Food processing by the gastrointestinal tract

Nutrition is the most complex combination of processes within our body. This is the processing of food, the process of its assimilation and absorption of nutrients, replenishment of energy and so on. All this happens when we simply eat. Let's learn more about the structure of the gastrointestinal tract.

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Process of processing and assimilation of food

The main processes of food processing occur as a consequence of digestion inside our digestive system. These are all organs whose role, in general, is to process food by chemical means. Also, the digestive system promotes the qualitative absorption of nutrients and stops the entry of harmful food components, neutralizes and removes them.

Due to the work of the gastrointestinal tract, food is decomposed to elementary (including chemical) compounds. This happens for the best digestion of food. The digestive tract works like a food processor and tirelessly chops all the food consumed by a person, releases juices for processing and mixes, chemically treats, through which the gastric juices cope with the large quantities of food that you eat daily.

Sometimes it is very difficult for the reader to realize how the food you use can support the functionality and vital activity of the whole organism, feed it with useful substances. Now, in a simple form of presentation, we will try to place everything "on the shelves" and tell about the physiological process of digestion and processing of food by different parts of the digestive tract.

Oral cavity

The oral cavity also refers to the gastrointestinal tract. Starting from the oral cavity, the food that you eat begins to migrate through the body and be digested and processed. With the help of the tongue and teeth, the food is mixed and crushed to a uniform consistency, then the salivary glands go into the attack, with the help of which saliva enters the oral cavity, it moistens the food.

With the help of salivary enzymes, called amylase, food begins to decompose. Then a person performs a complex reflex function - swallowing. Thanks to swallowing, food enters the esophagus.

If a person chews the food badly, she is still not ready for digestion. The food should be thoroughly chewed and crushed, if it is not so, a person can get gastritis, constipation and suffer from other problems of the digestive tract.

Esophagus

Esophagus is a kind of corridor so that a lump of food normally passes from the oral cavity to the stomach. The esophagus is a tube with walls that have several layers of muscle fibers.

Inside this corridor consists of a mucous membrane, which has a useful property to greatly facilitate the passage of food through it. Thanks to the muscle fibers and mucous the food also does not damage the walls of the esophagus. The esophagus tube can expand and contract when needed by the food lump to pass into the stomach. So she pushes him.

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Stomach

It is the stomach that grinds, crushes and assimilates the food, the stomach performs the basic processes for processing the food consumed. Due to gastric juice, food is digested as qualitatively as possible, and food is split into elementary chemical compounds.

Externally, the stomach is like a sac, which is enlarged or diminished by the functional elasticity of the walls from which it consists. The capacity of the stomach can have a very large capacity. About two kilograms of the food we eat are placed in the stomach. At the very end of the stomach there is a special valve called the sphincter. It protects against premature entry into the 12-colon of food waste.

The first layer of the stomach

The stomach has three main layers. The first layer is internal, it is called the "mucous membrane" of the stomach. This first shell consists of the gastric glands. From the inside, the walls of the stomach are entirely covered with epithelial cells. Both the epithelial cells and the walls of the stomach are very different in structure and perform completely different roles.

Some of them are capable of secreting hydrochloric acid with enzymes of digestion, which secrete gastric juice. Some of the other cells secrete a mucus that envelops the stomach walls and protects them from damage.

The mucosa has a submucosa base. It is created by the type of track that is podstelen under the glands and cells of the epithelium. This foundation is permeated by many, many small blood vessels, nerves that make it possible to provide the stomach with blood, nerve cells - to transmit the necessary impulses. For example, painful.

The second layer of the stomach

This second layer is muscle. They also have a stomach. The muscles of the stomach are its thin shell. It is folded in half or even three times in layers, like puff pastry. The shell of the stomach helps to grind food, making it a gruel. Just like a mixer. Mixing with gastric juice, the food is effectively dissolved and then absorbed by the walls of the stomach.

The third layer of the stomach

And, finally, the serous membrane of the stomach is its third layer. It is created in the form of a thin tissue, which lining the abdominal cavity from the inside. And not only her, but also internal organs, giving them the opportunity to be dynamic, active, mobile.

What happens in the stomach during digestion?

When the food enters the stomach, it is moistened with gastric juice and helps it to dissolve. What is gastric juice? This liquid is viscous and dense, it is produced by the glands of the gastric mucosa. It is difficult to describe the composition of gastric juice, it includes many components. The most important components are digestive enzymes and hydrochloric acid. Of course, hydrochloric acid is a rather poisonous and burning substance that can dissolve many products. Therefore, the walls of the stomach would dissolve due to the action of hydrochloric acid, if they were not protected by mucus. But digestive enzymes help the acid dissolve foods more efficiently. These are chemically active substances.

For example, Renin is able to make cottage cheese from milk. Lipase is a substance that breaks down fats. But these enzymes do not have many functions, but they do it thoroughly. The enzyme pepsin is active in the stomach more - in composition it supplements hydrochloric acid, can split in common with it proteins taken from plant and animal foods. As a result, simpler chemical compounds - amino acids and peptides - are obtained.

When the sphincter of the stomach relaxes, the food that is already ready for the next stage of processing, in the form of gruel, enters further into the lower regions of the digestive tract. And then the remnants of the products, called chyme, continue to be digested further, but already in the intestines.

Intestines

The work of the intestine is also quite intense, and it is aimed at digesting and pushing food. The bowel performs quite a few roles, and therefore it is arranged as a complex natural construction. The intestine has several sections, conditioned anatomically. These are primarily its departments, such as the jejunum, the caecum, the duodenum, the transverse, the ascending, the subordinate gut, the colon, the sigmoid and finally the rectum. In the lower part of the intestine is located the anus. Through it outward feces come out.

How does the intestine work?

He, like the stomach and esophagus, shrinks and thus pushes the food to his lower section, which ends with the anus. These abdominal contractions are called peristalsis. And the role of the intestine in pushing feces is called a motor, in other words - it is the motility of the intestine. Heard such a term? Outwardly, the intestine resembles a pipeline through which food remains.

The intestine also has walls according to the example of the stomach. And they, too, look like sheets placed on top of each other - muscle layers. This makes the intestinal walls elastic, flexible. These walls are the mucous membrane, serous and muscular layers.

When food in the form of a liquid slurry passes through the intestine, at the same time it is split by intestinal juice into amino acids and other compounds that have the simplest structure. In this form, food is easily absorbed by the elastic and strong walls of the intestine. These substances are carried by blood and feed the body with the necessary elements that give energy.

Pay attention: the food is digested and absorbed, and also in the form of fecal masses passes into the anus through different parts of the intestine.

Duodenum

This very useful part of the intestine has a length of almost 25 centimeters. The duodenum performs a noble role - it controls the work of the stomach. He is located next to her, which is very convenient for their interaction.

The duodenum regulates the release of hydrochloric acid from the stomach for food processing and also controls its motor and excretory functions.

When hydrochloric acid becomes very high (increased acidity), it becomes dangerous for the condition of the gastric mucosa - it can begin to digest itself, which also quite hurts. Therefore, the duodenum stops this process (gastric acid secretion), transmitting the corresponding signal through the receptors. Simultaneously, the lower parts of the intestine receive a command about that. That now the food will begin to move towards them - down from the stomach.

From the duodenum for the splitting of food comes also bile, which facilitates the process of digestion. Then all elements of food - fat, carbohydrates, and proteins can be digested.

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Small intestine

It is very long - from 4 meters to 7 meters. The small intestine follows, like a girlfriend, behind the duodenum. The composition of the small intestine includes two more areas of the intestine - the ileum and the jejunum. They play important roles in digestion processes. When food reaches these parts of the intestine, the food there is chemically treated by different chemicals, and then begins to be absorbed by the walls of the intestine. In particular, those substances that are beneficial to the body are absorbed.

Details of the operation of the small intestine

In these areas of the intestine - the ileum and jejunum - food is absorbed very original - not by walls, but next to them. This process of absorption is called parietal. This role is performed by special agents - enterocytes. So called mucous cells, which refers to the small intestine. These cells are capable of secreting substances that perfectly perform the role of splitting glucose, amino acids and fatty acids, of which food consists.

And then the mucous membrane immediately absorbs these processed substances. But they are absorbed into different parts of the body. Blood sucks glucose and amino acids, and capillaries - suck in fatty acids. And then these elements of food in a liquid form move further - to the liver.

The small intestine is so important to the body that its elimination during surgery leads to death. What can not be said about the stomach, after the removal of a part of which the person lives on.

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Colon

What is not digested in the small intestine, goes further into the large intestine. This area of the intestine is called so because it is really thick compared to other parts of the intestine - some of its areas have a diameter of up to 7 centimeters. In length the large intestine is also quite large - 1-1.5 meters. The role of the large intestine is rather prosaic, but it is very useful for the whole organism. This area of the intestine is designed to create masses of feces from undigested parts of food and push them to the anus, down.

The mucosa of the colon secretes special goblet cells that have the property of secreting mucus. It helps the feces better and easier to pass through the colon and protects from damage and wounds of its wall. The large intestine makes it possible to remove harmful toxins from the body and enrich the blood with water.

With the help of bacteria in the large intestine, the food is processed further, now special bacteria are involved in this process. These are intestinal bacteria, designed specifically for processing food with the help of enzymes that they secrete.

This is E. Coli, lactobacilli, which are so familiar to us in advertising yoghurts, as well as bifidobacteria. The more diverse the intestinal microflora will be, the healthier it will be and the better it will be able to fulfill its roles. If you destroy the intestinal microflora with dysbiotic or anti-inflammatory drugs, various antibiotics, the process of digestion and assimilation of food will go much worse.

This condition is called a dysbiosis due to the destruction of most of the beneficial bacteria. Then in the intestine the fungi and microbes prevail, but was it the task of healthy food processing?

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