The liver, a wedge-sharped organ, is located underneath the rib cage. Weighing close to 3 pounds, it is the body's largest internal organ.The liver is an important organ that receives blood from two different sources. Many of the substances carried in the blood are modified as the blood passes through the liver.
The liver performs many varied and complex functions. It cleans and purifies the blood supply, breaks down certain chemical substances in the blood, and manufactures (synthesizes) others. The liver's four most important tasks are illustrated below.
Some chemicals are changed into harmless subtances.
Your body needs ways of getting rid of toxins. The liver is very important i this process. For example, any time you take medicine it's your liver's job to later remove the medicine from your blod -stream. If your liver isn't functioning correctly, the medicine may stay in your body bloodstream longer than it should.
Some toxins broken down by the liver are manufactured by the body itself. For example, the body normally produces a large ammount of ammonia in the intestines as food is being digested. the liver changes ammonia into urea, asubstance that is removed in the urine.
while breaking down and filtering toxins and waste products is good for the whole body,liver cells may be dmamged in the process. Detoxificatino of alcohol, for example, may harm the liver, leading to cirrhosis.
Simple building blocks are combined to manufacture complex substances.
The liver takes simple building blocks and combines them into larger units. For example, the liver manufactures most of the protiens found in the blood. One protien , called albumin, combines with other substances and carries them to wherever they are neede in the body . Protiens neccesary for prevention of bleeding are also manufactured in tha liver.
Sugar, fats and vitamins are stored in the liver until they are needed.
The liver changes blood sugar (glucose) into a storage from (glycogen). when the body needs energy, the sugar is then released by the liver.The liver also stores vitamins and minerals until they are needed in other areas of the body.
The body's esential building blocks are changed (transformed) to be used in other ways.
The liver uses enzymes to transform small building blocks (amino acids, sugars, and fatty acids) into ither building blocks.An excess of one of these enzymes , alanine aminotrans-ferase(ALT), is found in the blood when liver cells have been damaged.
The liver, which inactivates several hormones, regulates the amount of testerone and estogen in the blood. It also plays a major role in breaking down and building up cholestrol.
Liver disease may be detected during a physical examination. During the exam, your doctor will lightly tap your abdomen above the liver (per-cussion). The resulting sound may indicate a change in the size and position of the liver. He or She will also check the health of your liver by gently pressing the area near it. Anormal liver is neither shruken nor enlarged and is not tender when touched by the physician.
This picture shows what the normal liver looks like under a microscope.
A large blood supply is necessary to keep the liver functioning. Eighty percent of the liver's blood suppply (an estimated 3 pints per minute) is delivered via the portal vein, and the other 20% is delivered via the hepatic artery. The sinusoids then carry the blood to individuals liver cells.
If viral hepatitis infetion occurs, it may resolve on its own or become chronic. However, patients with chronic hepatitis often do not experience symptoms. On the other hand, others complain of excessice fatigue, weakness, and a capacity for exercise. Since liver damage may occur even in asymptomatic cases (no patient complaints), it is important to perform a biopsy and determine whether there is ongoing liver damage.
As chronic hepatitis progresses damage to the liver cells may impair liver function. The biopsy of the damaged liver shown here indicates cellular necrosis (death of liver cells), inflammation (cellular infiltration and swelling), and scaring (scar tissue beginning to replace functionning liver cells).
Chronic hepatitis can lead to cirrhosis or possibly even liver cance. in patients with cirrhosis, the liver begins to shrink in size and also hardens. Scarring of the liver also occurs. This change in the liver's structure may lead to a permanent impairment of liver function.
As cirrhosis worsens, almost all liver function is lost. The liver becomes even harder and smaller. Fluid accumulation in the abdomen and legs may occur. Bleeding from large veins in the intestinal tract is common and mental slowing also occur.
The severity of hepatitis is measured in two ways. The amount of inflammation present measures the current immune activity in the liver, and is known as the grade of the disease. When inflammation does not subside,it leads to destruction of working liver cells, when these cells die, they are replaced by scar tissue, a process known as fibrosis. The amount of scarring in the liver is used to determine the stage of hepatitis.The stage pf hepatitis represents the amount of liver damage that has been done by the disease. the more scarring that is present in the liver, the less work the liver can do.
These five sections of the liver represent increaing levels of fibrosis as defined by the METAVIR staging system. Little effect on liver function is seen during stages 0,1,and 2. Fibrosis is largely limited and most of the working cells of the liver stay well suppliced with blood and oxygen. By stage 3, however, the scarring has progressed to the point that the function of the liver cells is affected, and blood flow through the liver is altered. Fluids and bile may begin to build up in the liver, which begins to discolor. In stage4, also called cirrhosis, abnormal blood flow may result in a build up of fluid in the abdomen, a condition known as ascities. Failure of the liver cells to function often results in symptoms such as generalized weakness , anorexia, malaise, weight loss, and jaundice, ayellowing of the skin.