The liver is an abdominal odd and asymmetrical housed man in the right hypochondria, fits under the right phrenic, the upper reaches epigastriquepuis hollow hyponcondre which provides three vital functions: a function of purification, a function of synthesis and storage function. It is the largest human viscera (2 percent body weight, an average of 1 500 grams) and the organ in the body which performs the largest number of chemical transformations. The medical discipline that is attached is called hepatology.
According to the segmentation of liver Couinaud the liver is divided into sectors, themselves divided into segments.
The extra-hepatic veins delineate the liver sectors: Hepatic Vein separates the left side of the industry sector paramedian left, Hepatic Vein median separates the right liver liver left ie the area left paramedian sector earlier right (or right paramedian sector) and Hepatic Vein right between the industry sector right anterior posterior right (or right side sector).
The branches of division of the portal vein delineate areas of the liver into eight segments numbered I to XIII on the underside of the liver in the opposite direction clockwise:
* I segment is the Spiegel lobe and part of the liver in front of the vena cava;
* Segment II is the sector post left;
* The segment III and IV correspond to the left anterior sector
* V segment is the lower part and the segment VIII at the upper right anterior segment;
* Segment VI is the lower and the segment VII at the upper segment of the right post.
Thus, the law contains liver segments V, VI, VII and VIII and the left liver includes segments II, III and IV.
The division anatomical liver divides the liver into 2 lobes separated by the falciform ligament (or suspensory ligament):
* The right lobe (2 / 3 the volume) includes more right liver segment IV
* The left lobe (1 / 3 the volume) consists of the left liver segment IV less, it contains segments II and III.
Surgery on the liver breaks down into 2 hemi-livers: foie right (segment I, II, III, IVA and IVB) and Liver left (segment V, VI, VII, VIII and IX) The liver receives the left arm left division of the hepatic artery and the portal vein, liver right branch right. This segmentation is essential for liver surgery because it allows the removal of a segment without disrupting vasculature other segments. It is surrounded by the capsule Glisson, composed of sheets peritoneal, this vehicle capsule to the painful sensation (the liver is not innervated it can not convey the pain).
The blood supply is produced by the hepatic artery, bringing oxygenated blood, and the portal vein bringing blood from the digestive tract rich in nutrients post-prandial. The blood of these two vessels mixes in liver sinusoids who walk between spans of hepatocytes to meet in a centrilobular vein. The venous return of the liver is by the hepatic veins, also called extra-hepatic veins, which drain into the inferior vena cava.
Bile duct intra-and extra-hepatic
Hepatocytes secrete bile into the bile canaliculus confluence and form channels hepatic right and left the meeting which forms the common liver channel which leaves the liver at the hepatic hilum. The cystic duct from the gall bladder empties into the liver channel which becomes the common bile duct, which s'abouche in the duodenum.
The liver consists of liver cells (hepatocytes) spans organized around functional unit sinusoids The liver is the liver lobule. Its trade with the rest of the body are largely through its dual blood supply (portal vein and hepatic artery), which ends with a multitude of hair up inside the liver.
80% of liver cells are hepatocytes, but there are other cell types:
* Bile duct cells
* Endothelial cells
* Kupfer cells (macrophage)
* Ito cells (metabolic function of vitamin A and lipids, and makes the extra cellular matrix around endothelial cells)
* Lymphocytes hepatocyte
* Role in the metabolism of carbohydrates:
o decomposition of insulin and other hormones,
o gluconeogenesis (formation of glucose from amino acids)
o glycogenolysis (formation of glucose from glycogen)
o glycogenesis (formation of glycogen from glucose).
* Role in the metabolism of lipids:
o synthesis of cholesterol,
No degradation of cholesterol in bile acids. The liver is the only body to remove cholesterol
o production of triglycerides.
o synthesis of lipoproteins
* Role in the metabolism of proteins:
o production of clotting factors (I (fibrinogen) III, V, VII, IX, XI).
* Destruction of red blood cells and aging, and certain bacteria in the blood.
* Transformation of bilirubin free (toxic) in conjugated bilirubin (nontoxic). (Bilirubin comes from the degradation of red blood cells in the spleen).
The liver is the most important regulator of blood glucose in the blood (and specify the plasma). Indeed it is the only body to move from producer to storage of glucose. It said it was hypoglycemic (storage of glucose as glycogen) and qu'hyperglycémiant (release of glucose in the blood after having made a glycogenolysis). It is in times of fasting that the liver releases glucose in the blood. With the enzyme glucose-6-phosphatase, it destroys the glycogen synthesized after storage, into glucose. This enzyme is absent in adipose tissue (like muscles), glycogen synthesized can not be destroyed and released into glucose in the blood. The liver is the only body hyperglycaemic, although lipocytes (fat) and myocites (muscle cells) can store glycogen.
* Destruction of toxins and drugs.
* Conversion of ammonia into urea.
* Storage of a variety of substances, including vitamin B12, iron, copper and glucose (as glycogen). These are recovered at the destruction of old red blood cells.
Primary liver cancer
* Hepatocellular carcinoma
* Fibrolamellaire Carcinoma: rare, is rather Women
* Hepatoblastoma: child, fetal hepatocytes
* Angiosarcoma: thorotrast, Vinyl chloride, androgenic steroids
* Hepatocellular carcinoma: aflatoxins
Liver metastases from cancers primitive following:
* Carcinomas: colon, bronchus, breast, prostate, kidney
* Endocrine cancers, cardiac,
* And do not forget the secondary metastatic melanoma and later to more dramatic choroidal melanoma.
Benign liver tumors
* Hemangioma: prevalence (1 - 2%)
* Adenoma: rare, reaches women, due to oral contraceptives
* Focal nodular hyperplasia: rare
In tripe, liver meat is edible animal which is part of offal. It must be consumed cooked form (to avoid toxocariasis).
Its protein content is 20 to 22% and its fat is reduced by 4% (chicken, beef, mutton, lamb) 5% (pork, veal), making it a "meat" lean, enough light. His cholesterol content and is high in purines but this is usually relative, as part of a varied and balanced diet. Offal and therefore the liver, especially beef, are also responsible for lead as other meat content but in a proportionally lower than some fish (which also contain significantly more mercury).
The liver is usually cooked fried. The calf liver (blond to brown the cut) is usually the most tender and is delicious fried, grilled or sautéed. Livers lamb or calf (red cup), tender, can also grill skewers. The livers of sheep and beef are not very tasty. The pig liver is mainly used in the manufacture of pies and terrines.
The liver is a major source of vitamins and minerals essential. The calf liver is rich in vitamin A (like pig liver) but also vitamins B1, B2, B5 or pantothenic acid, B9 or folic acid, B12, C, iron, zinc, phosphorus and potassium. Tasty, the liver is also the most expensive.
The livers of beef, mutton and chicken (the less rich in vitamins and iron) contained almost no vitamin A; however they are also rich in thiamine, riboflavin and niacin, amino acids play a crucial role in body for energy use.
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