People's digestion process of food.

I think what this question wants to express is how food is digested and absorbed, not only digestion but also absorption. Light digestion can't be absorbed, of course, there is no absorption without digestion, so these two aspects are actually one. But in the case of disease, there may be digestive problems, so there is nothing to absorb. Digestion may be normal, but there is a problem with absorption. Similarly, the human body can't get the energy it needs. If it is poorly absorbed for a long time, its physical quality will decline, which will affect digestion. So digestion and absorption are integrated and influence each other.

How is food digested and absorbed? Simply put, the ingested food begins to be digested in the mouth, that is, the food is ground and mixed together by chewing the teeth and stirring the tongue. In this process, amylase in saliva can decompose starchy food into maltose, which is the first step of food digestion. If this step is not done well, it will affect the next digestion of the stomach and increase the burden on the stomach.

After food is digested in the mouth, it enters the stomach through the esophagus. The stomach is a very important digestive organ. Here, the stomach grinds food and mixes it with the digestive juice of the stomach to form chyme, and then continues to descend, but there is a process of emptying.

The stomach goes down to the small intestine, and the small intestine is mainly not digested, but absorbed. When it passes through the duodenum, it is mixed with important digestive enzymes, such as protease, amylase and lipase in bile and pancreatic juice. Food is finally decomposed into sugars, amino acids, glycerol and fatty acids that can be absorbed by human body through the action of various enzymes in digestive juice, which is beneficial to be absorbed by small intestine, including water and inorganic salts. After absorption, it enters the blood. Unabsorbed or unabsorbable residues eventually form "waste" and feces, which are excreted through the rectum and anus.