What supplies 75% of the liver's blood supply?

The correct answer is the hepatic portal vein because it is responsible for delivering approximately 75% of the liver’s blood supply. This vein carries nutrient-rich blood from the gastrointestinal tract and spleen directly to the liver. This is crucial for the liver's function, as it processes nutrients, detoxifies harmful substances, and metabolizes drugs.

The hepatic artery, while it does supply blood to the liver, contributes about 25% of the total blood supply and is responsible for delivering oxygenated blood. The aorta provides systemic circulation but is not directly involved in supplying blood to the liver. The inferior vena cava is a major vein that carries deoxygenated blood from the lower body back to the heart, but it does not supply blood directly to the liver. Understanding the roles of these vessels helps clarify the liver's unique blood supply and its critical functions in metabolism and detoxification.