The digestive system, also called digestive or gastrointestinal (SGI) is one of the main systems of the human body and is responsible for the treatment of food and the absorption of nutrients, allowing the body to function properly. This system consists of several bodies, which act together to fulfill the following main functions:
Therefore, SGI is responsible for regulating metabolism and the immune system, in order to maintain the proper functioning of the organism.
- The digestive system consists of organs that allow the conduction of ingested food or beverages and.
- Along the way.
- The absorption of nutrients essential for the proper functioning of the organism.
- This system extends from the mouth to the anus.
- With its constituent organs:.
In addition to organs, the digestive system is composed of several enzymes that ensure the correct digestion of food, being the main:
Much of the nutrients cannot be absorbed in their natural shape because of their size or because they are not soluble, so the digestive system is responsible for the transformation of these large particles into smaller soluble particles that can be rapidly absorbed, which is mainly due to the production of various digestive enzymes.
The digestive process begins with food or beverage ingestion and ends with the release of faeces.The digestion of carbohydrates begins in the mouth, although digestion is minimal, while the digestion of proteins and fats begins in the stomach.Most digestion of carbohydrates, proteins and fats takes place in the early part of the small intestine.
The digestion time of food varies depending on the total volume and characteristics of the food consumed, and can last up to 12 hours for each meal, for example.
In the mouth, the teeth grind and crush the food consumed into smaller particles and the formed food cake is moistened with saliva, in addition the release of a digestive enzyme, salivary amylase or ptialine, which initiates the digestion of starch that constitutes carbohydrates.The digestion of starch in the mouth by the action of amylase is minimal and its activity is inhibited in the stomach due to the presence of acidic substances.
The cake passes through the pharynx, under voluntary control, and the esophagus, under involuntary control, reaching the stomach, where it mixes with gastric secretions.
In the stomach, the secretions produced are rich in hydrochloric acid and enzymes and are mixed with food; in the presence of food in the stomach, pepsin, which is one of the enzymes present in the stomach, is secreted in its inactive form (pepsinogen).and converted into pepsin by the action of hydrochloric acid. This enzyme plays a fundamental role in the process of digestion of proteins, changing their shape and size. In addition to the production of pepsin, there is also the production, to a lesser extent, of lipase, which is an enzyme responsible for the initial breakdown of lipids.
Gastric secretions are also important for increasing intestinal availability and absorption of vitamin B12, calcium, iron and zinc.
After treatment of food by the stomach, the bolus is released in small amounts into the small intestine depending on the contractions of the stomach.For liquid meals, gastric emptying lasts about 1 to 2 hours, while for solid meals, it lasts approximately.about 2 to 3 hours and varies depending on the total volume and characteristics of the food consumed.
The small intestine is the main organ of digestion and absorption of food and nutrients and is divided into three parts: duodenum, jejunum and ileon.In the initial part of the small intestine, digestion and absorption of most of the food consumed occurs due to the stimulation of enzyme production by the small intestine, pancreas and gallbladder.
Bile is secreted by the liver and gallbladder and facilitates the digestion and absorption of lipids, cholesterol and fat-soluble vitamins.The pancreas is responsible for the secretion of enzymes capable of digesting all major nutrients.Small intestine enzymes reduce low molecular weight carbohydrates and medium and large peptides, as well as triglycerides that degrade into free fatty acids and monoglycerols.
Most of the digestive process is completed in the duodenum and upper yeyuno, and the absorption of most nutrients is almost completely completed when the material reaches half the yeyuno.The entry of partially digested foods stimulates the release of several hormones and therefore enzymes and liquids that interfere with gastrointestinal motility and satiety.
Ao longo do intestino delgado quase todos os macronutrientes, vitaminas, minerais, oligoelementos e líquidos são absorvidos antes de chegar ao cólon. O cólon e o reto absorvem a maior parte do fluido restante vindo do intestino delgado. O cólon absorve eletrólitos e uma pequena quantidade de nutrientes restantes.
The remaining fibers, resistant starches, sugar and amino acids are fermented by the brush edge of the colon, resulting in short-chain fatty acids and gases. Short-chain fatty acids help maintain normal mucous function, release a small amount of energy from some of the residual carbohydrates and amino acids, and facilitate salt and water absorption.
The intestinal content takes 3 to 8 hours to reach the ileocecal valve, which is used to limit the amount of intestinal matter that passes from the small intestine to the colon and prevents its return.
Several factors can prevent digestion from working properly, which has consequences on the health of the person, some of the factors that can affect digestion are:
If you notice symptoms related to the gastrointestinal system, such as excess gas, heartburn, swollen abdominal sensation, constipation, or diarrhea, for example, it is important to see the gastroenterologist for tests to identify the cause of symptoms and start the best treatment..