Hepatocytes are the liver cells. They are arranged to form a liver lobule, which is the functional unit of the liver. The liver lobule is a hexagonal shaped structure. At the angles of the liver lobule are portal triads. The portal triad is composed of a branch of the hepatic artery, portal vein, and bile duct. In the middle of the liver lobule is a central vein. Hepatic sinusoids run between the hepatocytes.