What is the Liver?

The liver is an important organ of the body

Healthy liver, artwork
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What is the liver? The liver is an important organ of the body that is responsible for detoxification, metabolism, synthesis and storage of various substances. The liver is crucial to life. Without it, a person couldn't live more than 24 hours.

Size and shape of the Liver

The liver is the largest internal organ in the body (the skin is considered the largest organ in the entire body) and it weighs about 3 pounds (1500g).

This reddish-brown organ is located just under the ribs in the right upper part of the abdomen, below the diaphragm. Most of the liver is protected by the rib cage, but it is possible for doctors to feel the edge of it by pressing deep into the abdomen when the patient inhales a big breath of air.

There are two lobes on the outside of the liver, a larger right lobe and smaller left lobe. A band of connective tissue divides the lobes and secures the liver to the abdominal cavity.

Liver tissue is made up of tiny units of liver cells. In between those cells, numerous canals carry blood and bile (fluid made and released by the liver and stored in the gallbladder).

Processes of the Liver

Nutrients, medication and other substances -- including toxic substances -- travel through the blood to the liver. Once there, these substances are processed, stored, altered and detoxified. They then either pass back into the blood or are released in the bowel.

With the help of vitamin K, the liver also produces proteins that help with blood clotting. The liver is also one of the organs that breaks down old or damaged blood cells.

Metabolism in the Liver

The liver plays a key role in the metabolism of fats, carbohydrates and proteins. In fat metabolism, the liver breaks down fats and produces energy.

It also produces bile, a yellow, brownish or olive-green liquid which helps break down and absorb fats.

In the metabolism of carbohydrates, the liver helps keep the level of sugar in your blood constant. When you eat, and your blood sugar rises, the liver removes sugar from blood and stores it in a form called glycogen. If your blood sugar is too low, the liver breaks down the glycogen and releases sugar into the blood. The liver also stores vitamins and minerals (iron and copper), and releases them into the blood when needed.

In the metabolism of proteins, liver cells change amino acids in foods so that they can be used to produce energy, or make carbohydrates or fats. This process creates a toxic substance called ammonia. The liver takes this ammonia and turns it into a much less toxic substance called urea, which is released into the blood. Urea then travels to the kidneys and moves out of the body in urine.


PubMed Health [Internet]. (Updated Nov. 22, 2012) "How does the liver work?" National Institutes of Health. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072577/

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