The liver has important and complex physiological functions in the body, such as synthesis, secretion, detoxification and immunity. The following is an introduction to each of them. I. Metabolic functions of the liver: synthesis and decomposition, secretion 1. The liver is involved in the metabolism of sugar, protein, fat, vitamins and hormones, etc. 2. The liver synthesizes all important proteins required by the body, including albumin, fibrinogen and prothrombin, etc. At the same time, the liver converts toxic substances produced by amino acid metabolism, such as ammonia, into non-toxic urea, which is excreted by the kidneys; 4. After lipids are absorbed into the lymphatic vessels through the intestine and enter the blood circulation, they are broken down and synthesized in the liver and transferred to the corresponding parts, thus maintaining the concentration and ratio of various lipids in the body; 5. In addition, the liver is involved in the metabolism of various vitamins: carotene enzymes in the liver can convert carotene into vitamin A and store it; the liver can also store B vitamins and vitamins C, D, E and K; 6. estrogen, antidiuretic hormone, aldosterone and other hormones have inactivating effects. When the liver function is impaired and the inactivation effect is reduced, the increase of estrogen in the body causes spider nevus, liver palm and gynecomastia; the increase of antidiuretic hormone and aldosterone causes swelling and ascites, etc. Detoxification and immune functions of the liver 1. In the process of human metabolism, some toxic substances such as ammonia and other foreign substances that need to be degraded or detoxified, including alcohol and drugs, are decomposed, oxidized or combined in the liver to make them lose their toxicity and excreted out of the body; 2. Kupffer cells in the liver can engulf and remove harmful substances such as bacteria and foreign substances in the blood, playing an important immune defense. Other functions of the liver 1. The liver also has the role of synthesizing coagulation substances and maintaining blood volume balance; 2. Fibrinogen, prothrombin, and coagulation factors V, VII, VIII, IX, X, D and Ⅻ required for the coagulation process are synthesized in the liver. Therefore, the liver is very important to the coagulation function of the human body; 3. The liver contains iron, copper and vitamin B12, folic acid and other hematopoietic components, which are indirectly involved in hematopoiesis. At the same time, the liver itself stores a large amount of blood and can export some of it to maintain the balance of circulating blood volume during acute bleeding.