Name and explain the nine main functions of the liver? (Pg. 410)
1.) Synthesis of bile salts and secretion of bile. Bile salts play an important role in fat digestion and in the absorption of fat-soluble vitamins. Bile secretion is the main digestive function of the liver.
2.) Synthesis of plasma proteins. The plasma proteins play an important role in maintaining blood volume and controlling blood coagulation.
3.) Storage. The liver stores many substances: glucose in the form of glycogen, the fat-soluble vitamins (A,D,E, and K), and Vitamin B12.
4.) Detoxification. The liver plays an important role in the detoxification of drugs and other harmful substances. The liver changes these toxic substances into substances that can be more easily eliminated from the body by the kidneys.
5.) Excretion. The liver excretes many substances, including bilirubin, cholesterol, and drugs.
6.) Metabolism of carbohydrates. The liver plays an important role in the regulation of blood glucose levels. If blood glucose levels rise above normal, the liver takes the glucose out of the blood, converts it to glycogen, and then stores it for future use. If the blood glucose levels decline below normal, the liver makes glucose from glycogen and non-glucose substances (gluconeogenesis) and releases it into the blood.
7.) Metabolism of protein. The liver can make variety of different amino acids. Also, because only the liver contains the urea cycle enzymes, nitrogen (from ammonia) is converted to urea in the liver for eventual excretion by the kidneys. Free ammonia is toxic to humans.
8.) Metabolism of fats. The liver can break down fatty acids, synthesize cholesterol and phopholipids, and convert excess dietary protein and carbohydrates to fat.
9.) Phagocytosis. The kupffer cells are heptaic macrophages and can phagocytose bacteria and other substances.