The stomach often digests food, but why it doesn t digest itself

She didn't dare to betray her master. Ha ha.

Because the stomach is protected by the gastric mucosa, it will digest the food that enters the stomach well, but will not digest the stomach itself.

This is due to the fact that there are certain defenses inside, and there will also be a gastric mucosa to protect the stomach, so it will not digest itself.

Because the stomach secretes a kind of gastric acid, which can digest the food we eat well.

The gastric wall can be roughly divided into five layers, from top to bottom, it is the mucosal layer, the mucosal layer, the mucus layer, the muscle layer and the serous layer, the mucosal layer is composed of epithelial cells, mucus cells, parietal cells, master cells, etc., what we call gastric acid is mainly secreted by parietal cells, so it will not corrode the function of stomach and gastric acid.

Stomach acid is made up of hydrochloric acid, which is less corrosive than other acids. Moreover, the concentration of gastric acid in the human body is low, which belongs to dilute acid, and the corrosion of dilute acid on objects is weak;

On the other hand, under normal circumstances, the proteins on the gastric mucosa have a certain resistance to gastric acid and cannot be digested by gastric acid, so they will not cause harm to people!

The stomach has a strong digestive function and relies on hydrochloric acid, pepsin, and mucus in the stomach. Hydrochloric acid is a very corrosive acid that kills bacteria when food enters the stomach. The concentration of hydrochloric acid in the stomach is high, which is enough to dissolve the metal zinc.

Pepsin breaks down proteins in food. Mucus wraps around food, lubricating and protecting the gastric mucosa from food-induced mechanical damage. The hydrochloric acid, pepsin, and mucus in the stomach combine to digest almost any food.

Since the stomach is so digestive, why can't it digest itself? This question was asked more than 100 years ago, and there has never been a complete answer. Some scientists believe that

The stomach cannot digest itself because there is a special substance in the gastric mucosa or gastric juice that resists the action of hydrochloric acid and pepsin. Scientists believe that: first, after the gastric wall secretes hydrochloric acid, hydrochloric acid will not flow backward and will not corrode the gastric wall because it is blocked by the epithelial cells on the mucosal surface.

In the event that the epithelial cells are destroyed, the mucosa secretes mucus, which has a certain buffering effect on hydrochloric acid and also prevents the hydrochloric acid that adheres to the surface of the gastric mucosa from entering the interior. The gastric mucosa also has the ability to "lose the pawn and protect the car", which allows the epithelial cells to constantly metabolize and renew, prevent pepsin from adsorbing on the mucosa, and achieve the purpose of protecting the stomach wall. In addition, the glycoproteins in the mucus, some of which contain a lot of sugar and have a large molecular weight, can inhibit the activity of pepsin.

Secondly, the human gastric mucosa cells are about 500,000 cells per minute, and they can all be renewed within three days, so that the strong regeneration ability can make up for the temporary damage caused by digestive juices to the stomach wall.

So, under normal conditions, the stomach cannot digest itself on its own. If there is too much stomach acid produced in the stomach, or if you take medicine on an empty stomach, the stomach wall is damaged, and the stomach begins to digest itself, and diseases such as gastric ulcers will occur.

In fact, while digesting food, gastric juice also has a certain damaging effect on the stomach wall, that is, causing the death of some cells.

However, due to the strong regenerative capacity of the stomach, this damage is only temporary, and the stomach recovers quickly. According to the research data of Professor Deben of the Department of Medicine of the University of Michigan in the United States, the surface of the stomach can produce about 500,000 new cells every minute. In other words, it only takes three days to regenerate a new stomach.

However, because gastric juice can dissolve the tissue of the stomach within a few hours, it is not enough to fully compensate for the loss caused by the new cells produced. Therefore, you have to have other skills.

The second function of the stomach is that the stomach wall is covered with a thick layer of epithelial cells called the gastric mucosa. It is in direct contact with gastric juices, so that corrosive gastric juices cannot penetrate into the lining of the stomach. We know that if too much acid is produced in the stomach, it can lead to stomach ulcers.

Due to its special protective effect, the gastric mucosa is protected from or only mild acid erosion.

The stomach can secrete a mucus substance, its viscosity is very large, it covers the inner surface of the stomach, protecting the surface of the stomach from hard food damage, because this mucous substance is weakly alkaline, it can prevent gastric acid from digesting and corroding the gastric mucosa itself, therefore, it will not be digested by itself.

Gastric acid has a bactericidal effect, and it is difficult for bacteria in food and drinking water to break through the first line of acid defense, and most of them are wiped out in the stomach, and gastric acid can also initially digest protein, so that the protein in meat, eggs, milk, cereals, beans, etc. in food is denatured and easily digested.