It is a large organ with many regulatory and storage functions. The liver is
situated in the upper abdomen, and weighs about 2 kg/4.5 lb. It is divided into
four lobes. The liver receives the products of digestion, converts glucose to
glycogen (a long-chain carbohydrate used for storage), and breaks down fats.
It removes excess amino acids from the blood, converting them to urea, which
is excreted by the kidneys. The liver also synthesises vitamins, produces bile
and blood-clotting factors, and removes damaged red cells and toxins such as
alcohol from the blood.
Weight about four pounds, the liver is the largest gland of the body
and the only organ that will regenerate itself when part of it damaged. Up to
25 percent of the liver can be removed, and within a short period of time, it
will grow back to its original shape and size.
The liver has many functions, perhaps the most important of which is its
secretion of bile. This fluid is stored in the gallbladder for release when
needed for digestion. Bile is necessary for the digestion of fats; it breaks
fat down into small globules. Bile also assists in the absorption of fat soluble
vitamins A, D, F, and K, and helps to assimilate calcium. In addition, bile
converts beta-carotene to vitamin A. It promotes intestinal peristalsis as
well, which helps prevent constipation.
After food has been absorbed into the bloodstream through the intestinal
wall, it is transported by way of the hepatic portal system to the liver.
In the liver nutrients such as iron and vitamins A, B12 and D are extracted
from the bloodstream and stored for future use. These stored substances are
utilised for everyday activities and in times of physical stress. In addition,
the liver plays an important role in fat metabolism, in the synthesis of fatty
acids from amino acids and sugars, in the production of lipoproteins, cholesterol,
and phospholipids, and in the oxidation of fat to produce energy. Finally,
excess food in converted to fat in the liver, which is then transported to
the fatty tissues of the body for storage.
The liver also acts as a detoxifier. Protein metabolism and bacterial fermentation
of food in the intestines produces the by-product ammonia, which is detoxified
by the liver. The liver regulates protein metabolism. In addition to detoxifying
ammonia, the liver also combines toxic substances including metabolic waste,
insecticide residues, drugs, alcohol, and chemicals with other substances
the are less toxic. These substances
are then excreted from the kidneys. Thus in order to have proper liver function,
you must also have proper kidney function. Physicians have found that when
either the liver of kidney appears to be malfunctioning, treating both organs
produces the best health results.
In addition to its many other functions, the liver is responsible for regulating
blood sugar levels by converting thyroxine, a thyroid hormone, into its more
active form. Inadequate conversion by the liver may lead to hypothyroidism.
The liver creates GTF(Glucose tolerance Factor) from chromium and glutathione.
GTF is required for insulin to regulate blood sugar levels properly. Excess
sugar will be stored in the body as glycogen, and then converted back to sugars
when needed for energy. The liver also breaks down hormones like adrenaline,
aldosterone, and estrogen, and insulin after they have performed their needed
functions.
The liver weighs about 3 pounds and is the largest organ in the body.
It is located in the upper right side of the abdomen, below the ribs. When chronic
diseases cause the liver to become permanently injured and scarred, the condition
is called cirrhosis.
The scar tissue that forms in cirrhosis harms the structure of the liver,
blocking the flow of blood through the organ. The loss of normal liver tissue
slows the processing of nutrients, hormones, drugs, and toxins by the liver.
Also slowed is production of proteins and other substances made by the liver.
Cirrhosis is the seventh leading cause of death by disease. About 25,000
people die from cirrhosis each year. There also is a great toll in terms of
human suffering, hospital costs, and the loss of work by people with cirrhosis
Cirrhosis has many causes. In the United States, chronic alcoholism is the
most common cause. Cirrhosis also may result from chronic viral hepatitis
(types B, C, and D).
Liver injury that results in cirrhosis also may be caused by a number of
inherited diseases such as cystic fibrosis, alpha-1 antitrypsin deficiency,
hemochromatosis, Wilson's disease, galactosemia, and glycogen storage diseases.
Two inherited disorders result in the abnormal storage of metals in the liver
leading to tissue damage and cirrhosis. People with Wilson's disease store
too much copper in their livers, brains, kidneys, and in the corneas of their
eyes.
In another disorder, known as hemochromatosis, too much iron is absorbed,
and the excess iron is deposited in the liver and in other organs, such as
the pancreas, skin, intestinal lining, heart, and endocrine glands.
If a person's bile duct becomes blocked, this also may cause cirrhosis. The
bile ducts carry bile formed in the liver to the intestines, where the bile
helps in the digestion of fat.
In babies, the most common cause of cirrhosis due to blocked bile ducts is
a disease called biliary atresia. In this case, the bile ducts are absent
or injured, causing the bile to back up in the liver.
These babies are jaundiced (their skin is yellowed) after their first month
in life. Sometimes they can be helped by surgery in which a new duct is formed
to allow bile to drain again from the liver.
In adults, the bile ducts may become inflamed, blocked, and scarred due to
another liver disease, primary biliary cirrhosis. Another type of biliary
cirrhosis also may occur after a patient has gallbladder surgery in which
the bile ducts are injured or tied off.
Other, less common, causes of cirrhosis are severe reactions to prescribed
drugs, prolonged exposure to environmental toxins, and repeated bouts of heart
failure with liver congestion.
People with cirrhosis often have few symptoms at first. The two major problems
that eventually cause symptoms are loss of functioning liver cells and distortion
of the liver caused by scarring. The person may experience fatigue, weakness,
and exhaustion. Loss of appetite is usual, often with nausea and weight loss.
As liver function declines, less protein is made by the organ. For example,
less of the protein albumin is made, which results in water accumulating in
the legs (oedema) or abdomen (ascites). A decrease in proteins needed for
blood clotting makes it easy for the person to bruise or to bleed.
In the later stages of cirrhosis, jaundice (yellow skin) may occur, caused
by the build-up of bile pigment that is passed by the liver into the intestines.
Some people with cirrhosis experience intense itching due to bile products
that are deposited in the skin. Gallstones often form in persons with cirrhosis
because not enough bile reaches the gallbladder.
The liver of a person with cirrhosis also has trouble removing toxins, which
may build up in the blood. These toxins can dull mental function and lead
to personality changes and even coma (encephalopathy).
Early signs of toxin accumulation in the brain may include neglect of personal
appearance, unresponsiveness, forgetfulness, trouble concentrating, or changes
in sleeping habits.
Drugs taken usually are filtered out by the liver, and this cleansing process
also is slowed down by cirrhosis. The liver does not remove the drugs from
the blood at the usual rate, so the drugs act longer than expected, building
up in the body. People with cirrhosis often are very sensitive to medications
and their side effects.
A serious problem for people with cirrhosis is pressure on blood vessels
that flow through the liver. Normally, blood from the intestines and spleen
is pumped to the liver through the portal vein.
But in cirrhosis, this normal flow of blood is slowed, building pressure
in the portal vein (portal hypertension). This blocks the normal flow of blood,
causing the spleen to enlarge. So blood from the intestines tries to find
a way around the liver through new vessels.
Some of these new blood vessels become quite large and are called "varices."
These vessels may form in the stomach and oesophagus (the tube that connects
the mouth with the stomach). They have thin walls and carry high pressure.
There is great danger that they may break, causing a serious bleeding problem
in the upper stomach or oesophagus. If this happens, the individual's life
is in danger, and action must be taken quickly to stop the bleeding.
The doctor often can diagnosis cirrhosis from the individual's symptoms and
from laboratory tests. During a physical exam, for instance, the doctor could
notice a change in how your liver feels or how large it is. If the doctor
suspects cirrhosis, he or she will recommend that you have blood tests.
The purpose of these tests is to find out if liver disease is present. In
some cases, other tests that take pictures of the liver (such as the computerised
axial tomography scan, ultrasound, and the radioisotope liver/spleen scan)
may be recommended.
The doctor may suggest that the diagnosis be confirmed by putting a needle
through the skin (biopsy) to take a sample of tissue from the liver.
In some cases, cirrhosis is diagnosed during surgery when the doctor is able
to see the entire liver. The liver also can be inspected through a laparoscope,
a viewing device that is inserted through a tiny incision in the abdomen.
Treatment of cirrhosis is aimed at stopping or delaying its progress, minimising
the damage to liver cells, and reducing complications.
In alcoholic cirrhosis, for instance, the person must stop drinking alcohol
to halt progression of the disease. If a person has hepatitis, the doctor
may administer steroids or antiviral drugs to reduce liver cell injury.
Medications may be recommended to control the symptoms of cirrhosis, such
as itching. Oedema and ascites (fluid retention) are treated by reducing salt
in the diet. Medications called "diuretics" are sometimes used to remove excess
fluid and to prevent oedema from recurring.
Diet and drug therapies can help to improve the altered mental function that
cirrhosis can cause. For instance, decreasing di-etary protein results in
less toxin formation in the digestive tract. Laxatives such as lactulose may
be given to help absorb toxins and speed their removal from the intestines.
The two main problems in cirrhosis are liver failure, when liver cells just
stop working, and the bleeding caused by portal hypertension. The doctor may
prescribe blood pressure medication, such as a beta blocker, to treat the
portal hypertension.
If the individual bleeds from the varices of the stomach or oesophagus, the
doctor can inject these veins with a sclerosing agent administered through
a flexible tube (endoscope) that is inserted through the mouth and oesophagus.
In critical cases, a liver transplant or another surgery (such as a portacaval
shunt) that is sometimes used to relieve the pressure in the portal vein and
varices may be an option.
Individuals with cirrhosis often live healthy lives for many years. Even
when complications develop, they usually can be treated. A few individuals
with cirrhosis have undergone successful liver transplantation.
It's important to remember, however, that all tests, procedures and medications
carry risks. To make an informed decision about your health, be sure to ask
your physician about the benefits, risks and costs of all procedures and medications.
