Case Study: Not long ago, I saw this patient in the outpatient clinic. A male, 44 years old, came to the clinic and told me that he had chronic gastritis. He asked me to prescribe some good medicine for him. It turned out that when he was on a business trip, he had eaten possibly unclean food in a restaurant and experienced nausea, vomiting, stomach pain, diarrhea and other symptoms. This was thought to be the end of the disease, but I didn’t expect to see bloating, belching, acid reflux, loss of appetite, and recently vomiting when eating for a month, so I couldn’t stand it and went to the hospital for an examination. After gastroscopy, it was found to be “gastric sinus cancer”. When the symptoms appeared, he thought it was a minor gastrointestinal disease, so it was not a big deal, and he never underwent any examination. For such cases, there are countless clinical cases and there are many people. If people can fully understand the human gastrointestinal tract, and have some common sense health care, how many gastrointestinal diseases will be avoided! The secret of the gastrointestinal tract The stomach and intestines are the main part of the human digestive system, located in the abdominal cavity of the body. The stomach is like a large elastic pocket, and the intestines are like a curved, extremely unsmooth water pipe on the inside. In daily life, people eat grains and cereals, the gastrointestinal tract, as an important structure to accommodate and digest food, is often in contact with a variety of food and chemical substances, and is highly susceptible to damage and disease; due to improper living, weather changes and life stress, and other factors, gastrointestinal tract problems will inevitably occur. These problems are caused by structural or functional lesions of the gastrointestinal tract. The gastrointestinal tract is the most diseased system in the human body, and the diseases it suffers from are the most common in clinical practice. However, according to the survey, most patients, even those who have suffered from this disease for many years, have only a general understanding of their disease. In order to protect the gastrointestinal tract or to promote recovery from gastrointestinal diseases, it is necessary to understand the structure, function and diseases of the gastrointestinal tract. The basic function of the gastrointestinal tract The basic function of the digestive system is to help the body take in food, digest and absorb it into the energy that the body needs to support all the activities of the body. Food passes through the mouth for rough processing and enters the stomach. Peristalsis of the stomach mixes the food with gastric juices and further grinds the food into a porridge-like substance, known as surimi, which is sent into the intestine. It enters the small intestine first, and various digestive enzymes in the small intestine break down the starch, fat and protein in the food into small molecules such as glucose, amino acids, glycerol and fatty acids that can be easily absorbed by the body, and then processed by the liver to become its own substance in the body for the body’s needs; the residues that are not absorbed or not needed pass through the large intestine and are expelled through the anus. The completion of the digestive and absorption functions depends on the coordinated movement of various digestive organs and the adequate secretion of various digestive enzymes. The motor function of the digestive tract turns the large pieces of food into small food particles and mixes them with digestive juices; the smaller food particles are pushed forward, so that the small food particles are in full contact with the mucous membrane of the intestine to complete the absorption process. The food residues that cannot be absorbed are excreted to complete the function of defecation and remove the coarse and fine. Any factor that affects the motor function of the digestive tract can cause gastrointestinal dysmotility disorders. The digestion and decomposition of starch, fat and protein in the gastrointestinal tract mainly rely on hydrolytic enzymes secreted by the pancreas and gastrointestinal glands, bile secreted by the liver and enzymatic reactions involving the intestinal flora; the absorption of digested nutrients must be completed by the intestinal mucosal epithelial cells with intact structure and function. Intestinal epithelial mucosal absorption insufficiency, congenital or acquired digestive enzyme deficiency, intestinal mucosal inflammatory and neoplastic diseases, bacterial overgrowth in the small intestine can make the bile salt decomposition lose its role in digesting fat, for example, after intestinal resection, the loss of a large amount of mucosal absorption area is the main cause of digestive malabsorption. Changes in hormone levels in the body, gastrointestinal neuroendocrine dysfunction and nervous system dysfunction often tend to cause irritable bowel syndrome, functional dyspepsia, etc.