Sunday, January 17 (2021); Cardiovascular system
The liver has a dual blood supply, receiving most of its blood flow (75%) as deoxygenated blood from the portal vein, and the rest from the hepatic artery. The portal vein is a low-pressure system of valveless vessels which does not autoregulate according to hepatic oxygen demand, but rather according to supply (eg. with meals, the portal vein dilates and increases its flow). The hepatic artery, apart from beign subject to normal arterial autoregulatory mechanisms, is also able to adjust its flow to compensate for changes in portal venous flow - a phenomenon known as the hepatic arterial buffer response.