"Absorption" is a process that transports digested nutrients directly from the cavity of the gastrointestinal tract into the lymph, blood and intercellular space. In physiology, this is how the ability of tissues to assimilate the molecules they need for life, which as a result of this, are modified. In this article, we will provide a definition of the term, a description of the entire process and its features.
Oral cavity
Absorption is a process that takes place throughout the entire digestive tract. At the same time, each department has its own individual characteristics. We will analyze them depending on which department this process takes place in.
For example, in the oral cavity absorption of substances occurs in small quantities for the reason that food does not stay for a long time. Only some substances are capablealmost completely absorbed in the oral cavity, quickly entering the blood cavity, bypassing the liver and intestines. For example, these are some drugs (validol, essential oils, nitroglycerin), as well as a deadly poison - potassium cyanide.
As a rule, the ability of these substances to intensive absorption is a way of their emergency introduction into the body.
Stomach
In the stomach, under the influence of enzymes and hydrochloric acid, the digestion process is enhanced.
It should be noted that certain types of nutrients must be processed longer than others. So, protein and fats are digested much longer, especially compared to carbohydrates. This is due to the fact that they secrete enzymes much later.
The stomach is, in fact, the focus of digestive activity, but at the same time, an extremely small amount of nutrients is absorbed in it. Only alcohol, large amounts of dissolved minerals and water, some glucose and amino acids can be absorbed in the stomach.
Small intestine
During absorption in the small intestine, the absorption of almost all available nutrients begins. This is mainly due to its structure, since it is this organ that is maximally adapted to the suction function. With the absorption of nutrients, the course of the process is directly dependent on the surface area on which it is carried out.
On one square centimeter of the small intestinecontains from two to three thousand villi. In addition, each villus has microvilli - a kind of finger-like outgrowths. They increase the suction surface. Enzymes are located between the villi themselves, which are also involved in the parietal process of digestion.
In this organ, absorption is a type of nutrient breakdown that is considered extremely efficient for the body. This is explained by the fact that there are many microorganisms in the intestines. Provided that cleavage would occur only in the intestinal lumen, the microorganisms would use most of the cleavage products. In this case, very little would get directly into the blood. Due to their size, micro-organisms are unable to get in between the villi.
Large intestine
Further, food enters the large intestine. This is where further absorption takes place in the intestines. At this stage, the body absorbs water, short-chain fatty acids and minerals, such as sodium, calcium, potassium, chloride. It is also here that the absorption of vitamins produced by symbiotic bacteria occurs. These are vitamin K and B vitamins.
Polyols and soluble dietary fiber are processed by bacteria, and what is formed as a result of their breakdown is sent to the large intestine.
Mechanisms
Absorption of nutrients and other important substances for our body occurs under the influence of certain processes. Different mechanisms are responsible for the absorption of different substances.
Filtration laws are responsible for the reduction of smoothmuscles, which increases blood pressure. This is a trigger mechanism for the absorption of certain substances into the blood. Diffusion ensures that part of organic molecules, s alts, and a certain amount of water enter the blood. It is worth noting that diffusion involves the arbitrary movement of substances in solution, which leads to equilibrium from concentration in volume.
Another important mechanism is osmosis. This is the name given to the movement of molecules of different substances through a semipermeable membrane that allows them to pass only in one direction. With an increase in osmotic pressure, the process of water absorption is significantly accelerated.
Finally, absorption consumes a lot of energy, especially when digesting certain substances. These include a number of amino acids, glucose, sodium ions, fatty acids. According to the results of the experiments, it was found that with the help of special poisons it is possible to completely stop or lead to a violation of absorption in the mucosa. For example, you can completely interrupt the body's supply of sodium ions, which can lead to a significant deterioration in human well-being.
Features
This process requires a significant increase in the so-called cellular respiration in the mucosa located in the small intestine.
Assimilation is also facilitated by the reduction of the villi. Each of them is covered on the outside by an epithelium, and inside there are lymphatic and blood vessels, as well as nerves. The smooth muscles located inside, during contraction, push the contents of the lymphatic vessel and capillary into larger arteries. In the intervals between muscle relaxation, smallthe vessels of the villi consume the necessary substances from the small intestine. The result is that each villus is like a powerful pump.
During one day, about ten liters of liquid are absorbed. Of these, 4/5 are digestive juices. In the human body, intestinal epithelial cells are mainly responsible for the consumption of nutrients.
Regulation of suction processes
An important function of the digestive system is the regulators located in it. This may be nervous or hormonal regulation.
In nervous regulation, the functions of the digestive system are controlled by two types of neurotransmitters. In this case, the spinal cord or brain has a third-party effect on the organs of the gastrointestinal tract. As a result, certain substances are synthesized - adrenaline and acetylcholine.
Adrenaline is responsible for relaxing muscles in individual organs, and also reduces blood flow to them. Acetylcholine at the same time stimulates the muscles in the digestive organs to intensively move food through the gastrointestinal tract. In addition, this substance encourages the pancreas and stomach to produce more digestive juices.
Of great importance is also the work of internal nerves, which form a dense network in the walls of the stomach, esophagus and intestines. When under the influence of food the walls of the organs are stretched, they are activated. The internal nerves give a large number of substances that speed up or slow down the production of juices and the movement of food.
During hormonal regulation, hormones that directly control the functioning of the stomach organs,released by mucosal cells located in the small intestine and the stomach itself. It turns out secretin, which stimulates the work of the pancreas in the production of digestive juice. Gastrin induces the stomach to produce hydrochloric acid, which is involved in the digestion of certain foods. It is also required for normal growth of the intestines and gastric mucosa.
Finally, cholecystokinin appears, which promotes the growth of the pancreas and the production of pancreatic juice enzymes. This helps release the contents of the gallbladder.
External factors
It is worth noting that the process of assimilation of nutrients is affected by a certain number of external factors. For example, stress is one of them. In many patients, digestive problems occur just against this background. The reaction of the nervous system to stress is not conducive to digestion, has a negative effect on absorption.
Some people take antacids to reduce symptoms, but these drugs reduce the absorption of certain nutrients. So some experts consider their use counterproductive.
In such a situation, the most effective method is to change the attitude to the surrounding circumstances, which a person cannot influence. Often this helps to significantly relieve heartburn and dyspepsia, restore the normal functioning of all digestive organs.
Drugs can act in both directions when interacting with nutrients. Yes, corticosteroids.reduce the absorption of vitamin D and calcium. Therefore, they are often prescribed after sports injuries in order to reduce the inflammatory process. Other drugs may have the opposite effect. Therefore, it is so important to carefully study the instructions, be sure to consult a doctor when planning to drink this or that medicine.
Influence of alcohol
Due to alcohol in the human body, there is a lack of nutrients even when their amount corresponds to the daily intake. The fact is that alcohol damages the mucous membrane when absorption occurs in the stomach and small intestine. As a result, the absorption of minerals and vitamins is significantly altered and reduced.
In addition, alcoholic beverages prevent the breakdown of nutrients by reducing the secretion of digestive enzymes. To avoid this, it is recommended to reduce the amount of alcohol consumed as much as possible.
Methods to improve suction
It is believed that the human body is able to absorb from 10 to 90 percent of the nutrients contained in food. To normalize and maximize this value, it is recommended to take care of the restoration of the digestive tract in case of any damage or disturbance.
Instead of raw vegetables and fruits, drink more juices that are already processed, which helps to facilitate the digestion process. The right combination of food, thorough chewing also plays an important role.
Nutritional concentrationsubstances
It's worth knowing that some nutrients are ways to take a leading position in the assimilation. For example, calcium stops the absorption of iron.
You also need to remember this, keep track of the combination in which you consume useful substances.
