Kupffer's cells remove microorganisms, aged blood cells, and foreign substances from the blood that rushes through the sinusoids. The hepatocyte layer surrounding each sinusoid is only 1 to 2 hepatocytes thick, allowing each cell to be in direct contact with sinusoidal blood. This allows the cells to efficiently clear the blood of specific compounds. At the periphery of each lobule are 5 to 7 portal triads. Each portal triad consists of a hepatic portal vein, a hepatic artery, and a bile duct.
Blood enters the liver at the hepatic artery and hepatic portal vein.
The hepatic artery carries oxygen from the aorta and lipids from the lymphatics to the liver, while the hepatic portal vein carries monosaccharides, amino acids, and other nutrients from the capillaries of the small intestines and digestive organs. The blood from the artery and vein flow into sinusoids, and then it is transported past Kupffer's cells and into the central vein. It maintains blood glucose level in the blood by adjusting glucose and glycogen level through glycogenesis, glycogenolysis, and gluconeogenesis. Protein metabolism also occurs within the liver with the synthesis of plasma proteins, and the production of ammonia through deamination of amino acids. The liver also acts as a warehouse to store essential vitamins and minerals.