1.Protein metabolism
The amino acids absorbed by the digestive tract are synthesized into protein in the liver, and the synthesized protein enters the blood circulation for the needs of organs and tissues throughout the body. The liver is the main site for the synthesis of plasma proteins, which can be used only for the renewal of proteins in various tissues in the body and play an important role in maintaining the body’s protein metabolism. The liver synthesizes ammonia, a toxic substance produced by protein breakdown and metabolism, into non-toxic urea, which is excreted from the body via the kidneys. Therefore, in patients with liver disease, plasma protein (such as albumin) decreases when liver function is impaired, while blood ammonia increases.
2.Glucose metabolism
Monosaccharides absorbed from the digestive tract are synthesized into hepatic glycogen in the liver and stored as energy. When labor, hunger, fever, blood sugar is consumed in large quantities, liver cells will break down liver glycogen into glucose and release it into the blood, mainly to provide energy for important organs. The average adult liver contains about 100 grams of liver glycogen, enough for 24 hours of fasting. The synthesis and decomposition of hepatic glycogen play an important role in regulating blood glucose concentration to maintain its stability, so it is easy to have hypoglycemic reaction or abnormal glucose tolerance when suffering from liver disease.
3.Fat metabolism
After digestion and absorption, part of the fat enters the liver for desaturation and catabolism, and then is transformed into body fat and stored. When hungry, the stored body fat can be transported to the liver first, and then decomposed for energy supply. The liver is one of the main organs for the synthesis of fatty acids, cholesterol and phospholipids in the body, and excess cholesterol is excreted from the body with bile. The various components of lipids in the body are relatively constant and their ratio is regulated mainly by the liver cells. When the fat metabolism is disturbed, fat can accumulate in the liver and form fatty liver.
4.Vitamin metabolism
The liver is the storage and metabolism site of vitamins A, C, D, E, K, B1, B2, B6, B12, folic acid, niacin and other vitamins. In particular, it is an organ for storing fat-soluble vitamins, for example, 95% of the body’s vitamin A is stored in the liver.
5.Heat production
When quiet, the body’s heat is mainly provided by the internal organs, and among the various internal organs, the liver is the organ with high metabolism in the body. For example, when quiet, the liver blood flow temperature is 0.4-0.8°C higher than that of the aorta, indicating that its heat production is greater.
6.Secretion of bile
Liver cells can continuously produce bile acid and secrete bile, which can promote the digestion and absorption of fat in the intestine and facilitate the absorption of fat-soluble vitamins A, D, E and K. When liver function is poor, the production and excretion of bile is impaired, and the fat in food is not easily digested and absorbed, often causing diarrhea and wasting.
7.Detoxification function
During the metabolic process of the body, the portal vein collects blood from the abdominal cavity, and the harmful substances and microbial antigenic substances in the blood will be detoxified and removed in the liver. The liver is the main detoxification organ of the body, which can protect the body from immune damage and make toxic substances into non-toxic or highly soluble substances, and then excreted with bile or urine, which is an important function for the body to maintain life.
8.Production of coagulation factors
The liver is the synthesis site of a variety of coagulation factors in the human body. There are 12 types of coagulation factors in the human body, four of which are synthesized in the liver, and fibrinogen and prothrombin, which are involved in blood clotting, are also synthesized in the liver. Therefore, liver disease is prone to prolonged coagulation and bleeding tendency.
9.Defense function
The liver has a strong ability to swallow bacteria, and 99% of the bacteria in portal blood are swallowed when they enter the liver. Therefore, the body’s defense ability decreases when suffering from liver disease, which can easily cause infection.
10.Hormone metabolism
Under normal conditions, various hormones in the blood are kept at a certain level, and the excess is processed by the liver to lose its activity. In liver disease, the fire extinguishing of estrogen, aldosterone and antidiuretic hormone may be impaired.