Sequence of digestion. How long does it take for food to be digested and what is the most favorable combination of foods. Digestive department - small intestine

Digestion- This is the process of chemical and mechanical processing of food, during which it is digested and absorbed by the cells of the body. Digestive pigments process incoming food and break it down into complex and simple food components. First, proteins, fats and carbohydrates are formed in the body, which in turn become amino acids, glycerol and fatty acids, monosaccharides.

The components are absorbed into the blood and tissues, contributing to the further synthesis of complex organic substances necessary for the proper functioning of the body. Digestive processes important for the body for energy purposes. Through the digestion process, calories are extracted from food, which improves performance. internal organs, muscles, central nervous system. The digestive system is complex mechanism, which involves the human oral cavity, stomach and intestines. If the products are not digested correctly, and minerals will remain unchanged, it will not benefit the body. U healthy person All stages of the digestion process last for 24 – 36 hours. Let's study the physiology and features of the digestive process to understand how it works human body.

To understand what digestion is, it is necessary to consider the structure and functions digestive system.

It consists of organs and departments:

• oral cavity and salivary glands;
• pharynx;
• esophagus;
• stomach;
• small intestine;
• colon;
• liver;
• pancreas.

The listed organs are structurally interconnected and represent a kind of tube, 7–9 meters long. But the organs are laid out so compactly that with the help of loops and bends they are located from oral cavity to the anus.

Interesting! Failures in the digestive system lead to various diseases. To ensure proper digestion, avoid eating rational nutrition, fatty foods, strict diets. Also, the organs are adversely affected by poor ecology, regular stress, alcohol and smoking.

The main function of the digestive process is to digest food and gradually process it in the body to form nutrients absorbed into the lymph and blood.

But besides this, digestion performs a number of other important tasks:

• motor or motor is responsible for grinding food, mixing with the secretions of the digestive glands and further movement through the gastrointestinal tract;
• secretory ensures the breakdown of nutritional components into mucous membranes, electrolytes, monomers and final metabolic products;
• absorption promotes the movement of nutrients from the tract cavity into the blood and lymph;
• protective consists of creating barriers using the mucous membrane;
• excretory removes toxic substances and foreign bodies from the body;
• endocrine produces biologically active substances to regulate digestive functions;
• Vitamin-forming ensures the production of vitamins B and K.

Digestive functions include sensory, motor, secretory and absorption. Among non-digestive tasks, scientists distinguish protective, metabolic, excretory and endocrine.

Features of the digestion process in the oral cavity

Stages of digestion in humans in the oral cavity, where the grinding of food for further processing begins - important processes. Products interact with saliva, microorganisms and enzymes, after which the taste of food appears and starchy substances are broken down into sugars. The processing process involves teeth and tongue. During coordinated swallowing, the uvula and palate are involved. They prevent food from entering the epiglottis and nasal cavity. The body analyzes incoming food, softens and grinds it. After this, it enters the stomach through the esophagus.

Digestive processes in the stomach

The stomach is located in the human body in the left hypochondrium under the diaphragm and is protected by three membranes: external, muscular and internal. The main function of the stomach is to digest food due to the abundant shunting of blood vessels and arteries by capillaries. This is the most wide part digestive tract, which can increase in size for suction large quantity food. During the processing of food in the stomach, the walls and muscles contract, after which it mixes with gastric juice. The process of chemical and mechanical treatment in the stomach lasts for 3 to 5 hours. Food is affected by hydrochloric acid, which is contained in gastric juice and pepsin.

Following the logical flow of the digestion process, proteins are processed into amino acids and low molecular weight peptides. Carbohydrates in the stomach stop being digested, so amylases lose their activity in an acidic environment. In the stomach cavity, due to hydrochloric acid, proteins swell and also provide a bactericidal effect. The peculiarity of the gastric digestion process is that foods rich in carbohydrates are processed briefly and after 2 hours they move on to the next process. Proteins and fats remain in the compartment for up to 8 – 10 hours.

How does digestion occur in the small intestine?

Partially digested food along with gastric juice in small portions moves to the small intestine. More happening here important cycles digestion. Intestinal juice comprises alkaline environment due to the intake of bile, secretions of the intestinal walls and under gastric juice. The digestion process in the intestines may slow down due to a lack of lactase, which hydrolyzes milk sugar. More than 20 enzymes are consumed in the small intestine as a result of the digestion process. The work of the small intestine depends on the uninterrupted functioning of three sections that smoothly transform into each other: the duodenum, jejunum and ileum.

During digestion, the duodenum receives bile formed in the liver. Due to the compounds of bile and pancreatic juice, proteins and polypeptides are broken down into simple particles: elastase, aminopeptidase, trypsin, carboxypeptidase and chymotrypsin. They are absorbed into the intestines.

Liver functions

It should be noted invaluable role the liver, which produces bile during the digestion process. The work of the small intestine would not be complete without bile, as it helps emulsify fats, activate lipases and absorb triglycerides into the stomach. Bile stimulates perilstatics, enhances the absorption of proteins and carbohydrates, increases hydrolysis and promotes the inactivation of pepsin. Bile plays an important role in the absorption and dissolution of fats and fat-soluble vitamins. If there is not enough bile in the body or it is secreted into the intestines, then the digestive processes are disrupted, and fats are released into the intestines. initial form when stool is released.

Importance of the Gallbladder

IN gallbladder In a healthy person, reserves of bile are deposited, which the body uses when processing a large volume. The need for bile disappears after the duodenum is empty. But the liver's work does not stop when food is eliminated. It produces bile, storing it in the gallbladder so that it does not spoil and is stored until the need for it arises again.

If the gallbladder is removed from the body for some reason, its absence is easily tolerated. Bile is stored in the bile ducts and from there is easily and continuously sent to duodenum regardless of the fact of eating. Therefore, after surgery, you need to eat often and in small portions so that there is enough bile to process it. This is due to the fact that there is no more space to store leftovers, which means that the reserve stock is extremely small.

Features of the large intestine

The remains of undigested food enter the large intestine. They stay in it for 10–15 hours. During this period, water absorption and microbial metabolization of nutrients occur. Thanks to the microflora of the large intestine, dietary fiber, which is classified as indigestible biochemical components, is destroyed in this section.

Among them are:

• wax,
• resin,
• gum,
• fiber,
• lignin,
• hemicellulose.

Feces are formed in the large intestine. They consist of residues that have not been digested during digestion, mucus, microbes and dead cells of the mucous membrane.

Hormones that affect digestion

In addition to the main sections of the gastrointestinal tract, the quality and speed of the digestion process are influenced by biologically active substances.

As we see, the process of digestion in the human body is a complex system, without which human life is impossible. Proper absorption of food contributes to the quality of the body. Each organ that makes up the gastrointestinal tract plays an important role. To maintain health, it is necessary to adhere to the principles of rational nutrition and exclude bad habits. Then the mechanisms will work like clockwork.

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It’s probably good to have some idea about the structure of our digestive system and what happens to food “inside”

It’s probably good to have some idea about the structure of our digestive system and what happens to food “inside”.

A person who knows how to cook deliciously, but does not know what fate awaits his dishes after they are eaten, is likened to a car enthusiast who has learned the rules of the road and learned to “turn the steering wheel,” but knows nothing about the structure of the car.

Go to long journey with such knowledge it is risky, even if the car is quite reliable. There are all sorts of surprises along the way.

Let us consider the most general structure of the “digestive machine”.

Digestion process in the human body

So let's take a look at the diagram.

We took a bite of something edible.

TEETH

We bit off with our teeth (1) and continue to chew with them. Even purely physical grinding plays a huge role - food must enter the stomach in the form of gruel; in pieces it is digested tens and even hundreds of times worse. However, those who doubt the role of teeth can try to eat something without biting or grinding food with them.

TONGUE AND SALIVA

When chewing, saliva is also soaked in, secreted by three pairs of large salivary glands (3) and many small ones. Normally, 0.5 to 2 liters of saliva are produced per day. Its enzymes mainly break down starch!

With proper chewing, a homogeneous liquid mass is formed, requiring minimal effort for further digestion.

Besides chemical exposure on food, saliva has bactericidal properties. Even in between meals, it always moistens the oral cavity, protects the mucous membrane from drying out and promotes its disinfection.

It is no coincidence that minor scratches When there are cuts, the first natural movement is to lick the wound. Of course, saliva as a disinfectant is inferior in reliability to peroxide or iodine, but it is always at hand (that is, in the mouth).

Finally, our tongue (2) accurately determines whether it is tasty or tasteless, sweet or bitter, salty or sour.

These signals serve as an indication of how much and what juices are needed for digestion.

ESOPHAGUS

Chewed food enters the esophagus through the pharynx (4). Swallowing is quite difficult process, it involves many muscles, and to a certain extent it happens reflexively.

The esophagus is a four-layer tube 22-30 cm long. IN calm state The esophagus has a gap in the form of a gap, but what is eaten and drunk does not fall down, but moves forward due to wave-like contractions of its walls. All this time, salivary digestion continues actively.

STOMACH

Rest digestive organs located in the stomach. They are separated from chest diaphragm (5) – the main respiratory muscle. Through a special opening in the diaphragm, the esophagus enters the abdominal cavity and passes into the stomach (6).

This hollow organ is shaped like a retort. There are several folds on its inner mucous surface. The volume of a completely empty stomach is about 50 ml. When eating, it stretches and can hold quite a lot - up to 3-4 liters.

So, swallowed food is in the stomach. Further transformations are determined primarily by its composition and quantity. Glucose, alcohol, salts and excess water can be immediately absorbed - depending on the concentration and combination with other products. The bulk of what is eaten is exposed to gastric juice. This juice contains hydrochloric acid, a number of enzymes and mucus. It is secreted by special glands in the gastric mucosa, of which there are about 35 million.

Moreover, the composition of the juice changes every time: Each food has its own juice. It is interesting that the stomach seems to know in advance what work it has to do, and sometimes secretes the necessary juice long before eating - at the mere sight or smell of food. This was proven by academician I. P. Pavlov in his famous experiments with dogs. And in humans, juice is released even with a distinct thought about food.

Fruits, curdled milk and other light food require very little juice of low acidity and with a small amount of enzymes. Meat, especially spicy seasonings, causes a copious release of very strong juice. The relatively weak, but extremely enzyme-rich juice is produced for bread.

In total, an average of 2-2.5 liters of gastric juice is released per day. Empty stomach periodically decreases. This is familiar to everyone from the sensations of “hunger cramps”. What you eat stops motor skills for some time. This is an important fact. After all, each portion of food envelops the inner surface of the stomach and is located in the form of a cone, embedded in the previous one. Gastric juice acts mainly on the surface layers in contact with the mucous membrane. Still inside for a long time salivary enzymes work.

Enzymes- These are substances of protein nature that ensure the occurrence of any reaction. The main enzyme in gastric juice is pepsin, which is responsible for the breakdown of proteins.

DUODENUM

As food portions located near the walls of the stomach are digested, they move towards the exit from it - to the pylorus.

Thanks to the motor function of the stomach, which has resumed by this time, that is, its periodic contractions, the food is thoroughly mixed.

As a result an almost homogeneous semi-digested gruel enters the duodenum (11). The pylorus of the stomach “guards” the entrance to the duodenum. This is a muscular valve that allows food masses to pass in only one direction.

The duodenum belongs to the small intestine. In fact, the entire digestive tract, from the pharynx to the anus, is one tube with various thickenings (even as large as the stomach), many bends, loops, and several sphincters (valves). But individual parts of this tube are distinguished both anatomically and according to the functions performed in digestion. Thus, the small intestine is considered to consist of the duodenum (11), jejunum (12) and ileum (13).

The duodenum is the thickest, but its length is only 25-30 cm. Its inner surface is covered with many villi, and in the submucosal layer there are small glands. Their secretion promotes the further breakdown of proteins and carbohydrates.

A common opening opens into the cavity of the duodenum. bile duct and the main pancreatic duct.

LIVER

The bile duct supplies bile produced by the largest gland in the body, the liver (7). The liver produces up to 1 liter of bile per day- quite an impressive amount. Bile consists of water, fatty acids, cholesterol and inorganic substances.

Bile secretion begins within 5-10 minutes after starting a meal and ends when the last portion of food leaves the stomach.

Bile completely stops the action of gastric juice, due to which gastric digestion changes to intestinal.

She also emulsifies fats– forms an emulsion with them, repeatedly increasing the surface of contact of fat particles with the enzymes acting on them.

GALL BLADDER

Its task is to improve the absorption of fat breakdown products and other nutrients - amino acids, vitamins, promote the movement of food masses and prevent their rotting. Bile reserves are stored in the gallbladder (8).

Its lower part, adjacent to the pylorus, contracts most actively. Its capacity is about 40 ml, but the bile in it is concentrated, thickening 3-5 times compared to liver bile.

If necessary, it enters through the cystic duct, which connects to the hepatic duct. The common bile duct (9) is formed and delivers bile to the duodenum.

PANCREAS

The pancreatic duct also exits here (10). It is the second largest gland in humans. Its length reaches 15-22 cm, weight - 60-100 grams.

Strictly speaking, the pancreas consists of two glands - exocrine, which produces up to 500-700 ml of pancreatic juice per day, and endocrine, which produces hormones.

Difference between these two types of glands lies in the fact that the secretion of the exocrine glands (exocrine glands) is released into the external environment, in in this case into the cavity of the duodenum, and those produced by endocrine (i.e. internal secretion) substances called hormones by glands, enter the blood or lymph.

Pancreatic juice contains a whole complex of enzymes that break down all food compounds - proteins, fats, and carbohydrates. This juice is released with every “hungry” spasm of the stomach, and its continuous flow begins a few minutes after the start of a meal. The composition of the juice varies depending on the nature of the food.

Pancreatic hormones- insulin, glucagon, etc. regulate carbohydrate and fat metabolism. Insulin, for example, stops the breakdown of glycogen (animal starch) in the liver and switches body cells to feeding primarily on glucose. This reduces blood sugar levels.

But let's return to food transformations. In the duodenum it mixes with bile and pancreatic juice.

Bile stops the action of gastric enzymes and provides proper work pancreatic juice. Proteins, fats and carbohydrates undergo further breakdown. Excess water, mineral salts, vitamins and fully digested substances are absorbed through the intestinal walls.

INTESTINES

Curving sharply, the duodenum passes into the jejunum (12), 2-2.5 m long. The latter, in turn, connects with the ileum (13), which is 2.5-3.5 m long. The total length of the small intestine is therefore 5-6 m. Its suction capacity increases many times due to the presence of transverse folds, the number of which reaches 600-650. In addition, the inner surface of the intestine is lined with numerous villi. Their coordinated movements ensure the movement of food masses, and nutrients are absorbed through them.

Previously, it was believed that intestinal absorption was a purely mechanical process. That is, it was assumed that nutrients are broken down into elementary “building blocks” in the intestinal cavity, and then these “building blocks” penetrate into the blood through the intestinal wall.

But it turned out that in the intestine food compounds are not completely “disassembled”, but final cleavage occurs only near the walls of intestinal cells. This process was called membrane or wall

What is it? Nutrient components, already fairly crushed in the intestine under the influence of pancreatic juice and bile, penetrate between the villi of intestinal cells. Moreover, the villi form such a dense border that the surface of the intestine is inaccessible for large molecules, and especially bacteria.

Intestinal cells secrete numerous enzymes into this sterile zone, and the fragments of nutrients are divided into elementary components - amino acids, fatty acids, monosaccharides, which are absorbed. Both breakdown and absorption occur in a very limited space and are often combined into one complex interrelated process.

One way or another, over five meters of the small intestine, food is completely digested and the resulting substances enter the blood.

But they do not enter the general bloodstream. If this happened, the person could die after the first meal.

All blood from the stomach and intestines (small and large) is collected in the portal vein and sent to the liver. After all, food not only provides useful compounds; when it breaks down, many by-products are formed.

You also need to add toxins here., secreted by intestinal microflora, and many medicinal substances and poisons present in products (especially in modern ecology). And purely nutritional components should not immediately enter the general bloodstream, otherwise their concentration would exceed all permissible limits.

The liver saves the situation. It is not for nothing that it is called the main chemical laboratory of the body. Here, the disinfection of harmful compounds and the regulation of protein, fat and carbohydrate metabolism. All these substances can be synthesized and broken down in the liver- as needed, ensuring the constancy of our internal environment.

The intensity of its work can be judged by the fact that with its own weight of 1.5 kg, the liver consumes approximately a seventh of the total energy produced by the body. About one and a half liters of blood passes through the liver in a minute, and up to 20% can be in its vessels total number human blood. But let's follow the path of food to the end.

From the ileum through a special valve that prevents backflow, undigested remains fall into colon. Its upholstered length is from 1.5 to 2 meters. Anatomically, it is divided into the cecum (15) with the appendix (16), the ascending colon (14), the transverse colon (17), the descending colon (18), sigmoid colon(19) and straight line (20).

In the colon, water absorption is completed and feces are formed. For this purpose, intestinal cells secrete special mucus. The colon is home to a myriad of microorganisms. About a third of the excreted feces consists of bacteria. This is not to say that this is bad.

After all, a kind of symbiosis between the owner and his “tenants” is normally established.

Microflora feeds on waste and supplies vitamins, some enzymes, amino acids and others necessary substances. In addition, the constant presence of microbes maintains the functioning of the immune system, preventing it from dozing. And the “permanent residents” themselves do not allow the introduction of strangers, often pathogenic ones.

But such a picture in rainbow colors only happens when proper nutrition. Unnatural, refined foods, excess food and incorrect combinations change the composition of the microflora. Putrefactive bacteria begin to predominate, and instead of vitamins, a person receives poisons. All kinds of medications, especially antibiotics, also hit the microflora hard.

But one way or another, fecal masses move thanks to the wave-like movements of the colon - peristalsis - and reach the rectum. At its exit, for safety reasons, there are two sphincters - internal and external, which close anus, opening only during defecation.

With a mixed diet, on average, about 4 kg of food mass passes from the small intestine to the large intestine per day, but only 150-250 g of feces are produced.

But vegetarians produce much more feces, because their food contains a lot of ballast substances. But the intestines work perfectly, the most friendly microflora is established, and most toxic products do not even reach the liver, being absorbed by fiber, pectin and other fibers.

This concludes our tour of the digestive system. But it should be noted that its role is by no means limited to digestion. In our body, everything is interconnected and interdependent both on the physical and energy planes.

More recently, for example, it has been established that the intestines are the most powerful apparatus for the production of hormones. Moreover, in terms of the volume of synthesized substances, it is comparable (!) with all the others endocrine glands, taken together. published

Every living organism, be it a bacterium, a reptile or a human, has adapted to life throughout its development largely due to the ability to absorb nutrients from environment. What are the features of food digestion in humans and animals, what are the principles of separate nutrition based on? You will learn about this from our publication.

For digestion various types food needs different times.

IN at different ages The functioning of the human digestive tract has its own characteristics, which is most clearly expressed when comparing infants, older children and adults. The work of the digestive system begins in the baby in the womb. In the second half of intrauterine development, the fetus begins to absorb the so-called amniotic fluid with the nutrients present in it, which are absorbed into the blood in the stomach and intestines, and the secretory cells of the pancreas and stomach already begin to produce a small amount of enzymes.

In a newborn baby, all digestive organs are configured to absorb mother's milk. The salivary glands are still poorly developed, and active saliva production begins only by 4-5 months of life, but even at this time its volume is only 10% of that in an adult. The enzymatic activity of saliva is low, but it is sufficient for milk casein to be well absorbed.

Infants have a short esophagus and a horizontally located stomach with poorly developed sections, which explains the phenomenon of regurgitation after feeding. In addition, young children have fewer glands in the stomach than an adult, and the acidity of the digestive secretion is lower. The digestive enzyme pepsin in infants is capable of processing only milk protein. For digestion mother's milk a baby needs about 2-3 hours, and a cow - up to 4 hours, which is why the latter is absorbed worse.

By the age of seven, the number of glands in the stomach increases, and the volume of the stomach increases to 1 liter. In children under the age of 10-12 years, intensive absorption of nutrients occurs in the stomach, while in adults this process mostly occurs in the small intestine. The acidity of gastric juice corresponding to an adult is achieved by the age of 15 due to an increase in the production of hydrochloric acid. The activity and concentration of digestive enzymes is highest in the period from 20 to 40 years, then it decreases. In men, the concentration of hydrochloric acid is higher than in women, but after 75-80 years this figure levels out between the sexes. In old age, both the activity of pancreatic secretions and the intensity of absorption of digested food decrease.

Digestion time for different foods

Let us give the time it takes to digest various foods in the stomach of an adult. Knowing it, you can competently build your daily menu and prevent intestinal blockage. The data is summarized in the table below.

In terms of speed, food is digested in this order: carbohydrates, proteins, fats. Raw animal proteins are processed much faster than cooked ones. The longer it takes heat treatment, those it's getting worse the process of digestion, which is why a soft-boiled egg is digested faster than a hard-boiled one. This table will help you in correctly compiling your menu. For example, potatoes are healthier to eat with lean fish, chicken meat with lentil porridge, etc. In addition, if you adhere to the rule that you cannot eat until your stomach is empty of food, you can lose extra pounds without strict diets and restore normal functioning of the gastrointestinal tract.

Principles of separate power supply

The ideal option for the stomach and the body as a whole is to eat foods with the same digestion time at one meal, and each next appointment should be carried out after complete absorption of the previous portion. An inconsistent diet containing dishes with many ingredients is not considered optimal and leads to cluttering of the intestines and increased decay processes in it, leading to the accumulation of toxins.

Having eaten food with a certain digestion time, you must wait until this process is completed completely and the stomach and intestines are empty. During this time, the food will have time to go through a full decomposition cycle. Only after this is it allowed to consume foods that are digested slowly, and vice versa. If you do not follow the sequence of consuming foods with at different times digestion, then the fruits are boiled and raw vegetables, starchy and protein foods begin to ferment together. In this case, gases, acids and even alcohol molecules are released, causing indigestion and clogging.

The principles of separate nutrition are based on eating only compatible foods in one serving, and you must wait at least 2 hours between meals. The exception is fruits, after which you can eat other food within 20-30 minutes.

An important rule is that you must first eat liquid food, and avoid drinking drinks during and after meals. You need to chew food thoroughly, until it reaches a consistency close to liquid. Remember that the fewer types of food you mix, the better it is digested, and the less prone you will be to overeating.

Features of digestion in animals

The process of digestion and assimilation of food occurs differently in different animals, let's see this using the example of rabbits, birds, dogs and hamsters.

Rabbits are animals that need a large amount of fiber, and they can eat up to 30 times per day, while young animals are more voracious, for example, small month-old rabbits can eat up to 55 times per day. The structure of their gastrointestinal tract is also very interesting, since the cecum is 7-9 times larger in volume than the stomach. This feature allows you to recycle great amount plant fibers, since such a large appendix of rabbits contains microorganisms that decompose cellulose. Rabbits have high acidity of gastric secretions, and their production occurs constantly, even at night, and not just during meals. Another interesting feature is caprophagy - this is when rabbits eat their night feces, which differs from their daytime feces. Thanks to this phenomenon, the animal body receives more vitamins Group B. Time complete passage feed through the rabbit's gastrointestinal tract is up to 48 hours.

Birds are endowed with a two-chamber stomach, which is divided into two sections. Each performs its own function: the first produces gastric juice, and the second works like a millstone; it always contains a lot of small pebbles and grains of sand. In terms of time, grains take the longest to digest – 6-12 hours; insects take 30-60 minutes to process. For chicken, for example, grain can be digested for up to a day, and for sparrows - up to 6 hours.

But in ruminants, the digestive system is more complex, and the stomach consists of several chambers at once: the rumen, the mesh, the book and the stomach itself, which is called the abomasum. The rumen is the largest part, and individual species, for example, in cows, can reach incredible volumes - 110-145 liters. Digestion of food is also not complete without regurgitation, when food that has entered the rumen returns to the oral cavity for more thorough grinding. It takes up to 4-6 hours to digest the food.

What interesting things can you say about dogs? To completely process the food they eat, they need from 6 to 16 hours, depending on the type of food. These four-legged friends have a peculiarity, which is that the concentration of acid in the gastric juice will be different depending on what food you offer your pet. The secretion will be most sour when eating meat, less when eating bread. But the power of the juice due to big amount enzymes are higher when the dog eats bread, and for meat, although the acidity is the highest, there are fewer enzymes in the juice. It is also interesting that dogs produce thin saliva for bread, and thicker saliva for meat.

Animals with very sensitive digestion are everyone's favorite hamsters, which cannot be fed with just anything. For example, soy that enters the gastrointestinal tract of a hamster can cause ascites, and the acid of citrus fruits is harmful to the gastric mucosa of these animals. Persimmons can cause diarrhea in your hamster, sweet foods often lead to diabetes, and salty foods impair kidney function. Vegetables and not very sweet fruits, raw nuts and corn, beans, water porridge and even baby food. Interestingly, hamsters’ teeth lack a protective layer of enamel, this is another reason why animals should not be given sweets. The hamster's stomach accepts raw apples, pears and carrots well. Also digestive enzymes the animal copes with protein foods, and every three to four days the animal can be fed chicken egg whites, low-fat boiled fish or beef without salt. It takes 3-4 hours for the food to be absorbed in the hamster’s digestive system.

This is interesting

The process of digesting food begins before it enters the stomach, since the salivary and digestive glands are activated when you are hungry or feel the aroma delicious dish or see him. This phenomenon is based on conditioned reflexes.

The human salivary glands produce more than 1.5 liters of saliva per day. Incredibly, the average person consumes up to half a ton of food per year. The total surface area of ​​the small intestine is 250 m2.

The main percentage of the hormone responsible for joy and high spirits is produced in the stomach, and it is called serotonin. Digestive juices are unable to digest chewing gum, therefore, when passing through the stomach and intestines, it remains unchanged, and can cause blockage of the intestinal lumen.

Video about separate meals from the Malakhov+ program

The digestive system daily provides the human body with the substances and energy necessary for life.

This process begins in the oral cavity, where food is moistened with saliva, crushed and mixed. Here the initial enzymatic breakdown of starch by amylase and maltase, which are part of saliva, occurs. The mechanical effect of food on the receptors located in the mouth is of great importance. Their stimulation generates impulses that go to the brain, which in turn activates all parts of the digestive system. Absorption of substances from the oral cavity into the blood does not occur.

From the mouth, food passes into the pharynx, and from there through the esophagus into the stomach. The main processes occurring in the stomach:

neutralization of food with hydrochloric acid produced in the stomach;
the breakdown of proteins and fats by pepsin and lipase, respectively, into simpler substances;
digestion of carbohydrates continues weakly (by salivary amylase inside the bolus);
absorption of glucose, alcohol and a small part of water into the blood;

The next stage of digestion occurs in the small intestine, which consists of three sections (duodenum (12 pcs), jejunum and ileum)

In 12PC, the ducts of two glands open: the pancreas and the liver.
The pancreas synthesizes and secretes pancreatic juice, which contains the main enzymes necessary for the complete digestion of substances entering the duodenum. Proteins are digested into amino acids, fats into fatty acids and glycerol, and carbohydrates into glucose, fructose, and galactose.

The liver produces bile, the functions of which are varied:
activates pancreatic juice enzymes and neutralizes the effect of pepsin;
facilitates the absorption of fats by emulsifying them;
activates the small intestine, facilitating the movement of food into lower sections Gastrointestinal tract;
has a bacteria-killing effect;

Thus, chyme - the so-called food bolus that enters the duodenum from the stomach - undergoes basic chemical processing in the small intestine. The main point of digestion is absorption useful substances- happens right here.
Undigested chyme in the small intestine enters the final section of the digestive system - the large intestine. The following processes take place here:
digestion of remaining polymers (fats, carbohydrates, proteins);
due to presence in the large intestine beneficial bacteria fiber is broken down - a substance that regulates the normal functioning of the gastrointestinal tract;
vitamins of groups B, D, K, E and some other useful substances are synthesized;
absorption of most of the water, salts, amino acids, fatty acids into the blood

The remains of undigested food, passing through the large intestine, form feces. The final stage of digestion is the act of defecation.

To maintain his life, a person must eat food. Food products contain all the substances necessary for life: water, mineral salts and organic compounds. Proteins, fats and carbohydrates are synthesized by plants from inorganic substances using solar energy. Animals build their bodies from nutrients of plant or animal origin.

Nutrients supplied to the body through food are construction material and at the same time a source of energy. During the breakdown and oxidation of proteins, fats and carbohydrates, a different but constant amount of energy is released for each substance, characterizing their energy value.

Digestion

Once in the body, food products undergo mechanical changes - they are crushed, wetted, split into simpler compounds, dissolved in water and absorbed. The set of processes as a result of which nutrients from the environment pass into the blood is called digestion.

Play a huge role in the digestion process enzymes- biologically active protein substances, which catalyze (accelerate) chemical reactions. During digestion processes, they catalyze reactions of hydrolytic breakdown of nutrients, but do not themselves change.

Main properties of enzymes:

• specificity of action - each enzyme breaks down nutrients only certain group(proteins, fats or carbohydrates) and does not break down others;
• act only in a certain chemical environment - some in alkaline, others in acidic;
• enzymes are most active at body temperature, and at a temperature of 70–100ºС they are destroyed;
• a small amount of enzyme can break down a large mass of organic matter.

Digestive organs

The alimentary canal is a tube that runs throughout the body. The canal wall consists of three layers: outer, middle and inner.

Outer layer (serosa) is formed by connective tissue that separates the digestive tube from surrounding tissues and organs.

Middle layer(muscular membrane) in upper sections the digestive tube (oral cavity, pharynx, upper part of the esophagus) is striated, and in the lower parts it is smooth muscle tissue. Most often, the muscles are located in two layers - circular and longitudinal. Thanks to the contraction of the muscular membrane, food moves through the digestive canal.

Inner layer(mucosa) is lined with epithelium. It contains numerous glands that secrete mucus and digestive juices. In addition to small glands, there are large glands (salivary, liver, pancreas) lying outside alimentary canal and communicating with them through their channels. The following sections are distinguished in the digestive canal: oral cavity, pharynx, esophagus, stomach, small and large intestines.

Digestion in the mouth

Oral cavity- the initial section of the digestive tract. From above it is limited by solid and soft palate, from below by the diaphragm of the mouth, and from the front and sides - by the teeth and gums.

Three pairs of ducts open into the oral cavity salivary glands: parotid, sublingual and submandibular. In addition to these, there is a mass of small mucous salivary glands scattered throughout the oral cavity. The secretion of the salivary glands - saliva - moistens food and participates in its chemical changes. Saliva contains only two enzymes - amylase (ptialin) and maltase, which digest carbohydrates. But since food does not remain in the oral cavity for long, the breakdown of carbohydrates does not have time to complete. Saliva also contains mucin (mucus substance) and lysozyme, which has bactericidal properties. The composition and quantity of saliva may vary depending on physical properties food. During the day, a person secretes from 600 to 150 ml of saliva.

In the oral cavity, an adult has 32 teeth, 16 in each jaw. They grab food, bite it off and chew it.

Teeth consist of a special substance dentin, which is a modification bone tissue and having greater strength. The outside of the teeth is covered with enamel. Inside the tooth there is a cavity filled with loose connective tissue in which nerves and blood vessels.

Most of the oral cavity is occupied tongue, which is a muscular organ covered with mucous membrane. It is distinguished by the top, root, body and back, on which taste buds are located. The tongue is the organ of taste and speech. With its help, food is mixed during chewing and pushed through when swallowing.

Food prepared in the oral cavity is swallowed. Swallowing is a complex movement that involves the muscles of the tongue and pharynx. During swallowing, the soft palate rises and blocks the food from entering the nasal cavity. At this time, the epiglottis closes the entrance to the larynx. The food bolus gets into throat- upper part of the digestive canal. It is a tube, the inner surface of which is lined with mucous membrane. Through the pharynx, food enters the esophagus.

Esophagus- a tube about 25 cm long, which is a direct continuation of the pharynx. No food changes occur in the esophagus, since digestive juices are not secreted in it. It serves to carry food into the stomach. The movement of the food bolus through the pharynx and esophagus occurs as a result of contraction of the muscles of these sections.

Digestion in the stomach

Stomach- the most expanded section of the digestive tube with a capacity of up to three liters. The size and shape of the stomach changes depending on the amount of food taken and the degree of contraction of its walls. At the point where the esophagus flows into the stomach and where the stomach passes into the small intestine, there are sphincters (squeezers) that regulate the movement of food.

The mucous membrane of the stomach forms longitudinal folds and contains a large number of glands (up to 30 million). The glands consist of three types cells: main (producing enzymes of gastric juice), parietal (secreting hydrochloric acid) and accessory (secreting mucus).

Contractions of the stomach walls mix food with juice, which promotes better digestion. Several enzymes are involved in the digestion of food in the stomach. The main one is pepsin. It breaks down complex proteins into simpler ones, which are further processed in the intestines. Pepsin acts only in an acidic environment, which is created by hydrochloric acid in gastric juice. Hydrochloric acid plays a major role in the disinfection of stomach contents. Other gastric juice enzymes (chymosin and lipase) are able to digest milk protein and fats. Chymosin curdles milk, so it stays in the stomach longer and undergoes digestion. Lipase, present in small quantities in the stomach, breaks down only the emulsified milk fat. The action of this enzyme in the stomach of an adult is weakly expressed. There are no enzymes that act on carbohydrates in gastric juice. however, a significant portion of the food's starch continues to be digested in the stomach by salivary amylase. The mucus secreted by the glands of the stomach plays an important role in protecting the mucous membrane from mechanical and chemical damage and from the digestive action of pepsin. The glands of the stomach secrete juice only during digestion. In this case, the nature of juice secretion depends on chemical composition consumed food. After 3-4 hours of processing in the stomach, the food gruel enters the small intestine in small portions.

Small intestine

Small intestine It is the longest part of the digestive tube, reaching 6–7 meters in an adult. It consists of the duodenum, jejunum and ileum.

The excretory ducts of two large digestive glands - the pancreas and liver - open into the initial section of the small intestine - the duodenum. Here the most intensive digestion of food gruel occurs, which is exposed to the action of three digestive juices: pancreatic, bile and intestinal.

Pancreas located behind the stomach. It distinguishes between the apex, body and tail. The apex of the gland is surrounded in a horseshoe shape by the duodenum, and the tail is adjacent to the spleen.

Gland cells produce pancreatic juice (pancreatic). It contains enzymes that act on proteins, fats and carbohydrates. The enzyme trypsin breaks down proteins into amino acids, but is active only in the presence of the intestinal enzyme enterokinase. Lipase breaks down fats into glycerol and fatty acids. Its activity increases sharply under the influence of bile produced in the liver and entering the duodenum. Under the influence of amylase and maltose in pancreatic juice, most food carbohydrates are broken down into glucose. All pancreatic juice enzymes are active only in an alkaline environment.

In the small intestine, food gruel is exposed not only to chemical, but also machining. Thanks to the pendulum-like movements of the intestine (alternate lengthening and shortening), it mixes with digestive juices and liquefies. Peristaltic movements of the intestines cause contents to move towards the large intestine.

Liver- the largest digestive gland in our body (up to 1.5 kg). It lies under the diaphragm, occupying the right hypochondrium. The gallbladder is located on the lower surface of the liver. The liver consists of glandular cells, forming lobules. There are layers between the lobules connective tissue, in which nerves, lymphatic and blood vessels and small bile ducts pass.

Bile, produced by the liver, plays a large role in the digestion process. It does not break down nutrients, but prepares fats for digestion and absorption. Under its action, fats break up into small drops suspended in liquid, i.e. turn into an emulsion. In this form they are easier to digest. In addition, bile actively influences absorption processes in the small intestine, enhances intestinal motility and the secretion of pancreatic juice. Despite the fact that bile is produced continuously in the liver, it enters the intestines only when eating. Between periods of digestion, bile is collected in the gallbladder. By portal vein Venous blood flows into the liver from the entire digestive canal, pancreas and spleen. Toxic substances, entering the blood from the gastrointestinal tract, are neutralized here and then excreted in the urine. In this way, the liver carries out its protective (barrier) function. The liver is involved in the synthesis of a number of important substances for the body, such as glycogen, vitamin A, and influences the process of hematopoiesis, the metabolism of proteins, fats, and carbohydrates.

Nutrient Absorption

So that the amino acids formed as a result of the breakdown simple sugars, fatty acids and glycerol have been used by the body, they must be absorbed. These substances are practically not absorbed in the oral cavity and esophagus. Water, glucose and salts are absorbed in the stomach in small quantities; in the large intestines - water and some salts. The main processes of nutrient absorption occur in the small intestine, which is quite well adapted to carry out this function. During suction active role plays the mucous membrane of the small intestine. It has a large number of villi and microvilli, which increase the absorption surface of the intestine. The walls of the villi contain smooth muscle fibers, and inside them there are blood and lymphatic vessels.

Villi take part in the absorption of nutrients. By contracting, they promote the outflow of blood and lymph, rich in nutrients. When the villi relax, fluid from the intestinal cavity again enters their vessels. The products of the breakdown of proteins and carbohydrates are absorbed directly into the blood, and the bulk of digested fats are absorbed into the lymph.

Colon

Colon has a length of up to 1.5 meters. Its diameter is 2–3 times larger than the thin one. It contains undigested food residues, mainly plant foods, the fiber of which is not destroyed by enzymes of the digestive tract. There are a lot of different bacteria in the large intestine, some of which play an important role in the body. Cellulose bacteria break down fiber and thereby improve absorption plant food. There are bacteria that synthesize vitamin K, which is necessary for the normal functioning of the blood coagulation system. Thanks to this, a person does not need to take vitamin K from external environment. In addition to the bacterial breakdown of fiber in the large intestine, a large amount of water is absorbed, which enters there along with liquid food and digestive juices, which ends with the absorption of nutrients and the formation of feces. The latter pass into the rectum, and from there are excreted through anal hole. The opening and closing of the anal sphincter occurs reflexively. This reflex is under the control of the cerebral cortex and can be voluntarily delayed for some time.

The entire process of digestion with animal and mixed food in humans lasts about 1–2 days, of which more than half of the time is spent moving food through the large intestines. Feces accumulate in the rectum, as a result of irritation of the sensory nerves of its mucous membrane, defecation occurs (emptying the colon).

The digestion process is a series of stages, each of which takes place in a certain part of the digestive tract under the influence of certain digestive juices secreted by the digestive glands and acting on certain nutrients.

Oral cavity- the beginning of the breakdown of carbohydrates under the action of salivary enzymes produced by the salivary glands.

Stomach- the breakdown of proteins and fats under the influence of gastric juice, the continuation of the breakdown of carbohydrates inside the food bolus under the influence of saliva.

Small intestine- completion of the breakdown of proteins, polypeptides, fats and carbohydrates under the action of enzymes of pancreatic and intestinal juices and bile. As a result of biochemical processes, complex organic substances are transformed into low-molecular substances, which, when absorbed into the blood and lymph, become a source of energy and plastic materials for the body.