Liver

What Is Liver Function?

• The liver is the largest solid organ in the body, weighing on average about 3.5 pounds.
• The liver carries out a large number of critical functions, including manufacture of essential proteins, and metabolism of fats and carbohydrates.
• The liver carries out a large number of critical functions, including manufacture of essential proteins, and metabolism of fats and carbohydrates.
• The liver also serves to eliminate harmful biochemical waste products and detoxify alcohol, certain drugs, and environmental toxins.
• The liver forms and secretes bile that contains bile acids to aid in the digestion and intestinal absorption of fats and the fat-soluble vitamins A, D, E, and K.
• Diseases that may affect the liver include hepatitis (inflammation of the liver), cirrhosis (scarring), fatty liver, and liver cancer (hepatocellular carcinoma).
Symptoms of liver disease may include:
• bleeding or easy bruising,
• swelling,
• fatigue, and
• jaundice (yellow coloring to the skin and whites of the eyes)

Liver Overview

The liver is the largest solid organ in the body. People may not know that the liver is also the largest gland in the body. The liver is actually two different types of gland. It is a secretory gland because it has a specialized structure that is designed to allow it to make and secrete bile into the bile ducts. It also is an endocrine gland since it makes and secretes chemicals directly into the blood that have effects on other organs in the body. Bile is a fluid that both aids in digestion and absorption of fats as well as carries waste products into the intestine.

What Is the Size of the Liver?

The liver weighs about three and a half pounds (1.6 kilograms). It measures on average, about 8 inches (20 cm) horizontally (across), and 6.5 inches (17 cm) vertically (down), and is 4.5 inches (12 cm) thick.

Liver Location and Anatomy
The liver is located just below the diaphragm (the muscular membrane separating the chest from the abdomen), primarily in the upper right part of the abdomen, mostly under the ribs. However, it also extends across the middle of the upper abdomen and part way into the left upper abdomen. An irregularly shaped, dome-like solid structure, the liver consists of two main parts (a larger right lobe and a smaller left lobe) and two minor lobes. As you can see in the diagram below, the upper border of the right lobe is at the level of the top of the 5th rib (a little less than 1/2 inch below the nipple), and the upper border of the left lobe is just below the 5th rib (about 3/4 inch below the nipple). During inspiration (breathing in), the liver is pushed down by the diaphragm and the lower edge of the liver descends below the margin of the lowest rib (costal margin).

Picture of the liver and where it is located in the abdomen

Liver Location and Anatomy

The liver is located just below the diaphragm (the muscular membrane separating the chest from the abdomen), primarily in the upper right part of the abdomen, mostly under the ribs. However, it also extends across the middle of the upper abdomen and part way into the left upper abdomen. An irregularly shaped, dome-like solid structure, the liver consists of two main parts (a larger right lobe and a smaller left lobe) and two minor lobes. As you can see in the diagram below, the upper border of the right lobe is at the level of the top of the 5th rib (a little less than 1/2 inch below the nipple), and the upper border of the left lobe is just below the 5th rib (about 3/4 inch below the nipple). During inspiration (breathing in), the liver is pushed down by the diaphragm and the lower edge of the liver descends below the margin of the lowest rib (costal margin).

What Are Liver Functions?

The liver has a multitude of important and complex functions. Some of these functions are to:

• Manufacture (synthesize) proteins, including albumin (to help maintain the volume of blood) and blood clotting factors
• Synthesize, store, and process (metabolize) fats, including fatty acids (used for energy) and cholesterol
• Metabolize and store carbohydrates, which are used as the source for the sugar (glucose) in blood that red blood cells and the brain use
• Form and secrete bile that contains bile acids to aid in the intestinal absorption of fats and the fat-soluble vitamins A, D, E, and K.
• Eliminate, by metabolizing and/or secreting, the potentially harmful biochemical products produced by the body, such as bilirubin from the breakdown of old red blood cells, and ammonia from the breakdown of proteins
• Detoxify, by metabolizing and/or secreting, drugs, alcohol, and environmental toxins

Fatty Liver Disease

Fatty liver can be classified as alcohol and nonalcohol related. Alcohol is a direct toxin to the liver and can cause inflammation. Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic related steatohepatitis (NASH) are markedly different illnesses and there are many potential causes that are linked to fat accumulation in the liver.

Some of the causes of fatty liver include:

• Diet: Consumption of excess calories in the diet (the excess caloric intake overwhelms the livers ability to metabolize fat in a normal fashion, which results in fat accumulation in the liver).
• Diseases: Fatty liver is also associated with type II diabetes, obesity, and high triglyceride levels in the blood, celiac disease, and Wilson's disease (abnormality of copper metabolism).
• Medical conditions: Rapid weight loss and malnutrition.
• Medications: Medications such as tamoxifen (Soltamox), amiodarone injection (Nestorone), amiodarone oral (Cordarone, Pacerone), and methotrexate (Rheumatrex Dose Pack, Trexall) are associated with NAFLD.

Liver Conditions

• Hepatitis: Inflammation of the liver, usually caused by viruses like hepatitis A, B, and C. Hepatitis can have non-infectious causes too, including heavy drinking, drugs, allergic reactions, or obesity.
• Cirrhosis: Long-term damage to the liver from any cause can lead to permanent scarring, called cirrhosis. The liver then becomes unable to function well.
• Liver cancer: The most common type of liver cancer, hepatocellular carcinoma, almost always occurs after cirrhosis is present.
• Liver failure: Liver failure has many causes including infection, genetic diseases, and excessive alcohol.
• Ascites: As cirrhosis results, the liver leaks fluid (ascites) into the belly, which becomes distended and heavy.
• Gallstones: If a gallstone becomes stuck in the bile duct draining the liver, hepatitis and bile duct infection (cholangitis) can result.
• Hemochromatosis: Hemochromatosis allows iron to deposit in the liver, damaging it. The iron also deposits throughout the body, causing multiple other health problems.
• Primary sclerosing cholangitis: A rare disease with unknown causes, primary sclerosing cholangitis causes inflammation and scarring in the bile ducts in the liver.
• Primary biliary cirrhosis: In this rare disorder, an unclear process slowly destroys the bile ducts in the liver. Permanent liver scarring (cirrhosis) eventually develops.

Liver Tests Blood Tests:

• Liver function panel: A liver function panel checks how well the liver is working and consists of many different blood tests.
• ALT (Alanine Aminotransferase): An elevated ALT helps identify liver disease or damage from any number of causes, including hepatitis.
• AST (Aspartate Aminotransferase): Along with an elevated ALT, the AST checks for liver damage.
• Alkaline phosphatase: Alkaline phosphatase is present in bile-secreting cells in the liver; it's also in bones. High levels often mean bile flow out of the liver is blocked.
• Bilirubin: High bilirubin levels suggest a problem with the liver.
• Albumin: As part of total protein levels, albumin helps determine how well the liver is working.
• Ammonia: Ammonia levels in the blood rise when the liver is not functioning properly.
• Hepatitis A tests: If hepatitis A is suspected, the doctor will test liver function as well as antibodies to detect the hepatitis A virus.
• Hepatitis B tests: Your doctor can test antibody levels to determine if you have been infected with the hepatitis B virus.
• Hepatitis C tests: In addition to checking liver function, blood tests can determine if you have been infected with the hepatitis C virus.
• Prothrombin Time (PT): A prothrombin time, or PT, is commonly done to see if someone is taking the correct dose of the blood thinner warfarin (Coumadin). It also checks for blood clotting problems.
• Partial Thromboplastin Time (PTT): A PTT is done to check for blood clotting problems.
• Ultrasound: An abdominal ultrasound can test for many liver conditions, including cancer, cirrhosis, or problems from gallstones.
• CT scan (computed tomography): A CT scan of the abdomen gives detailed pictures of the liver and other abdominal organs.
• Liver biopsy: A liver biopsy is most commonly done after another test, such as a blood test or ultrasound, indicates a possible liver problem.
• Liver and spleen scan: This nuclear scan uses radioactive material to help diagnose a number of conditions, including abscesses, tumors, and other liver function problems.

Liver Treatments

• Hepatitis A treatment: Hepatitis A usually goes away with time.
• Hepatitis B treatment: Chronic hepatitis B often requires treatment with antiviral medication.
• Hepatitis C treatment: Treatment for hepatitis C depends on several factors.
• Liver transplant: A liver transplant is needed when the liver no longer functions adequately, whatever the cause.
• Liver cancer treatment: While liver cancer is usually difficult to cure, treatment consists of chemotherapy and radiation. In some cases, surgical resection or liver transplantation is performed.
• Paracentesis: When severe ascites -- swelling in the belly from liver failure -- causes discomfort, a needle can be inserted through the skin to drain fluid from the abdomen.
• ERCP (Endocscopic retrograde cholangiopancreatography): Using a long, flexible tube with a camera and tools on the end, doctors can diagnose and even treat some liver problems.