The liver is an abdominal internal organ odd and asymmetrical, placed at the man in the Hypochondre right and which provides three vital functions: a function of purification, a function of synthesis and a function of storage. They is bulkiest of the human internal organs (2 percent of the body weight, that is to say an average of 1 500 grams) and the body of the human body which carries out the greatest number of chemical conversions. The medical discipline which is attached to him names the Hépatologie.
A video in 3D on the liver and the gall bladder is visible in the medical encyclopedia Vulgaris:
Anatomy
The liver is composed of a left lobe (1/3 of volume) and of a right lobe (2/3) separated by the round ligament. The left liver receives the left branch of division of the hepatic artery and the portal vein, the right liver the right branch. The liver is divided into eight segments, numbered of I with VIII according to the hepatic segmentation of Couinaud which is based on the division of the Portal vein and of the hepatic Artère. This segmentation is essential for the hepatic surgery since it allows the ablation of a segment without obstructing the vascularization of the other segments. It is surrounded of the Capsule of Glisson, composed of péritonéaux layers.
Vascularization
The blood contribution is carried out by the hepatic Artère, bringing oxygenated blood, and by the Portal vein bringing back the blood of the digestive tract rich in nutrients in period post-prandiale. The blood of these two vessels mixes in the hepatic sinusoids which walk on between the spans of hépatocytes to meet in a Veine centrolobulaire. The venous return of the liver is carried out by the hepatic veins, also called know-hepatic veins, which throw in the lower Vena cava.
Bile ducts will intra and extra-hepatic
See also: bile Ducts
The hépatocytes secrete the Bile in the biliary canaliculi which confluent and form the hepatic channels right and left whose meeting forms the common hepatic channel which leaves the liver on the level of the hepatic hile. The Canal cystic resulting from the Gall bladder is thrown in the hepatic channel common which becomes the Cholédoque, which is brought together in the Duodénum.
Structure
The liver consists of hepatic cells (hépatocytes) organized out of spans around the sinusoids the functional unit of the liver is the hepatic lobule. Its exchanges with the remainder of the body are done for the majority through its double blood irrigation (Portal vein and hepatic Artère), which ends in a multitude of capillaries until the interior of the liver.80% of the cells of the liver are hépatocytes, but there exist other cellular types:
- cells of the bile ducts
- cells endothéliales
- cells of Küpfer (macrophage)
- cells of Ito (metabolic function of the vitamin has and the lipids, and manufactures the cellular extra matrix around cells endothéliales)
- lymphocytes hépatocytaires
Functions
Biliary function
- Production of Bile in direction of the Gall bladder and the Duodenum.
Nutritional function
- Role in the Metabolism of the Glucid S:
- decomposition of the Insulin and others Hormone S,
- Néoglucogénèse (formation of Glucose starting from Amino-acid),
- Glycogénolyse (formation of Glucose starting from Glycogen),
- Glycogénogénèse (formation of Glycogen starting from Glucose).
- Role in the metabolism of the Lipid S:
- synthesis of Cholesterol,
- degradation of the Cholesterol in biliary acids. The liver is the only body allowing the elimination of cholesterol
- production of Triglycéride S.
- synthesis of Lipoprotéine S
Blood function
- Role in the metabolism of the Protein S:
- production of the factors of coagulation (I (Fibrinogen) III, V, VII, IX, XI).
- Destruction of the Red blood corpuscle S and aged Leucocyte S, as well as certain bacteria present in blood.
The liver is also the most important regulator of glycemia in blood (and more precisely plasma). Indeed it is the only body to be passed from producer to storage of glucose. It is in period of fast that the liver rejects glucose in blood. Thanks to the enzyme glucose-6-phosphatase, it destroys glycogen, synthesized after storage, in glucose. This enzyme being non-existent in fat fabrics (like the muscles), the synthesized glycogen cannot be destroyed in glucose then salted out in blood.
Antitoxic function
Martial function
- Storage of a multitude of substances, of which the Vitamin B12, the Iron, the Copper and the Glucose (in the form of Glycogen). Those are recovered at the time of the destruction of old red blood corpuscles.
Pathologies
Primitive cancers of the liver
- Carcinome hépatocellulaire
- Carcinome fibrolamellaire: rare, reached rather the woman
- Hépatoblastome: child, hépatocytes fetal
- Angiosarcome: thorotrast, chloride Vinyl, steroids androgens
- Hépatome: Aflatoxine S
Secondary cancers
Hepatic secondary metastases coming from following primitive cancers:- Carcinomes: colonist, bronchi, center, prostate, kidney
- endocrine Cancers, cardia,
- and not to forget secondary metastases following melanomists and more dramatic the melanomists choroïdiens.
Benign hepatic tumors
- Hémangiomes : prevalence (1 - 2%)
- Adenoma: rare, reached the woman, owe with the oral contraceptives
- nodular Hyperplasie focal distance: rare
Others
- hepatic Cirrhosis
- primitive biliary Cirrhosis
- acute alcoholic Hepatitis
- Viral hepatitis
- Hémochromatose
- Disease of hepatic Wilson
- Steatosis
- hepatic Adénomatose
- the Syndrome of Budd-Chiari, due to the obstruction of the hepatic vein.
- the Disease of Gilbert, due to a genetic anomaly of the metabolism of the bilirubine.
Transplantation
See also: hepatic Transplantation
Generally, a damaged liver is regenerated spontaneously. In the contrary case, the liver can be replaced surgically. The liver intended for transplantation can come either from a corpse or of an alive donor. In this last case, the donor sees itself withdrawing part of its liver which is transplanted at the patient. Each half of the liver is regenerated in a complete liver.
Tripe shop (food)
In Tripe shop, the liver is an edible animal meat which belongs to the Abats. It must be consumed in cooked form (to avoid the Toxocarose).
Its content of Protides is from 20 to 22% and its content of Lipides is particularly reduced, of 4% (chicken, ox, sheep, lamb) with 5% (pig, calf), which makes a thin “meat of it”, enough digeste. Its content of cholesterol and purins is high but this aspect is in general to relativize, within the framework of a varied and balanced food. The meat offals and thus the liver, in particular that of Ox, are also charged out of lead than other meats but in a content proportionally less than certain fish (which contain moreover definitely more mercury).
The liver generally cooks stove. The liver of Veau (fair chestnut with the cut) is generally more to tend; it is tasty stove, roasted or jumped. The livers of lamb or heifer (red with the cut), tender, can be also roasted out of skewers. The livers of sheep and ox are hardly goûteux. The liver of pig is especially used in the manufacture of pies and pots.
The liver is a major source of Vitamines and Rock salt essential. The calf's liver is rich in Vitamine has (just like the liver of pig) but also in vitamins B1, B2, B5 or Pantothenic acid, B9 or Folic acid, B12, C, out of iron, zinc, phosphorus and potassium. Goûteux, it is also the most expensive liver.
The livers of ox, sheep and chicken (the least rich in vitamins and iron) practically do not contain a vitamin has; on the other hand they are also rich in thiamin, riboflavin and niacine, Amino-acid which plays a key role in the organization for the energy utilization.
- AMVF - Association of the Patients of the Vessels of the Liver
Simple: Liver Zh-min-nan: Koaⁿ
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