Bile - a product of the activity of hepatocytes (liver cells).Various studies suggest that without the participation of bile in the digestion of food can not be the normal activity of the gastrointestinal tract.There are violations not only of the process of digestion and metabolism but if there is a failure in its formulation or its composition changes.
What is bile?
It is a digestive juice that is produced by the liver.It is used once or deposited in the gallbladder.It noted two important functions of biologically active liquid.She:
- helps digestion of fats and their absorption in the intestine;
- takes waste products from the blood.
physical properties
human bile has an intense yellow color, turning into greenish-brown (due to the decomposition of dyes).It is transparent, more or less viscous depending on the duration of time spent in the gallbladder.It has a strong bitter taste, a smell, and after a stay in the gallbladder is alkaline.Its share is about 1005 in the bile ducts, but it can grow to 1030 after a long stay in the gallbladder, due to the addition of mucus and some components.
components
Bile composition which is a composition of the following materials: water (85%), bile salts (10%), mucus and pigments (3%), fat (1%), inorganic salts (0.7%) andcholesterol (0.3%), stored in the gallbladder and released into the food after the small intestine through the bile duct.
There liver and gallbladder bile, the composition of the same, but different concentrations.In the study, it was observed the following substances:
- water;
- bile acids and their salts;
- bilirubin;
- cholesterol;
- lecithin;
- sodium, potassium, chlorine, calcium;
- bicarbonates.
in gallbladder bile of bile salts to 6 times more than in the liver.
Bile acids
chemical composition of bile is mainly represented by bile acids.Synthesis of these materials is the main mode of catabolism of cholesterol in mammals and man.Some of the enzymes involved in the development of bile acids, are active in many cell types of the body, but the liver - is the only body where they are a complete transformation.Bile acids (synthesis thereof) is one of the dominant mechanisms for the excretion of excess amounts of cholesterol.
However, excretion of cholesterol in the form of bile acids is not enough to completely neutralize the excess supply of its food.Although the formation of these substances is a path cholesterol catabolism, these compounds are also important in the solubilization of cholesterol, lipids, fat-soluble vitamins and other necessary substances, thus facilitating their delivery to the liver.The whole cycle of formation of bile acids requires 17 individual enzymes.Many bile acid metabolites are cytotoxic agents, so their synthesis must be tightly controlled.Some inborn errors of metabolism due to their defective genes responsible for the synthesis of bile acids, which leads to liver failure in early childhood and progressive neuropathy in adults.
Recent studies have shown that bile acids are involved in the regulation of its own metabolism, regulate lipid metabolism and glucose metabolism, responsible for the control of various processes in liver regeneration, and also regulate the overall energy consumption.
main functions
Many different substances contain bile.Its composition is such that there are no enzymes in other digestive juices from the stomach.Instead, it consists mainly of bile salts and acids that can:
- emulsified fats and break them into smaller particles.
- helps the body absorb the breakdown products of fat in the intestine.Salts of bile acids bind to lipids and is then absorbed into the bloodstream.
Another important function of bile is that it contains the destroyed red blood cells.This is bilirubin, and usually it is formed in the body to get rid of old red blood cells, hemoglobin-rich.Bile also transports excess cholesterol.It not only is the product of secretion of the liver, but also displays various toxic substances.
How does?
specific composition and functions of bile enable it to act as a surfactant by helping to emulsify fats in food just as the soap dissolves fat.Bile salts are hydrophobic and hydrophilic end.When exposed to water, mixed with the fat in the small intestine, bile salts accumulate around the oil drop and bind both water and fat molecules.This increases the surface area of fat, providing greater access pancreatic enzymes that break down fats.Since bile increases the absorption of fat, it helps in the absorption of amino acids, cholesterol, calcium and fat-soluble vitamins such as D, E, K and A.
Alkaline bile acids are also able to neutralize the excess acid intestines before it enters the ileum tothe end portion of the small intestine.Bile salts have a bactericidal effect, killing plurality microbes which may be present in the incoming food.
bile
liver cells (hepatocytes), produces bile, which collects and drains the bile duct.From there it passes to the small intestine and immediately begins to affect or fats accumulate in the bladder.
liver produces from 600 ml to 1 liter of bile for 24 hours.The composition and properties of bile change when it passes through the bile duct.Mucous water secretes these formations, and sodium bicarbonate, thereby diluting the hepatic secretion.These additional ingredients help neutralize stomach acid that enters the duodenum from the partially digested food (chyme) from the stomach.
Storage bile
liver secretes bile continuously: up to 1 liter per 24-hour period, but most of it is stored in the accumulator - the gall bladder.This concentrates the hollow body through its resorption water, sodium chloride and other electrolytes in the blood.Other components of bile salts such as bile acids, cholesterol, lecithin, bilirubin and remain in the gall bladder.
concentration
The gallbladder concentrates bile because it can store bile salts, and waste products from the liquid produced by the liver.Such components such as water, sodium, chloride and electrolytes, and then diffuse through the bladder.
Studies have shown that the composition of human bile in the bladder is the same as in the liver, but is 5-20 times more concentrated.This is because the gallbladder bile consists essentially of bile salts, and bilirubin, cholesterol, lecithin, and other electrolytes during the stay in the tank are absorbed into the bloodstream.
bile
After 20-30 minutes after eating partially digested food enters the duodenum 12 from the stomach to form chyme.The presence of food, especially fat in the stomach and duodenum stimulates the gall bladder to contract, which is due to the action of cholecystokinin.Gall bladder expels bile and relaxes the sphincter of Oddi, thereby allowing it to fall into the duodenum.
other incentives to reduce the gallbladder - a nerve impulses from the vagus nerve and the enteric nervous system.Secretin that stimulates pancreatic secretion also increases bile secretion.Its main effect is to increase the secretion of water and sodium bicarbonate in the bile duct mucosa.This sodium bicarbonate together with pancreatic bicarbonate needed to neutralize the gastric acid in the gut.
The bile contains a variety of substances - proteins, amino acids, vitamins and many others.
It should be noted that different people have individual bile qualitative and quantitative composition, i.e. different in content of bile acids, bile pigments and cholesterol.
clinical significance
In the absence of bile fats become indigestible and unchanged in the feces stand out.This condition is called steatorrhea.Cal instead of the characteristic brown color is painted in white or gray color and becomes fat.Steatorrhea can lead to deficiencies of nutrients: essential fatty acids and vitamins.In addition, the food passes through the small intestine (which is usually responsible for the absorption of fat from the food) and modifies the intestinal flora.It should be known that the large intestine is not occurring fat refining process, which leads to various problems.
The composition of bile include cholesterol, which is sometimes pressed to bilirubin, calcium, forming gallstones.These concretions are usually treated by removal of the bladder.However, they can sometimes be dissolved drug by increasing the concentration of certain bile acids such as ursodeoxycholic and chenodeoxycholic.
on an empty stomach (after repeated vomiting, for example), the color of vomit may be green or dark yellow and bitter.This is the bile.Composition of vomit often supplemented by normal digestive juices from the stomach.Color bile often compared with the color "cut grass", in contrast to the components in the stomach, which look greenish-yellow or dark yellow.Bile can enter the stomach of a weakened valve, when taking certain drugs and alcohol or under the influence of powerful muscle contractions and spasms of the duodenum.
Research bile
separate sensing method investigating the bile.The composition, quality, color, density and acidity different portions provides an indication of irregularities in the synthesis and transport.
