DK Science: Liver
The liver has many important jobs in the body. It produces the digestive juice bile and processes nutrients to be used by the body. It plays a role in regulating blood sugar levels and stores many important substances such as iron and some vitamins. Other functions of the liver include making proteins needed for blood clotting, breaking down old red blood cells, and removing or breaking down any toxic substances that appear in the blood.
The liver is situated mainly on the right side of your upper abdomen. One part of it partially covers the front of the stomach. It is the body’s heaviest internal organ, weighing up to 1.6 kg (3 1/2 lb) in an adult.
The liver consists of a large right lobe and smaller left lobe. It receives blood from two sources: the hepatic artery and portal vein. Blood leaves the liver in the hepatic veins. Outside the liver, these join a large vein that carries the blood back to the heart. Emerging from beneath the liver is a duct that carries the bile made by the liver to the gall bladder.
There are thousands of tiny processing units, called lobules, in the liver. Blood flows through channels called sinusoids in a lobule, past groups of liver cells, and towards a central vein. As the blood flows past, the liver cells absorb some substances from it. They also release other substances into the blood.
The gall bladder is a small sac that lies beneath the liver. The gall bladder stores bile made by the liver and releases the bile into the small intestine when food enters the intestine from the stomach. Bile is a greenish fluid made of material produced from the breakdown of old red blood cells. It plays a key role in fat digestion.