The liver is the largest gland in the body; it is multifunctional. To understand the function of the liver it is necessary to understand the blood supply to the liver. It is supplied by the hepatic artery in the typical manner but it is the only digestive organ drained by the inferior vena cava. Other digestive organs such as the small intestine, parts of the large intestine, stomach and pancreas are drained by the hepatic portal system which takes the blood directly to the liver. Thus, the liver receives oxygen poor, nutrient rich blood from the hepatic portal system and oxygen rich blood from the hepatic artery.