Organs of digestion: to digest and assimilate
Digestion - a process that we all do unconsciously, this is the body itself at the reflex level. This process is complicated, so the question of an inquisitive person "What is digestion?" Is legitimate. From the doctor's point of view, this is a process of food processing, physical and chemical. As a result, it becomes possible to absorb substances, as well as waste disposal.
Digestive organs are the communicating hollow organs, supplemented with glands, which help to destroy chemical bonds in substances. For example, carbohydrates of potatoes and carbohydrates of bread are in the form of starch, they can not be digested until the starch molecules are destroyed to glucose. The protein of meat, too, can not be assimilated by itself - it is necessary to decompose it into constituents - amino acids( from which the body can build its own protein).Fats themselves can not appear inside the body's environment - only after they are digested fatty acids and glycerin.
The physiology of digestion is such that substances that are inside the body are not in the body. For this they have to undergo many transformations. And then through thin mucous there is an absorption. Organs of digestion include also the liver, salivary glands and pancreas. In addition, in the wall of the digestive organs there are glands producing substances necessary for digestion. All walls are covered with mucus, thus reducing the likelihood of injuring delicate shells.
Mechanically, the food is treated with teeth, then it is mixed with saliva. Saliva is secreted by three pairs of large glands and many small ones. In this liquid there are organic components, minerals and products of decay of leukocytes. But the main thing - it contains two enzymes - ptyalin( cleaves starch) and maltase( splits sugar of rye, barley, etc.).From the mouth through the throat, food enters the esophagus.
Esophagus is a tube that can be called quite straight. It is covered with multilayered flat epithelium. These cells are constantly updated, as they are very easy to injure. The division takes place in the deep layers, while the outer part is sloughed and dropped into the stomach along with the food. In the submucosa there is a small number of glands - the esophagus gland. Near the stomach they are similar to the excreted substance on the stomach, they bear the name of the cardiac glands. At the beginning of the esophagus there are many striated muscles, but in the lower third there are only smooth muscle fibers. The swallowing process begins consciously, but then the reflex response is turned on. After the esophagus, food is taken up by such digestive organs as the stomach and intestines.
Stomach works as an excellent mixer due to its developed musculature. In this body, protein digestion begins with the enzyme pepsin, the bacteria are killed with hydrochloric acid. As a result of digestion in the stomach, a semi-liquid, evenly chopped, chyme content is obtained. Some salts, water, alcohol, some medicines are also absorbed from it. The stomach produces an anti-anemic factor.
After food enters the small intestine. Its length is on average six meters. The first 30 cm is the duodenum. It is attached to neighboring organs and goes around the head of the pancreas. Then passes into the skinny, and then the ileum. In the small intestine, the process of digestion is completed, and selectively digestive products are absorbed into the blood and lymph. In the small intestine there are special formations - villi, which greatly increase the suction area. In this section of the intestine, the ducts from the liver( bile) and the pancreas flow. As a result, it is here that carbohydrates, fats and proteins are finally digested and digested. And fats come immediately to the lymph, which then connects to the blood.
In the large intestine, digestion of the residues is completed, but already "for themselves" putrefactive bacteria. The water is sucked in, and the remainders of the food acquire a consistency of feces. In the final section, the rectum of the vital activity awaits the possibility of being removed in the process of defecation. Thus ends the process of digestion of food. It is important for all the digestive organs, only their coordinated work is able to help the cells of the body to be updated due to the availability of building material for cells.