The liver is the largest solid organ in the body, and is also the largest gland. It weighs about three and a half pounds (1.6 kilograms). It measures about 8 inches (20 cm) horizontally (across) and 6.5 inches (17 cm) vertically (down) and is 4.5 inches (12 cm) thick.

Its normal function is essential to good health. The liver plays a major role in maintaining normal blood sugar levels, an important source of energy for the brain, heart and muscles. The liver is also responsible for manufacturing a number of proteins which comprise the building blocks of cells and tissues throughout the body. For example, serum albumin, one of the proteins produced in the liver, is the most abundant protein in the blood circulation and helps to maintain normal blood volume for the heart and vascular system. See what the liver does and how it can do so much.

The liver also maintains several biochemical pathways that permit the detoxification, or breakdown, of toxic products that accumulate because of the body’s normal chemical functions and exposure to environmental poisons. For example, protein metabolism in the liver and other body tissues results in the production of ammonia, which is normally converted in the liver to a harmless metabolite called urea for excretion in the urine. Environmental toxins that enter the body through the lungs or digestive tract pass to the liver and are broken down through specific chemical pathways to permit excretion in the bile or urine.

Another important function of the liver is to manufacture bile, which plays a role in the digestion and absorption of many constituents in the normal diet. Bile, which is produced in the liver, is stored in the gall bladder, a specialized storage organ located just below the liver. The gall bladder empties bile into the intestine when food is ingested.

Diseases of the liver are the third most common cause of death in Americans during their most productive years and the seventh most frequent disease-related cause of death in the United States overall. Liver disease accounts for up to $8 billion yearly in economic losses. Approximately 500,000 cholecystectomies are performed each year due to gall stone disease, caused mainly by increased cholesterol secretion into bile. Alcoholic liver disease is the most common cause of liver injury in the United States. Hepatitis B and C infect approximately 5 million persons. Hepatocellular carcinoma, or liver cancer may be a consequence of these disorders and is a major interest of our physicians.

With the onset of liver disease, the cells of the liver, called hepatocytes are injured or die. If the injury is mild and reversible, the cells may regenerate and the patient may be left with an entirely normal liver. This remarkable capacity of the liver to regenerate is a unique feature of the organ. When the injury is more severe or sustained, regeneration may be incomplete or healing may occur with the development of fibrosis or scars, which can cause cirrhosis.

Physicians ordinarily make a diagnosis of cirrhosis using some form of liver biopsy, permitting the identification of marked distortion of the normal architecture of the liver by scar formation and irregular incomplete areas of regeneration. The development of cirrhosis leads to the obstruction of normal blood flow through the liver, resulting in increased pressure in the veins throughout the abdomen. A consequence for patients is the development of enlarged blood vessels or varices, in the lower end of the esophagus that can bleed and result in abnormal function of other organs and even death. When cirrhosis develops, the normal functions of the liver are disrupted, leading to raised ammonia levels that can interfere with the normal function of the brain, producing coma. Decreased albumin levels may contribute to fluid accumulation.

Some Hepatology Terms

ALBUMIN
Main circulating protein in bloodstream synthesized by liver. Measured in blood by laboratory to assess function of liver.

ALCOHOLIC HEPATITIS
Hepatitis with unique pathologic liver injury varying widely in severity and caused by chronic, heavy alcohol ingestion.

ALKALINE PHOSPHATASE
Enzyme or protein synthesized by the liver in large amounts when there is obstruction of the bile ducts to the normal flow of bile. Measured in blood by laboratory to assess function of liver.

ALT (Alanine Aminotransferase)
Enzyme or protein that leaks from the damaged liver. Measured in blood to assess liver injury.

AMA (Antimitochondrial Antibodies)
The mitochondria create energy for the cells in your body to use. They’re critical to the normal functioning of all cells. They are an example of an autoimmune response that occurs when the body turns against its own cells, tissues, and organs. When this happens, the immune system attacks the body as though it were an infection.

ANTI-NUCLEAR ANTIBODY TEST
Laboratory test, when positive suggests the presence of some form of autoimmune illness.

ASCITES
Fluid accumulation around the liver and other abdominal organs resulting from portal hypertension.

AST (Aspertate Aminotransferase)
Enzyme or protein that leaks from the damaged liver. Measured in blood to assess liver injury.

AZATHIOPRINE
Drug marketed with trade name Imuran. Used to treat a number of diseases of unknown or autoimmune cause. Also used to treat organ transplant recipients to help prevent graft rejection.

BILE DUCT
Large tube-like structure that delivers bile from the liver to the intestine to help digest food.

BILE DUCTULE
Microscopic bile duct that collects bile from liver cells and delivers it to the large bile duct outside the liver.

BILE
Fluid produced by liver cells and carried by bile ductules into the bile duct and stored in gall bladder between meals. Contains substances needed to aid in the digestion of food. Provides a method for the body to eliminate toxic substances that are broken down by the liver.

BILIRUBIN
Chemical breakdown product of hemoglobin. Measured in blood specimen by laboratory to assess function of liver.

CERULOPLASMIN
Serum protein measured by laboratory to help in the diagnosis of Wilson’s Disease.

CHOLANGIOCARCINOMA
Malignant tumor that arises from bile ducts or ductules.

CHRONIC HEPATITIS
Prolonged inflammation and death of liver cells persisting for six months or more caused by hepatitis viruses, autoimmune factors, and on occasion, unknown conditions.

CIRRHOSIS
Used as a pathologic term to denote extensive scarring in the liver along with irregular nodules of regenerating liver tissue. Used as a clinical liver term to refer to the condition of individuals with liver disease accompanied by ascites, esophageal variceal bleeding, or hepatic encephalopathy.

COMPUTERIZED TOMOGRAPHY (CT) SCAN
A specialized x-ray procedure utilizing multiple radiographic films of the liver to construct with computer technology, a 2-dimensional picture of the liver.

CYCLOSPORINE A
Drug marketed with trade names Sandimmune and Neoral. Given to organ transplant recipients to prevent the body from rejecting the graft. Inhibits immune system from rejecting foreign tissue.

DRUG HEPATITIS
Hepatitis caused by a drug. Causative drugs include isoniazid (INH), Alpha Methyldopa, and Dilatin.

ENDOSCOPE
A flexible instrument containing fiberoptic bundles and a light source used by physicians to examine the esophagus, stomach, and duodenum.

ESOPHAGEAL VARICES
Dilated vessels in the lower end of the esophagus that result from portal hypertension. Often results in gastrointestinal bleeding, a life threatening complication of cirrhosis.

FERRITIN
Iron-containing serum protein measured by laboratory to help establish a diagnosis of hemochromatosis.

GALLBLADDER
Specialized organ that joins the bile duct and is located just under the liver. Stores bile secreted by the liver between meals and empties this fluid into the intestine to help with digestion at the time of food intake.

GGTP (Gamma Glutamyl Transpeptidase)
Enzyme or protein synthesized by the liver in large amounts when there is obstruction of the bile ducts to the normal flow of bile. Measured in blood by laboratory to assess function of liver.

HEMANGIOSARCOMA
Malignant tumor that arises from the blood vessels of the liver.

HEMOCHROMATOSIS
A genetic disorder involving increased absorption of iron by the gastrointestinal tract and deposition in the liver resulting ultimately in cirrhosis and liver failure.

HEPATIC ARTERY
Main artery that supplies fully oxygenated blood to the liver. Comes from aorta to underside of the liver.

HEPATIC VEIN
Main outflow vein of liver connecting liver to vena cava and then to heart. Located on topside of liver.

HEPATITIS A ANTIBODY (Anti HA)
Main laboratory test used to detect hepatitis A. Detects antibody produced by patient’s immune system in response to hepatitis A virus.

HEPATITIS A
Hepatitis caused by hepatitis A virus. Most common in children and adolescents. Usually resolves in a few weeks. Almost never fatal. Transmitted by contaminated food and water.

HEPATITIS B CORE ANTIBODY (Anti-HBc)
Laboratory test that detects antibody produced by patient’s immune system in response to internal components of the hepatitis B virus.

HEPATITIS B SURFACE ANTIBODY (Anti-HBs)
Laboratory test that detects antibody produced by patient’s immune system in response to surface component of the hepatitis B virus.

HEPATITIS B SURFACE ANTIGEN (HBsAg)
Main laboratory test used to establish a diagnosis of hepatitis B. Detects component of hepatitis B virus circulating in patient’s serum.

HEPATITIS B VIRUS DNA (HBV DNA)
Laboratory test that detects internal component of hepatitis B virus.Reflects degree of activity or rate of multiplication of the virus.

HEPATITIS Be ANTIGEN (HBeAg)
Laboratory test that helps to determine degree of activity, or rate of multiplication, of hepatitis B virus.

HEPATITIS B
Hepatitis caused by the hepatitis B virus, transmitted by infected serum. Full recovery in more than 90{8a67dea16ade4df0bdc75a32af750148bf01dab229db39fe87e8dd3665ac86f1} of infected individuals in a few days to a few weeks. Five to ten percent of individuals may develop chronic hepatitis, cirrhosis, or severe liver failure requiring transplantation.

HEPATITIS C ANTIBODY (Anti-HC)
Laboratory test that detects antibodies produced by patient’s immune system in response to presence of the hepatitis C virus. Laboratory test methods include enzyme immunoassay (EIA) and radioimmunoblot assay (RIBA).

HEPATITIS C RNA (HC RNA)
Laboratory test that measures the levels of components of the hepatitis C virus in the patient’s serum.

HEPATITIS C
Hepatitis caused by the hepatitis C virus. Transmitted by infected serum. Less than half the patients recover with disappearance of the virus. Individuals may develop chronic hepatitis, cirrhosis and severe liver failure, usually after many years of infection.

HEPATITIS D ANTIBODY (Anti-HD)
Laboratory test that detects antibodies in serum produced by patient’s immune system in response to the presence of hepatitis D virus.

HEPATITIS D
A unique viral particle that infects individuals only when there is concommitent hepatitis B infection. Increases the likelihood of severe liver damage and cirrhosis.

HEPATITIS E
– Hepatitis caused by the hepatitis E virus. Transmitted by infected food and water and more common in tropical and subtropical regions of the world than in the United States. Substantial fatality in pregnant women.

HEPATITIS
Liver disorder characterized by inflammation and random necrosis (death) of liver cells. Caused by viruses, drugs, alcohol, toxins and other injurious agents.

HEPATOCELLULAR CARCINOMA (Hepatoma)
Most common malignant tumor of the liver. Arises from the main cells of the liver.

INFLAMMATORY BOWEL DISEASE
Comprises inflammatory diseases of the large and small intestine that are chronic in nature and are often associated with the development of sclerosing cholangitis.

INTERFERON
Drug produced by several companies with brand names: Intron, Roferon, and Infragen for the treatment of hepatitis B and C. Interferons are natural substances produced by the body that help to strengthen the immune system and display anti-viral activity against infections such as hepatitis C.

LIVER BIOPSY
Procedure used to take a sample of the liver to study under a microscope to determine the degree of liver damage or the type of liver injury. Can be performed by passing a needle between the ribs on the right side or at the time of surgical procedure where the abdomen is opened.

LIVER FAILURE
A term used to refer to the clinical picture produced by end-stage cirrhosis manifested by esophageal variceal hemorrhage, ascites, and/or hepatic encephalopathy.

MITOCHONDRIAL ANTIBODY
Laboratory test used to help establish a diagnosis of primary biliary cholangitis, originally known as primary biliary cirrhosis.

MYCOPHENOLATE MOFETIL
Drug marketed with trade name Cellcept. Given to organ transplant recipients to prevent the body from rejecting the graft. Inhibits immune system from rejecting foreign tissue.

PORTAL HYPERTENSION
Increased pressure in the portal vein and blood vessels from the intestine resulting from scarring (cirrhosis) of the liver, often contributing to ascites, hepatic encephalopathy, and esophageal variceal bleeding.

PORTAL VEIN
Main vein that brings blood from the intestine and stomach into the liver for processing foods. Located on the underside of the liver.

PORTAL-SYSTEMIC ENCEPHALOPATHY
Refers to a condition of mental status changes, ranging from mild confusion to a coma-state resulting from increased ammonia transferred to the brain because of the inability of the liver to remove this toxic compound from the circulation.

PREDNISONE
Drug used to treat a number of autoimmune diseases. Broken down by body into a product normally produced by the adrenal gland. Has broad immunosuppressive effects and is often used for management of organ transplant recipients.

PRIMARY BILIARY CHOLANGITIS (Originally known as Primary Biliary Cirrhosis)
Chronic liver disease, most common in women, caused by inflammation of bile ductules leading to a raised serum alkaline phosphatase and serum bilirubin. Course may be prolonged over many years or may proceed to liver failure in 3-5 years.

PRIMARY SCLEROSING CHOLANGITIS
A liver disorder that most commonly occurs in patients with inflammatory bowel disease resulting in destruction of the bile ductules in the liver leading to a marked increase in the serum alkaline phosphatase and serum bilirubin. Ultimately leads to cirrhosis and liver failure.

PROTHROMBIN TIME
Test performed by laboratory that measures time required for a blood sample to clot. Reflects overall function of the liver.

RIBAVIRIN
One of a new class of drugs used to treat viral infections called nucleocide analogues. These drugs interfere in a specific way with the mechanisms used by viruses for multiplication.

TACROLIMUS (FK506)
Drug marketed with trade name Prograf. Given to organ transplant recipients to prevent the body from rejecting the graft. Inhibits immune system from rejecting foreign tissue.

TOXIC HEPATITIS
Hepatitis caused by an industrial chemical such as carbon tetrachloride or phosphorus.

ULTRASOUND EXAMINATION
A test that utilizes ultrasound waves to bounce off internal organs of the body to construct a picture used by physicians as a non-invasive study of the liver.

VIRAL HEPATITIS
Hepatitis caused by any of several known viruses for which physicians can perform tests.

WILSON’S DISEASE
A genetic disorder leading to increased retention of copper in the liver resulting in chronic hepatitis and cirrhosis. If untreated, liver failure may occur.