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The adult human liver normally weighs between 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 liver lies anterior to the gallbladder and superior to the right kidney.
The livers supplied by two major blood vessels: the hepatic artery and the portal vein. Te hepatic artery normally comes off the celiac trunk. The portal vein brings venous blood from the digestive tract, produced in the liver is collected in bile capillaries which merge to form bile ducts. These eventually drain into the right and left hpatic duts, which in turn merge to form the commonhepatic duct. Te cystic duct 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 te cystic duct. The common bile duct and the pancreic duct enter the duodenum togeher at the Ampulla of Vater. The branchings of the bile ducts resemble those f a tree, and indeed the term "biliary tree" is commonly used in this setting.It is unique as the only internal human organ capable of natural regeneration of lost tissue; as little as 25% of remaining liver can regenerate into a whole liver again.

Surface anatom
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 srface landmarks. Traditional gross anatomy divided the liver into four lobes based on surface features.he falciform ligament is visible on the front of the liver. This divide the liver into a left anatomical lobe, and a right anatomical lobe.If te liver is flipped over, to look at it from behind there are two additinal lobes between the right and left. These are the caudate lobe and below this the quadrate lobe.From behind, the lobes are divied up by the liamentum venosum and ligamentum teres anything left of these is the left lobe, the transverse fissure divides the caudate from the quadrate lobe, and the right sagittal fossa, which the inferior vena cava runs over, separates these two lobes from the right lobe.

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 artry enter the liver is the hilum or "porta hepatis". The duct, vein, an artery divide into left and right branche, and the portions of the liver supplied by these branches constitute the fnctional left and right lobes. The functinal lobes are separated by a plane joining the gallbladder fossa to te 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

Fetal blood supply
In the growing fetus, a major source of blood to the liver is the ubilical vein which supplies nutrients to the growing fetus. The umbilical vein entrs the abdomen at the umbilicus, and passes upward along the free margin of the falciform ligament of the liver to the inferior surface of the liver. There it joins with the left branch of the portal vein. The ductus venosus carries blood from the left portal vein to the left hepatic vein and thence to the inferior vena cava, allowing pacental blood to bypass the liver.fter birth, the umbilical vein and ductus venosus are completely oliterated two to five days postpartum; the former becomes the ligamentum teres and the latter becomes the ligamntum venosum. In the disease state of cirrhosis and portal hypertension, the umbilical vein can open up again.

Physiology
The various functions of the liver are carried out by the liver cells or hepatocytes.The liver produces and excretes bile required for food digestion. Some of the bile drains directly into the duodenum, and some is stored in the gallbladder.
The liver performs several roles in carbohydrate metabolism:
Gluconeogenesis (the formation of glucose from certain amino acids, lactate or glycerol)Glycogeneis (the formation of glycogen from glucose
The breakdown of insulin and other hormones The liver also performs several roles in lipid metabolism: Cholesterol synthesis The production
The liver produces coagulation factors I as well as protein C, protein S and antithrombin.
The liver breaks down hemoglobin (bile pigments are its metabolites), toxic substances and most medicinal products. This sometimes results in toxication, when the metabolite is more toxic than its precursor.
The liver converts ammonia to urea.
The liver stores a multitude of substances, including glucose in the form of glycogen, vitamin B12, iron, and copper.
In the first trimester fetus, the liver is the main site of red blood cell production. By the 42nd week of gestation, the bone marrow has almost completely taken over that task.
Producing an artificial organ or device capable of emulating all functions of the liver is outside the reach of science in the foreseeable future. Some functions can be emulated by liver dialysis, an experimental treatment for liver failure.

Diseases of the live
Many diseases of the liver are accompanied by jaundice caused by increased levels of bilirubin in the system. The bilirubin results from the breakup of the hemoglobin of dead red blood cells; ormally, the liver removes bilirubin from the blood and excretes it through bile.Hepatitis, inflammation of the liver, caused mainly by various viruses but also by some poisons, autoimmunity or hereditary conditions.
Cirrhosis is the formation of fibrous tissue in the liver, replacing dead liver cells. The death of the liver cells can for example be caused by viral hepatitis, alcoholism or contact wih other liver-toxic chemicals
Hemochromatosis, a hereditary disease causing the accumulation of iron in the body, eventually leading to liver damage
Cancer of the liver primary hepatocellular carcinoma or cholangiocarcinoma and metastatic cancers, usually from other parts of the gastrointestinal tractWilson's disease, a hereditary disease whih causes the body to retain copper
Primary sclerosing cholangitis, an inflammatory disease of the bile duct, autoimmune in nature.
Primary biliary cirrhosis, autoimune disease of small bile ducts
Budd-Chiari syndrome, obstruction of the hepatic vein.
A number of liver function tests are available to test the proper function of the liver. These are enzymes that are most abundant in liver tissue, metabolites or products.

Liver transplantation
Liver transplantation is an option for those with irreversible liver failure. Most transplants are done for chronic liver diseases leading to cirrhosis, such as chronic hepatitis C, alcoholism, autoimmune hepatitis, and many others. Less commonly, liver transplantation is done for fulminant hepatic failure, in which liver failure occurs over days to weeks. Liver allografts for transplant usually come from non-living donors who have died from f brain injury. Living door liver transplantation is a technique in which a portion of a living person's liver is removed and used to replace the entire liver of the recipient. This was first performed in 1989 fchild. More recently, adult-to-adult liver transplantation has been done using the donor's right hepatic lobe which amounts to 60% of the liver. Due to the ability of the liver to regenerate, both the donor and recipient end up with normal liver function if all goes well. This procedure is more controversial as it entails performing a much larger operation on the donor, and indeed there have been at least two donor deaths out of the first several hundred cases.

Analogous organs
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

Liver as food
Mammal and bird livers are commonly eaten as food: products include liver paté, Leberwurst, Braunschweiger, foie gras and chopped liver.Both animal and fish livers are rich in Vitamin A, cod liver oil being commonly used as a supplement. Vitamin A levels can be toxic, particularly in polar animals; the Antarctic explorers Douglas Mawson and Xavier Mertz were both poisoned, the latter fatally, from eating husky liver.

Cultural allusion
In Greek mythology, Prometheus was punished by the gods for revealing fire to humans by being chained to a rock where a vulture (or an eagle, Ethon) would peck out his liver, which would grow again overnight. Curiously, the liver is the only human internal organ that actually can regenerate itself to a certain extent, a characteristic which may have already been known to the Greeks.

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