Approximately what percentage of blood flow to the liver is supplied by the portal vein?

The portal vein plays a crucial role in supplying blood to the liver, and it is responsible for carrying a significant portion of the liver's blood flow. Approximately 70% to 80% of the liver's blood supply comes from the portal vein. This vein collects blood from the gastrointestinal tract and spleen, rich in nutrients and other substances that need to be processed by the liver.

The hepatic artery contributes the remaining blood flow, delivering oxygenated blood to the liver. Together, these two blood sources ensure that the liver receives adequate blood supply to perform its vital functions, such as metabolism, detoxification, and the synthesis of proteins.

Recognizing that the portal vein's contribution is approximately 70% to 80% is important for understanding liver physiology and the implications for various liver conditions that could affect blood flow.