The stomach generally refers to the stomach and the small and large intestine parts of the digestive system. The stomach and small intestine are the core of nutrient absorption. Almost all the nutrients the human body needs pass through the stomach and intestines. The stomach becomes the most important organ for digestion.
Systematic evolution
With the emergence of animals, the metabolic cycle of nutrition presents a new pattern different from that of plants. From the simplest single-celled animals to the most complex - humans - the process of digesting food has become complicated.
Single-celled animals digest food in the cell, to the two-layer multicellular animals, can achieve extracellular digestion, but also has the absorption function.
The emergence of triblastic animals, such as annelids, whose digestive organs have been differentiated into the foregut, midgut, and hindgut, which can crush and emulsify food and reabsorb it.
By the emergence of vertebrates, the digestive system of animals has been completely differentiated, and there have been organs such as pharynx, esophagus, stomach, large and small intestine, liver and pancreas. Nature has made man the highest end product, with the most complex and complete digestive system.
The occurrence of chronic diseases is closely related to the stomach and intestines. If you want to understand the occurrence of chronic diseases from the root, you must study the stomach. How does the food we eat every day get digested in our stomachs?
What is the process of gastrointestinal "work"? To understand these problems, we can understand the causes of chronic diseases.
Working process
On the 20th day of human embryo development, the head and tail of the gut in the embryo form the anterior and posterior intestines, and the middle part forms the midintestines. Later, the midgut disappeared, and the anterior gut formed most of the pharynx, esophagus, stomach, duodenum, jejunum and ileum.
The posterior intestine develops into a small portion of the distal ileum, cecum, appendix, colon, and rectum. The endoderm of the enteric duct develops into the epithelium of the digestive duct, various small digestive glands, liver, pancreas, thyroid, parathyroid, thymus, and respiratory epithelium.
When you get up in the morning, your gut begins to move, and waste, residue, dirt, urine and feces, hundreds of toxins are waiting to be discharged from your anus.
After the "garbage" has been emptied, it is time to eat. At this time, the intestinal tract begins the work of absorption, and the liver is ready for bile for food digestion. At this time, the salivary glands under the tongue secrete a large number of protease, lipase, detoxification enzymes and other digestive enzymes to decompose and digest food.
When these foods enter the mouth, all the food is chewed and ground through the teeth, so that the taste buds get full contact. Taste buds will pass the carbohydrates, proteins, vitamins, fats, minerals, water, non-nutrients, toxic ingredients, etc. contained in these foods to the next level of digestive organs, so that they do a good job of "reception". The food goes down the esophagus and reaches the stomach.
gullet
In the passage to the stomach - the throat, its front is the pharynx, can also directly absorb liquid nutrients.
If the food is chewed lightly enough, the pharynx can absorb some of the nutrients directly. Therefore, when eating, can not be gobbled up, so as not to miss the nutritional opportunity.
The stomach
The stomach is divided into four parts, the cardia, the fundus, the body of the stomach, and the pylorus. The functions of the stomach include absorbing food, blending food and secreting gastric juices. As well as have endocrine function, produce some hormones, promote gastrointestinal activity. The stomach of an average adult can hold 12 pounds of food. When the food you eat reaches your stomach, your stomach secretes a large amount of gastric acid that corrodes, melts, and prepares the food for absorption into the duodenum. The stomach empties food differently.
For vegetables and fruits, it is generally emptied once every 3 hours; For white meat, such as fish, chicken, about 3.5 hours to empty once; For mixed foods, empty once every 4.5 hours; For red meat, it takes longer to empty.
