Blood flow The liver receives blood from two sources. Oxygenated blood is supplied in the hepatic artery, a branch of the celiac trunk from the abdominal aorta. Venous blood from the entire gastrointestinal tract (containing nutrients from the intestines) is brought to the liver by the hepatic portal vein. On reaching the liver the portal vein divides into thousands of which pass in between the lobules and terminate in the sinusoids. The blood leaves the liver via a central vein in each lobule, which drains in the hepatic vein.

Summary of functions
Carbohydrate metabolism
Gluconeogenesis (the synthesis of glucose from certain amino acids, lactate or glycerol)
Glycogenolysis (the breakdown of glycogen into glucose) (muscle tissues can also do this)
Glycogenesis (the formation of glycogen from glucose)
Synthesis and secretion of bile required for emulsifying fats. Some of the bile drains directly into the duodenum, and some is stored in the gallbladder.
Breakdown of insulin and other hormones
Protein metabolism
Lipid metabolism:
Cholesterol synthesis
The production of triglycerides (fats)
Production of blood coagulation factors I (fibrinogen), II (prothrombin), V, VII, IX, X and XI, as well as protein C, protein S and antithrombin.
Break down of hemoglobin, creating metabolites that are added to bile as pigment (bilirubin and biliverdin).
Break down of toxic substances and most medicinal products in a process called drug metabolism.
Conversion of ammonia to urea.
Storage of many substances, including glucose in the form of glycogen, vitamin B12, iron, and copper.
Red blood cell production in the first trimester fetus. By the 32nd week of gestation, the bone marrow has almost completely taken over that task.
Immunological effects – the reticuloendothelial system of the liver contains many immunologically active cells, acting as a 'sieve' for antigens carried to it via the portal system.