs in the abdominal cavity. It passes through the portal vein and then enters the inferior vena cava via the intrahepatic hepatic vein. The portal vein generally has the following branches: 1. superior mesenteric vein. 2. splenic vein. 3. inferior mesenteric vein. 4. left gastric vein, coronary vein of the stomach. 5. right gastric vein. 6. gallbladder vein. 7. paraumbilical vein. The portal vein is of great physiological importance because it collects all the intra-abdominal venous reflux of unpaired organs, passes through the liver and detoxifies them and absorbs digestive substances.