The liver is the major site of many basic metabolic functions and the cells (hepatocytes) appear relatively unspecialized, the archetypal animal cell of textbooks. Liver is one of the few human tissues to have some capacity to regenerate (see oval cells). Not only does the liver produce many of the plasma proteins but it is an important site for detoxification of drugs and other xenobiotics (see cytochrome P450; glutathione S transferases) and a major site of glycogen storage. Glycogen storage diseases have a serious impact on the function of liver and many other tissues (see also phosphorylase kinase). Kuppfer cells are important for removal of particles and effete erythrocytes from the circulation. Inflammation of the liver (hepatitis) can be caused by various viruses, and hepatitis B and C virus infection is a major risk factor for hepatocarcinoma. Chronic inflammation, often a result of excess alcohol intake, can lead to cirrhosis and fibrosis (see Ito cells). Markers of liver dysfunction include alanine aminotransferase and formiminotransferase-cyclodeaminase. Accumulation of various substances in the liver can also lead to cirrhosis (e.g. in haemochromatosis and Wilson's disease) and lipid accumulation in lipocytes can be a feature of dietary overload (as in production of foie gras). There are various disorders of the bile system, including Alagille's syndrome, primary sclerosing cholangitis, and Gilbert's syndrome. Some toxins (e.g. aflatoxins) particularly affect the liver. See Torres body.
Subjects: Medicine and Health.