Functions of bile in digestion

Bile is the secret of liver cells of hepatocytes. It accumulates in the small bile ducts, and then enters the common duct and through it into the gallbladder and 12-colon. Functions of bile for the body are of great importance. One of its main functions is participation in digestion processes.

Where does bile accumulate?

The gallbladder is a storage tank for bile. During the active phase of digestion, when partially digested food comes from the stomach to the 12-colon, the maximum amount is also allocated there. The main functions of human bile are participation in digestion and stimulation of secretory activity and motility of the small intestine, which also provides processing of the food lump.

Bile, which is released into the digestive tract from the gallbladder, is called mature, and is secreted directly by the liver - young, or liver.

The process of bile and bile secretion

The process of secretion of hepatocytes (choleresis) occurs continuously. They filter a number of substances from the blood into the bile capillaries. Further, due to the reabsorption of water and mineral salts, the final composition of this secretory fluid takes place. This process is carried out in the bile duct and gall bladder. Part of the bile immediately enters the intestine, it is called liver, or young. But the bulk of it accumulates in the gallbladder, where it moves along the bile ducts. The bile bile accumulates, becomes thick and concentrated. It is darker than liver.

During the day, the liver cells in an adult develop about two liters of secretion. On an empty stomach he practically does not enter the intestine. After eating, biliary excretion (cholecinosis) occurs in the 12-colon. There, bile performs a digestive function, as well as bacteriostatic and regulatory. That is, it is itself a regulator of the process of bile formation and bile secretion.

Thus, the more bile acids released into the portal bloodstream (portal vein), the higher their concentration in the bile composition and, accordingly, less is synthesized by hepatocytes. Functions of bile and pancreatic juice are basic in digestion.

Bile composition

The main component of bile is bile acids. Most (67%) are cholic acid and chenodeoxycholic. The remaining acids are secondary, that is, the derivatives of these two acids: deoxycholic, allocholic, lithocholic and ursodeoxycholic.

All bile acids are in this secret in the form of compounds with taurine and glycine. The content of a large number of sodium and potassium ions gives the bile an alkaline reaction.

In addition, the composition of bile includes some organic substances :

• Phospholipids.
• Protein compounds, namely, immunoglobulins A and M.
• Bilirubin and biliverdin (bile pigments).
• Cholesterol.
• Mucin.
• Lecithin.

And also ions of some metals (zinc, copper, lead, magnesium, indium, mercury), vitamins A, B, C.

All these components are included in the composition of both the hepatic and gallbladder, but in the first their concentration is about 5 times lower than in the second.

Functions of bile

Basically, they are associated with the work of the gastrointestinal tract. Functions of bile in digestion are associated with a number of enzymatic reactions.

1. Under its influence, emulsification of fats occurs, thereby contributing to their absorption.
2. It neutralizes the harmful effects of pepsin (the main component of gastric juice), which is capable of destroying the enzymes of the pancreas.
3. Activates the motility of the small intestine.
4. Stimulates the production of mucus.
5. Activates the production of gastrointestinal hormones: secretin and cholecystokinin, which are produced by cells of the small intestine and contribute to the regulation of the secretory work of the pancreas.
6. Prevents the adhesion (adhesion) of bacteria and protein components.
7. Has an antiseptic effect on the intestines and takes part in the formation of feces.

Thus, the function of bile in digestion can not be overestimated. It is through the bile that the digestive process started in the stomach continues and ends safely in the intestine.

The importance of bile for the human body

So, we found out that the main functions of bile are related to the digestive process. What happens if, for some reason, the composition of bile changes or it does not enter the digestive tract? Lack or absence of it leads to serious pathologies:

• Gallstone disease.
• Steatorei.
• Gastroesophageal reflux disease (GERD), etc.

Cholelithiasis

This pathology can occur due to an unbalanced composition of bile. This bile is called lithogenic. Such properties, it can acquire with regular errors in the diet, namely, if the animal food is dominated by animal fats. Functions of liver bile may be disrupted as a result of endocrine diseases. In addition, the lithogenic properties of this liver secret can be acquired as a result of a violation of lipid metabolism, which, as a rule, is accompanied by an increase in the patient's body weight. The cause of the change in the composition of bile may also be infectious and toxic damage to the liver or an inadequately active lifestyle (hypodynamia).

Steatorrhea

As mentioned above, bile functions are associated with fat emulsification. If, for some reason, bile ceases to enter the small intestine, there is no absorption of fat, and they begin to stand out with feces. The same can occur if there is a deficiency in this hepatic secretion of bile acids (a change in its composition). In this case, the feces acquire a white or gray color and a greasy consistency. This pathology is called steatorrhoea. With this disease, the body lacks essential fat, fatty acids and some vitamins. Because of the steatorrhoea, the lower parts of the intestine suffer, because they are not adapted to such a chyme.

How is bile examined?

In order to investigate the composition and function of bile, a fractional multimodal duodenal sounding method is used. This procedure consists of five steps:

1. Basal secretion of bile - secretion of the common bile duct and 12 duodenal ulcer occurs. Lasts about 15 minutes.
2. The phase of the secretory pause or closed sphincter of Oddi. The duration of this phase is 3 minutes.
3. The phase of allocation of residual bile of portion A. Lasts about 5 minutes.
4. The phase of allocation of a bubble bile of portion B. This period lasts about 30 minutes.
5. Isolation of bile hepatic - portion C. This phase lasts approximately 20 minutes.

Thus, 3 bile portions are obtained. All of them differ in composition. The most concentrated bile is bile - a portion of B. It contains the largest amount of fatty acids, bilirubin and other bile components.

This method of investigation allows you to determine the physical properties of bile, its composition, the volume of the gallbladder, the state of the biliary tract and to identify the localization of the pathological process.