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The liver is an organ in vertebrates including humans. It plays a major role in metabolism and has a number of functions in the body including detoxification, glycogen storage and plasma protein synthesis. It also produces bile which is important for digestion. Medical terms related to the liver often start in hepato- or hepatic from the Greek word hepar for "liver".

Table of contents
1 Anatomy of the liver
2 Functions of the liver
3 Disorders of the liver
4 Liver transplantation
5 Liver-like organs in other animals
6 External links

Anatomy of the liver

Human liver, view from above
View from below
The adult human liver normally weighs between 1.0 - 2.5
kilograms, and is a soft, reddish-brown "wedge-shaped" organ. It is the largest organ in the abdomen and sits immediately under the diaphragm on the right side of the upper abdomen. The gallbladder lies beneath the liver. The right kidney lies below the liver.

The liver is supplied by two major blood vessels: the hepatic artery and the portal vein. The hepatic artery normally comes off the celiac trunk. The portal vein brings venous blood from the digestive tract, so that the liver can process the nutrients and toxins extracted from food. The hepatic veins drain directly into the inferior vena cava.

The bile produced in the liver is collected in bile capillaries which merge to form bile ducts. These eventually drain into the right and left hepatic ducts, which in turn merge to form the common hepatic duct. The cystic duct (from the gallbladder) joins with the common hepatic duct to form the common bile duct. Bile can either drain directly into the duodenum via the common bile duct or be temporarily stored in the gallbladder via the cystic duct. The common bile duct and the pancreatic duct enter the duodenum together at the Ampulla of Vater. The branchings of the bile ducts resemble those of a tree, and indeed the term "biliary tree" is commonly used in this setting.

It is unique as the only human organ capable of natural regeneration of lost tissue.

Surface anatomy

Apart from a patch where it connects to the diaphragm, the liver is covered entirely by visceral peritoneum, a thin, double-layered membrane that reduces friction against other organs. The peritoneum folds back on itself to form the falciform ligament and the right and left triangular ligaments. These "ligaments" are in no way related to the true anatomic ligaments in joints, and have essentially no functional importance, but they are easily recognizable surface landmarks. Traditional gross anatomy divided the liver into four lobes based on surface features.




Functional anatomy

For purposes such as advanced liver surgery, it is crucial to understand the organization of liver based on blood supply and biliary drainage. The central area where the common bile duct, portal vein, and hepatic artery enter the liver is the hilum or "porta hepatis". The duct, vein, and artery divide into left and right branches, and the portions of the liver supplied by these branches constitute the functional left and right lobes. The functional lobes are separated by a plane joining they gallbladder fossa to the inferior vena cava. In the widely used Couinaud or "French" system, the functional lobes are further divided into a total of eight segments based on secondary and tertiary branching of the blood supply. The segments corresponding to the surface anatomical lobes are as follows:

Lobe Couinaud segments
Caudate 1
Left 2, 3
Quadrate 4
Right 5, 6, 7, 8

Fetal blood supply of the liver



Functions of the liver


Disorders of the liver

Many diseases of the liver are accompanied by


Liver transplantation


Liver-like organs in other animals

Arthropods have a digestive gland that functions like a combination of the liver and the pancreas. In insects this organ is known as the fat body.

External links

Digestive system
Mouth - Pharynx - Esophagus - Stomach - Pancreas - Gallbladder - Liver - Duodenum - Jejunum - Ileum - Colon - Cecum - Rectum - Anus