In the process of digestion, through neuromodulation, the sphincter of common bile duct contracts, the gallbladder expands, and a pressure gradient is generated in the biliary tract. The bile secretion pressure was 2.933KPa(22 mm Hg), the hydrostatic pressure of common bile duct was1.46 kPa (11mm Hg), and the internal pressure of gallbladder was 0.400 ~ 0. 933 Pa (3 ~ 7 mm Hg). Due to the pressure difference, liver bile enters the gallbladder.
Bile storage mainly occurs on an empty stomach at night, but the sphincter is not completely closed and some bile still enters the small intestine. It is reported that only 50% bile enters the gallbladder on an empty stomach.
The volume of gallbladder is about 50 ml, and the storage of bile is increased by its concentration function. By absorbing 90% of the water in bile, about 500 ml of bile can be stored, and most of the bile acid pool can be stored in it. The research shows that the reverse electrochemical gradient absorption of sodium chloride by gallbladder mucosa is the function of sodium pump, and then the osmotic pressure difference is generated to absorb water, so that bile is concentrated by 5 ~ 20 times.
Gallbladder mucosa can absorb free bilirubin, free bile acid and lecithin, but the absorption of cholesterol is very limited. It has almost no absorption effect on bound bilirubin and bound bile acid.
Gallbladder contrast agent is secreted into liver and bile through liver cells and is not absorbed after entering gallbladder. After concentration, the gallbladder can be developed under X-ray, but it will not be developed when the gallbladder concentration function is damaged or the cystic duct is blocked.
The damage of gallbladder mucosa increases the absorption of contrast agent, which is also a factor that gallbladder does not develop. The PH value of gallbladder bile is lower than that of liver bile, which is due to the secretion of H+ and H+-Na+ exchange by gallbladder mucosa. It may also be that the gallbladder mucosa absorbed HCO3-, which acidified the gallbladder bile.
2. Empty bile
Gallbladder emptying also requires the interaction between gallbladder and common bile duct sphincter. When bile is emptied, gallbladder smooth muscle contracts and sphincter relaxes.
3. Adjust bile duct pressure
Gallbladder can regulate the internal pressure of bile duct, and the internal pressure of bile duct does not increase after 4 hours of common bile duct obstruction. However, after cholecystectomy, the common bile duct expands, the sphincter of the common bile duct weakens, the bile duct wall thickens, and the mucus glands increase to adapt to more bile discharged into the intestine.
Gallbladder and biliary system:
1. Bile storage: A hungry person (that is, during non-digestion), bile is stored in the gallbladder, and then discharged from the gallbladder when it needs digestion, so the gallbladder is called a "bile warehouse". At the same time, it plays a role in buffering biliary tract pressure.
2. Concentrated bile: Most of the water and electrolytes in golden yellow alkaline liver bile are absorbed by gallbladder mucosa and returned to the blood, so that the effective components in bile are stored in the gallbladder and become brown or dark green gallbladder bile, which is weakly acidic.
3, secretion of mucus: gallbladder mucosa can secrete 20ml of viscous mucus every day, protecting bile duct mucosa from erosion and dissolution of concentrated bile.
4. Emptying: After eating for 3 to 5 minutes, the food passes through the duodenum, which stimulates the duodenal mucosa and produces a hormone called cholecystokinin, which makes the gallbladder contract, and the bile in the gallbladder is immediately discharged into the duodenum to help the digestion and absorption of fat. At the same time, the bacteria in the biliary tract are excreted with bile. Generally speaking, after eating fat for half an hour, the gallbladder can be emptied.
The above contents refer to Baidu Encyclopedia-Gallbladder; Baidu encyclopedia-Dan