Liver

Function

The liver is the body's chemical factory — 1.5 kg of metabolic machinery performing over 500 identified functions. It filters 1.4 L of blood per minute (75% portal venous, 25% hepatic arterial), and its hexagonal lobules process everything absorbed from the gut: it stores glycogen, builds plasma proteins and most clotting factors (factor VIII is made mainly by the liver's sinusoidal endothelial cells), detoxifies drugs and ammonia, makes bile and holds 10–15% of total blood volume as the circulation's buffer.

Uniquely among organs it regenerates — 70% resection is survivable as the remnant rebuilds within weeks, a capacity that makes living-donor transplantation possible. Its zonation is pharmacologically real: periportal hepatocytes excel at gluconeogenesis, pericentral at detoxification and glycolysis.

Blood supply

Hepatic artery proper (25%) and portal vein (75%); hepatic veins drain to the IVC.

Nerve supply

Sympathetic from the coeliac plexus; vagal parasympathetic; afferent via the right phrenic nerve (liver pain refers to the right shoulder).

Clinical relevance

Cirrhosis

Fibrotic scarring from alcohol, viral hepatitis or fatty liver disease shunts blood through portosystemic collaterals — varices, ascites, encephalopathy.

Hepatitis

Viral hepatitis A–E inflames the lobules; B and C become chronic, and together cause most liver cancer.

Hepatocellular carcinoma

Arises almost always on diseased ground — cirrhotic livers — and alphafetoprotein plus ultrasound screen for it.

Related conditions

• Gallstones
• Fatty liver disease (MASLD)
• Cirrhosis
• Hepatitis B
• Hepatitis C
• Alcohol-related liver disease
• Liver cancer (hepatocellular carcinoma)
• Hereditary haemochromatosis
• Primary biliary cholangitis
• Malaria