liver(redirected from Human liver)
Also found in: Dictionary, Thesaurus, Encyclopedia.
As the chief supplier of glucose in the body, the liver is sometimes called on to convert other substances into sugar. The liver cells can make glucose out of protein and fat. This may also work in reverse: the liver cells can convert excess sugar into fat and send it for storage to other parts of the body.
In addition to these functions, the liver builds many essential proteins and stores up certain necessary vitamins until they are needed by other organs in the body.
The liver also helps to maintain the balance of sex hormones in the body. A certain amount of female hormone is normally produced in males, and male hormone in females. When the level of this opposite sex hormone rises above a certain point, the liver takes up the excess and disposes of it.
Finally, the liver polices the proteins that have passed through the digestive system. Some of the amino acids derived from protein metabolism cannot be used by the body; the liver rejects and neutralizes these acids and sends them to the kidneys for disposal.
There are many enzymes that occur in the liver and are released into the blood when there is liver damage or biliary obstruction. The ones most commonly determined in the laboratory are alkaline phosphatase, aspartate transaminase (AST), and alanine transaminase (ALT). AST and ALT are also commonly called (serum) glutamic-oxaloacetic transaminase (GOT or SGOT) and (serum) glutamic-pyruvic transaminase (GPT or SGPT). Alkaline phosphatase is elevated in patients with intrahepatic or extrahepatic obstruction of bile flow, as in cholestatic jaundice or in primary or metastatic carcinoma. AST and ALT are elevated in patients with hepatocellular injury as in acute viral or toxic hepatitis.
Both ultrasonography and radioisotope scans (scintiscans) are useful in demonstrating space-occupying lesions of the liver, such as cysts, abscesses, and tumors. Ultrasonography is an excellent tool for evaluating ascites or preparing for a liver biopsy. The scintiscans use technetium-99m sulfur colloid, which is taken up by the reticuloendothelial cells of the liver and spleen, or gallium-67, which has an affinity for abscesses and certain tumors. On a colloid scan, abscesses and tumors appear as filling defects or “cold spots”; on the gallium scan, they appear as “hot spots.”
A needle biopsy of the liver is useful in demonstrating the presence of cirrhosis, steatosis, alcoholic hepatitis, chronic hepatitis, and carcinoma. Liver biopsy is contraindicated in patients who have clotting defects, severe anemia, or a bacterial infection in an area to be traversed by the biopsy needle, for example, right lower lobar pneumonia.
liv·er(liv'ĕr), [TA] Do not confuse this word with livor.
occult primary malignancyOccult cancer, unknown primary A malignancy of unknown 1º site or origin that is symptomless, which first manifests itself as metastases or secondary–paraneoplastic phenomena, and usually has a poor prognosis; OPMs are problematic as appropriate therapy requires that the primary malignancy be eradicated, and many remain obscure despite aggressive diagnostic work-up; certain malignancies metastasize to certain sites with greater than expected frequency; in OPMs affecting the brain, the primary arises in the lungs in up to 85% Treatment Up to 30% of Pts with metastases from an occult primary adenoCA may respond to chemotherapy–mitomycin C, adriamycin, vincristine; poor response is more common in ♂ and in Pts with liver and/or infradiaphragmatic metastases
Synonym(s): hepar [TA] .
The liver has four lobes, five ligaments, and five fissures and is covered by a tough fibrous membrane, Glisson's capsule, which is thickest at the transverse fissure. At this point the capsule carries the blood vessels and hepatic duct, which enter the organ at the hilus. Strands of connective tissue originating from the capsule enter the liver parenchyma and form the supporting network of the organ and separate the functional units of the liver, the hepatic lobules.
The many intrahepatic bile ducts converge and anastomose, finally forming the secretory duct of the liver, the hepatic duct, which joins the cystic duct from the gallbladder to form the common bile duct or the ductus choledochus, which enters the duodenum at the papilla of Vater. A ring of smooth muscle at the terminal portion of the choledochus, the sphincter of Oddi, permits the passage of bile into the duodenum by relaxing. The bile leaving the liver enters the gallbladder, where it undergoes concentration principally through loss of water absorbed by the gallbladder mucosa. When bile is needed in the small intestine for digestive purposes, the gallbladder contracts and the sphincter relaxes, thus permitting escape of the viscid gallbladder bile. Ordinarily, the sphincter of Oddi is contracted, shutting off the duodenal entrance and forcing the bile to enter the gallbladder after leaving the liver.
The functional units of the liver are the liver lobules, six-sided aggregations of hepatocytes permeated by capillaries called sinusoids. Lining these sinusoids are Kupffer cells, the macrophages of the liver.
The blood supply consists of oxygenated blood from the hepatic artery, a branch of the celiac artery, and blood from all the digestive organs and spleen by way of the portal vein. The end products of digestion and other materials thus pass through the liver before entering general circulation.
The nerve supply consists of parasympathetic fibers from the vagi and sympathetic fibers from the celiac plexus via the hepatic nerve.
The liver is one of the most metabolically active organs of the body. Amino acid metabolism: It synthesizes nonessential amino acids, deaminates excess amino acids for use in energy production, and forms urea, which the kidneys excrete. Bile production: It is responsible for the production of bile salts, which emulsify fats in the small intestine; 800 to 1000 ml of bile is secreted in 24 hr, and the secretion rate is increased greatly during digestion of meals rich in fats. Carbohydrate metabolism: It converts monosaccharides other than glucose to glucose, and stores excess glucose as the starch glycogen, until such energy is needed. Detoxification: It produces enzymes to metabolize potentially harmful substances found in the portal circulation (e.g., alcohol, ammonia, indole, many medications, and skatole) into less toxic ones. Endocrine functions: It facilitates the conversion of levothyroxine to the more metabolically active thyroid hormone, triiodothyronine. Excretion: It discharges the breakdown products of hemoglobin (bilirubin and biliverdin) into the bile; these are eliminated in feces. Fat metabolism: It synthesizes cholesterol as well as lipoproteins for the transport of fat to other body tissues; it converts fatty acids to acetyl groups or ketones, so they may be used as energy sources. Phagocytosis: Its macrophages (Kupffer cells) scavenge bacteria, other pathogens, and senescent red blood cells from the portal circulation. Protein synthesis: It manufactures albumin, alpha-globulins and beta-globulins, complement components, and clotting factors, some of which are dependent on vitamin K. Storage: It stores copper, iron, vitamin B12, and the fat-soluble vitamins A, D, E, and K.
The liver is examined by inspection, auscultation, percussion, and palpation. Inspection of the organ includes indirect assessments (e.g., for jaundice [skin color], palmar erythema, and spider telangiectasias and other signs of chronic liver disease. Auscultation of the liver may reveal bruits associated with liver cancer; auscultation also is used to make a crude estimate of organ size. Percussion of the liver, which is performed in the right midclavicular line, provides another method for roughly estimating size. Palpation of the organ may reveal tenderness, irregular edges, masses, or tumors.
The liver is enlarged, smooth, firm, and painless. Infiltration of other organs may cause kidney failure, intercerebral bleeding, heart failure, anemia, and other diseases and conditions.
The prognosis is unfavorable.
biliary cirrhotic liver
lardaceous liverAmyloid liver.
wandering liverFloating liver.
liverThe largest organ of the ABDOMEN occupying the upper right corner and extending across the midline to the left side. It is wedge-shaped, with the thin edge pointing to the left, of a spongy consistency, reddish-brown in colour and moulded to fit under the domed DIAPHRAGM so that most of it lies behind the ribs. The liver receives chemical substances in the blood, especially in the nutrient-rich blood from the intestines (glucose, amino acids, fats, minerals and vitamins) and processes these according to the needs of the body. It takes up the products of old red blood cells and converts these into a pigment, bilirubin, which together with other substances, form the bile. It breaks down toxic substances into safer forms. Ammonia produced from protein breakdown is converted into urea, which is excreted in the urine. Alcohol and other drugs are altered to safer forms. To a remarkable degree, the liver is able to regenerate itself after disease, toxic damage or injury. But if this capacity is exceeded, functional liver cells form nodules and are replaced by inert fibrous tissue (CIRRHOSIS) and the whole function of the body is severely affected.
liverthe largest and most complex organ of the vertebrate body, with a wide range of functions (see below).several of which are vital for life to continue. In mammals the liver receives a double blood supply, about 70% coming from the HEPATIC PORTAL SYSTEM and 30% from the arterial system. The liver performs the following functions:
- removes excess glucose from the blood and stores it as GLYCOGEN.
- converts glycogen back to glucose when blood sugar levels are low.
- converts food substances to other types, e.g. carbohydrates into fats, amino acids into carbohydrates or fats.
- deaminates amino acids, converting the ammonia produced into urea via the ORNITHINE CYCLE, releasing the nitrogenous wastes into the blood.
- transaminates amino acids (see TRANSAMINATION from one type to another via keto acids.
- detoxifies many harmful compounds.
- manufacturers fats, including cholesterol. (h) manufacturers many plasma proteins, including FIBRINOGEN and PROTHROMBIN.
- stores several important substances, e.g. iron and fat-soluble vitamins.
- excretes bile pigments.
- manufacturers bile salts.
- destroys worn-out red blood cells.
Patient discussion about liver
Q. Why do I have Fatty Liver? I have just had a complete overhaul regarding my health and thankfully the only thing that came back was that I had fatty liver, now I don`t drink, never have, I`m not desperately overweight although have lost 4 stone over a period of time, and I like to think that I eat sensibly, salads, fruit, veg.. Any thoughts anyone?
For the entire article you can go to:
Hope this helps.
Q. What are the risks of cirrhosis of liver? My dad has cirrhosis and I would like to know what are the risks and how does it get treated.
Q. What is Liver Cirrhosis? I read that alcohol can lead to liver cirrhosis. What does cirrhosis mean?