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The liver, located in the upper right quadrant of the abdominal cavity, is the largest organ in the body. It weighs approximately three to five pounds and is capable of storing about 300 ml of blood at any given time. The principle function of the liver is to filter and detoxify contaminants in the blood. The liver is also a critical metabolic and storage organ.
There are four lobes in the liver: right, left, caudate, and quadrate. The right and left lobes of the liver house lobules, the functional units of the liver. Lobules are clusters of hepatocytes surrounding a central vein. Each lobule is contained by vascular channels called hepatic sinusoids. The hepatic sinusoids nourish the hepatic cells within each lobule and separate the lobules from each other. The hepatic sinusoids are lined with Kupffer cells. Kupffer cells are phagocytes, capable of removing dead cells, bacteria, and foreign objects from the blood moving through the sinusoids.
When the liver is diseased, a number of important regulatory, metabolic, and storage function are compromised. Because of the important and expansive roles of the liver, a diseased liver results in serious illness. Among its major functions, the liver:
- Produces bile salts
- Metabolizes hormones
- Metabolizes drugs
- Synthesizes glucose
- Forms lipoproteins
- Converts carbohydrates and proteins to fat
- Deaminates proteins
- Synthesizes cholesterol
- Forms ketones from fatty acids
- Converts ammonia to urea
- Synthesizes plasma proteins
- Synthesizes clotting factors
- Stores glycogen
- Stores vitamins and minerals
- Filters and detoxifies blood
- Eliminates bilirubin
Cirrhosis
is a chronic degenerative condition of the liver characterized by progressive scarring and buildup of fibrous tissue. As the disease progresses, liver function declines. Cirrhosis is a leading cause of death among those aged 45-74 years. There are three types of cirrhosis: post-necrotic, biliary, and portal (alcoholic). Approximately 80 percent of cirrhosis cases are portal.(1) Although the major cause of portal cirrhosis is alcoholism, it also occurs among those who refrain from alcohol intake. Since the majority of alcoholics do not develop cirrhosis, other factors clearly play a role in the development of the disease.
During the development of cirrhosis, the liver undergoes several important alterations. First, fatty deposits develop on the liver. As alcohol displaces fat as fuel, fat that would normally be used as fuel begins to accumulate. Fat buildup in the liver causes it to enlarge, a condition known as alcoholic hepatitis. This enlargement leads to inflammation and destruction of hepatocytes. Lesions develop in patches throughout the liver. Eventually, the liver becomes scarred and distorted by bands of fibrous tissue. Liver function is destroyed and blood flow to the liver is obstructed.
Hepatitis is a term used to describe inflammation of the liver. Hepatitis can be a result of chronic alcohol abuse, certain medications, trauma, or viral infection. Viral hepatitis is caused by infection from one or more viruses, including hepatitis A, B, C, D, and E. These viruses all differ in nucleic acid structure, modes of infection, incubation, pathogenicity, and prognosis. All forms of viral hepatitis can cause acute illness; some may result in cirrhosis or carcinoma of the liver.
The danger of transmission of hepatitis is high. People can be chronically infected and asymptomatic, unwittingly passing the virus to others. Some may become asymptomatic carriers, never realizing they have been exposed. Those at greatest risk for transmission of viral hepatitis are health care workers and students, dentists, dental hygienists, and anyone regularly exposed to infectious diseases. Other than strict adherence to universal precautio
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