The liver lobes are made up of microscopic units called lobules which are roughly hexagonal in shape.
These lobules comprise of rows of liver cells (hepatocytes) which radiate out from a central point. The hepatic cells are in close contact with blood-filled sinusoids and also lie adjacent to canaliculi into which bile is secreted.
Situated around the perimeter of the lobule are branches of the hepatic artery, hepatic portal vein and bile duct. These cluster together at the "corners" of the lobule forming what is called the portal triad. At the mid-point of the lobule is the central vein. Blood flows out of the sinusoids into the central vein and is transported out of the liver.