Which vessel is the main venous conduit delivering nutrient-rich blood from the GI tract to the liver?

• A. Inferior vena cava
• B. Splenic vein
• C. Hepatic portal vein
• D. Superior mesenteric vein

Answer: (C)

Blood from the GI tract is routed through a portal system so nutrients and other substances can be processed by the liver before mixing with the general circulation. The main vessel that carries this nutrient-rich blood directly into the liver is the hepatic portal vein, formed by the joining of tributaries like the splenic vein and the superior mesenteric vein. The inferior vena cava returns systemic venous blood to the heart and does not deliver GI blood to the liver. The superior mesenteric vein drains the intestines and feeds into the hepatic portal vein, not directly into the heart. The splenic vein drains the spleen (and parts of the stomach/pancreas) and also feeds into the hepatic portal vein. So the hepatic portal vein is the primary conduit delivering GI-derived blood to the liver.