Stomach: structure. Participation in digestion

General scheme of digestion

To maintain normal metabolism, the human body requires a constant renewal of the resources expended in the form of organic compounds, vitamins, macro- and microelements. The respiratory system delivers only the molecules contained in the air, the rest of the substrates a person receives with the help of the digestive system. However, if the absorption processes occur in the intestine and partially in the oral cavity, the mechanical and chemical processing of the food obtained is carried out by the stomach. The structure of its walls ensures the splitting of macromolecules into smaller parts for better digestion in the intestine and promotes the chyme to the underlying gastrointestinal tract. However, in the acidic environment of this body, the enzymes responsible for the breakdown of carbohydrates are inactivated, so after the evacuation of the food lump further chemical processes proceed in the duodenum. This prevents the regurgitation of chyme back into the stomach: the structure of its second sphynctrum can be reduced immediately after the end of evacuation. And by the time nutrients reach the small intestine, almost all of them will be presented in the form of dimers, monomers and ions that can pass through intestinal villi and suck in the blood.

How is it arranged?

The structure of the human stomach can be represented in the form of a hollow muscular sac with two main sections: cardiac (including the vestibule, bottom and body) and pyloric (consisting of sequentially located pylorus cave and canal). Next, the latter is reported with a lumen of the duodenum. And to ensure proper food movement along the tract, the stomach has two sphinctra: gastroesophageal, which prevents return to the esophagus, and m. Sphincter pylori, which protects the duodenum from the acidic medium that the stomach has. The structure of its wall includes covering cells. They actively produce hydrochloric acid to swell proteins, activate enzymes, kill infectious substances in the food lump and start its evacuation. Also these cells synthesize and so-called. The internal factor of the Castle, which has anti-anemic activity.

A few words about others

Parietal cells of the stomach produce pepsinogens, and mucocytes - mucus, creating a natural barrier against the effect of HCl on the stomach. The structure of the muscular wall is three-layered: the myocytes have a longitudinal, transverse and oblique direction. They show the greatest activity at the standing of the person standing and practically zero - in the lying state. Also, the peristalsis is stimulated by the tension of the muscles of the abdominal press. Thus, the structure and functions of the stomach are extremely important in the process of digestion. Therefore, with partial resection of this organ or hyper / hypo / asecretion of hydrochloric acid and gastric juice, all further steps are blocked - and a syndrome of gastric dyspepsia occurs. And if the barrier mechanisms are insufficient, gastritis develops, and later a stomach ulcer.