The human liver is an organ that has many functions and jobs within the body. It is a part of the digestive system, and it is responsible for everything from cholesterol production to waste filtering. It is vitally important to overall health and should be taken care of to avoid life-threatening diseases that can develop if a liver becomes overworked or unhealthy.
The liver is a part of the digestive system, but it does much more than simply process food intake. It is responsible for producing substances that will break down fats and lipids, making foods more digestible. It also produces several amino acids, which are essential to protein production, without which a body could not function. The liver produces much of the cholesterol in a body, whether healthy or unhealthy. Aside from the liver's production abilities, it also acts as a filter. When a harmful substance is taken into the body, the liver is the organ responsible for filtration. For example, the liver filters alcohol out of the blood. Simply stated, the main function of the liver is to keep an equilibrium in the body. It neutralises toxins that are harmful, it creates substances that are necessary and it disposes of waste products.
The liver is composed of an intricate network of blood vessels, capillaries and metabolic cells. The two major blood vessels connected to the liver, the hepatic artery and the portal vein, are responsible for carrying blood to the liver. The hepatic artery brings oxygenated blood from the heart so that the liver stays healthy and functioning. The portal vein brings blood with digested food particles in it from the small intestines, which the liver then filters and turns into carbohydrates, amino acids or waste products. The actual production of essential chemicals happens in the metabolic cells, which are grouped together in structures called lobules. There are thousands of these lobules in the liver, all of which work to produce and filter different substances.
The liver has four distinct lobes, each responsible for a different function.
The liver is a reddish-brown organ that is found on the right side of the abdominal cavity, just underneath the diaphragm. The colouring of the liver can be explained because of the great amount of blood being transported through it continuously. It is wedge-shaped, it usually weighs about 1.36kg. and it is divided into four lobes. These lobes are different shapes and sizes, and they are responsible for different functions within the liver. These lobes are called the right lobe, the left lobe, the quadrate lobe and the caudate lobe. They are separated and held together by ligaments and connective tissue.
Since the liver is an organ that has potentially hundreds of tasks to complete, and since it deals with complex and sometimes dangerous chemicals, diseases of the liver can be common. The most common of these diseases is cirrhosis, which is a scarring and hardening of liver tissue. Cirrhosis is caused by bacterial or viral infections, but also by alcohol abuse. Cirrhosis leads to an inability of the liver to function properly. In these cases, the liver will eventually become unable to produce the proteins that the body needs, and it will be unable to filter out toxins. Hepatitis, another common liver disease, is an inflammation of the liver that is caused by either a viral infection or alcohol abuse. Drugs can also cause major liver problems, since an overdose of drugs will overwhelm the liver and it will not be able to fully filter out toxins. Many of these diseases and conditions will eventually lead to liver failure, the only known cure for which is a liver transplant.
In recent years, there has been an emphasis in the medical community on finding more effective forms of liver transplants for patients with liver failure. Aside from traditional liver transplants, which can sometimes be rejected by the bodies of patients, other alternatives have been developed which incorporate both biological and non-biological elements. For example, along with a standard liver transplant, a non-biological system can be used to help in the filtration duties of a new or damaged liver. Biological approaches are also being developed. These include partial transplants, which would mean that a living donor could give a portion of their healthy liver to a patient with liver failure. It has also been suggested that the livers of pigs, which have similar organ structures to those of humans, could be used in situations where a human liver donation cannot be acquired in time. These techniques, and many others, are being researched and perfected.
- http://11uexcretorysystem.files.wordpress.com/2008/04/liver-abdomen.jpg, http://www.biomed.metu.edu.tr/courses/term_papers/bioartf-liver_kenar.htm