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Liver Anatomy and Function

Diagram showing location of liver
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The liver is found in the upper right-hand side of the abdomen under the ribs below the diaphragm. It is a dark reddish-brown organ that weighs about three pounds.

Liver Anatomy
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The liver has a right lobe and a left lobe. Blood enters the liver from the hepatic artery and the hepatic portal vein and leaves the liver from the hepatic vein. Inside the two lobes is a network of tubes, also called the biliary tree that carries bile from the liver to the intestine. Bile is a substance that helps carry away wastes and is needed for the breakdown and absorption of dietary fats. Each tube is called a duct. Smaller ducts connect to larger ducts. The larger ducts join to form the hepatic duct. This duct network allows bile to drain out of the liver.

What Does the Liver Do?

The liver has many functions. Some of the main functions are:

  • Storing vitamins, glucose for energy, and making proteins
  • Helping build muscles
  • Stopping cuts from bleeding (coagulation)
  • Killing germs, helping keep the body healthy (immune system)
  • Making bile to help digest foods
  • Keeping pollutants or toxins from hurting the body
  • Filtering medications, chemicals, and toxins from the body
  • Removing waste products of food breakdown

Cirrhosis

Liver cirrhosisCirrhosis is a condition where there is irreversible scarring of the liver. As scar tissue replaces normal tissue, blood flow through the liver is affected which can lead to some of the symptoms of cirrhosis. Cirrhosis can be without signs and symptoms in its early stages. But as liver function deteriorates symptoms appear such as: fatigue, exhaustion, nausea, unintended weight loss (especially in the upper body) swelling in the legs and abdomen, jaundice, and itching. Cirrhosis is characterized by widespread nodules in the liver and scar tissue.

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Complications of Cirrhosis

Ascites

Ascites is the presence of excess fluid inside the abdominal cavity. Inside the abdomen is a membrane called the peritoneum, which has two layers. One layer lines the abdominal wall and the other layer covers the organs inside the abdominal cavity. The peritoneum produces a fluid that acts as a lubricant and allows the abdominal organs to glide smoothly over one another. In cirrhosis too much of this fluid can build up between the two layers and this is called ascites. This causes the abdomen to become very large.

Portal Hypertension

In individuals without cirrhosis, blood is carried to the liver by a major blood vessel called the portal vein. If blood is unable to flow easily through the liver because of cirrhosis, the blood gets slowed down in this vein and the pressure inside the vein increases. This higher pressure in the portal vein is called portal hypertension.

When the blood does not flow normally through the portal vein, it must return to the heart using other blood vessels. These vessels become swollen because of the increased amount of blood flowing through them. They are called varices. These varices can occur in the esophagus (food tube) or in the stomach. Varices have thin walls and can easily break open because they are not meant to handle such high-pressure blood flow. Bleeding from a broken blood vessel is serious and can even be fatal. These varices are most commonly diagnosed by an esophagogastroduodenostomy (EGD).

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Encephalopathy

The exact cause of the disorder is unknown. However, when the liver cannot properly breakdown and detoxify substances in the body, toxic substances build up in the bloodstream. One substance believed to be particularly toxic to the central nervous system is ammonia, which is produced by the body when proteins are digested, but is normally detoxified by the liver. Many other substances may also accumulate in the body and contribute to dysfunction of the nervous system.

In people with otherwise stable liver disorders, hepatic encephalopathy may be triggered by episodes of gastrointestinal bleeding, excessive intake of dietary protein, electrolyte abnormalities which can result from vomiting or diarrhea, infections, renal disease.

Encephalopathy can be worsened by the use of sedatives or narcotics so patients with liver disease are instructed not to take these medications. Encephalopathy can be monitored by using a psychomotor test called a Trail Test as well as by family observing for behavior changes.