Figure 1.
The functional unit or lobule of the liver (aka. The hepatic acinus). At each corner of each lobule is a portal triad, which contains branches of the hepatic portal vein, hepatic artery, and biliary tree. At the center of each lobule is the centrilobular vein. The lobule has an oxygen concentration gradient across it, with zone 1 having the highest concentration and zone 3 the lowest.