The liver, located in the right upper abdomen, is the largest internal organ in the body. The liver is part of the digestive system. Secretions are carried from the liver by hepatic ducts into the gall bladder and the common bile duct shared by the pancreas and finally into the duodenum of the small intestine. The liver comprises two major lobes, a large right and a smaller left lobe. Lobes are further divided into tiny hepatic (liver) lobules of hepatic cells.
The liver serves as a storage site in the body. Carbohydrates are broken down into simple sugars during digestion and enter the blood stream as glucose. When the glucose level gets too high, the pancreas releases insulin to signal the liver to store excess in the form of glycogen. The liver also stores some vitamins, such as A, D and B12, and extra iron in the form of ferritin until iron levels drop.
When the body needs glucose (sugar) energy, the pancreas releases glucagon, which causes the liver to convert the stored glycogen back into glucose. If there is not enough glycogen stored (as can occur with diabetes), the liver can convert fat or protein into glucose to try to meet the body's energy needs for glucose.
The liver regulates the amount of lipids (fats) circulating in the body and controls the amount of cholesterol, which is used to produce bile salts. Bile salts, bile pigments and cholesterol combine to form bile, which is stored in the gallbladder and released into the duodenum of the small intestine to aid in the digestions of fats and proteins. Bile salts emulsify fat globules to make them easier for the body to absorb.
The liver converts plasma proteins into amino acids, such as albumin, to help maintain pressure in vessels and carry lipids and fat-soluble vitamins. The liver converts some amino acids into urea, a form that can be excreted as waste by the kidneys. The liver also converts some protein into fibrinogen, which is essential for clotting of the blood to prevent excess bleeding
The liver filters damaged and dead red blood cells and other foreign material (bacteria) and toxins (e.g., alcohol or drugs) from the blood. According to R. A. Bowen, Ph.D, of the Department of Biomedical Sciences at Colorado State, the red blood cells break down into bilirubin and become part of the bile pigment in the bile, carried into the small intestine and expelled in feces. The liver produces about a pint or more of bile daily.