The initial sections of the gastrointestinal tract. Common diseases of the gastrointestinal tract. What happens in the human digestive tract

Details

Knowledge of the physiology of the gastrointestinal tract is a necessary element of the foundation of medical education.

1. The main functions of the gastrointestinal tract.

2. Anatomy and physiology of the gastrointestinal tract: the location and functions of each department.

3. The main parts of the gastrointestinal tract and their function.

Oral cavity (tongue, teeth, three pairs of salivary glands) and pharynx (formation of a food bolus + BEGINNING OF CARBOHYDRATE DIGESTION)
Esophagus (skeletal muscle + smooth muscle - transportation of the food bolus)
Stomach (accumulative function and digestion)
Fundal part
antrum
pyloric part (limits the speed of advancement of the food bolus or chyme)
Small intestine (functions: digestion, transport, absorption)
Large intestine (transportation, absorption, reabsorption, formation and excretion of undigested food debris)

4. Oral cavity (tongue, teeth, three pairs of salivary glands) and pharynx (formation of food bolus + BEGINNING OF CARBOHYDRATE DIGESTION).

5. The secret of the salivary glands.

6. The main functions of saliva.

1. Wetting the crushed food and preparing the food bolus for swallowing
2. Initial hydrolysis of carbohydrates by salivary amylase
3. Neutralization of hydrochloric acid, which can be thrown from the stomach into the esophagus

7. Cellular structure of the salivary glands.

Cells are collected in clusters
Serous cells secrete the aqueous component of saliva
Mucoid cells secrete the viscous or mucous part of saliva - mucin (glycoprotein).

8. Anatomy of the salivary gland.

Acinar cells produce the enzyme amylase; Parietal cells produce bicarbonate;

9. Composition of saliva.
Alpha-amylase, mucin, bicorbanate, RNA-case, DNA-ase, peroxidase, kallikrein, etc. - volume of 1.5 liters per day.
The pH value - in the absence of food or thought about it - (6 - 7); during meals - (7-8)

10. Chemistry of digestion: carbohydrates.

food carbohydrates: vegetable and animal origin - starch, cellulose, amylopectin, glycogen, sucrose, lactose, glucose, fructose

Enzymes that carry out the hydrolysis of carbohydrates:
Amylase- saliva and pancreatic juice and enzymes of parietal digestion.

11. Autonomic nervous system.

Consists of sympathetic and parasympathetic divisions. The figure shows the effects that autonomous NS has on digestion.

12. Regulation of amylase secretion.

13. Swallowing reflex.

1 phase - arbitrary
Phase 2 - fast involuntary, lasting less than 1 s, occurs with reflex inhibition of breathing
Phase 3 - slow involuntary, lasts 5-10 s, is carried out by peristaltic movements of the esophagus wall and pressure drop

14. The mechanism of food bolus advancement through the esophagus.

15. Promotion of food through the stomach, electrical activity and contraction of the muscles of the stomach, evacuation of chyme.

16. Anatomical structure of the gastric wall.

17. Transport systems of parental cells providing HCl secretion and its regulation.

18. Activation of the pepsinogen proenzyme and its conversion into an active form - pepsin is carried out by partial proteolysis in the presence of H+ ions.

19. Cells of the stomach: their secret, function and localization.

20. Main functions of the gastric phase.

Cumulative
Enzymatic hydrolysis of proteins and partially fats, formation of chyme
HCl - parietal cells (protective role - neutralization of bacteria & denaturation of proteins)
Lipase–chief cells
Pepsinogen-chief cells
Protecting the mucosa by isolating bicorbanate and mucin.

21. Chemistry of digestion: proteins.

Squirrels(average intake -0.5-0.7 g/day/kg body weight --> enzymatic hydrolysis --> amino acids
Enzymes:

endopeptidase (hydrolysis of the peptide bond between amino acids)
exopeptidase (hydrolysis of amino acids with N(aminopeptidase) or C-terminus (carboxypeptidase)

22. Peptic ulcer.

The pathogenesis of peptic ulcer is multifactorial. and is primarily due mismatch between mucosal protective factors and mucosal damage factors.

Damaging factors:

hydrochloric acid
decreased blood flow
decrease in the secretion of bicarbonates and mucus (the action of NSAIDs)
Helicobacter pylori (gram-negative bacterium that destroys the mucous membrane, releasing toxic substances and causing inflammation)
Nicotine (increases production of hydrochloric acid)

Protective factors:

formation of a mucous lining (protective effect)
bicarbonates (secreted by epithelial cells)
blood flow (causes homeostasis of the gastric wall)
prostaglandin E (stimulates bicarbonate and mucus production)

23. Factors determining the rate of passage of chyme from the stomach into the duodenum.

24. The main parts of the intestine and their function.

Small intestine (digestion + absorption)
Duodenum (25cm)
Jejunum
Ileum
Pancreas
Liver
Large intestine (passes 1.5L of chyme per day - absorption and absorption)
Colon (faecal production)
Rectum
Anus (voluntarily controlled sphincter - excretion of undigested residues)

25. Histology of the intestinal wall.

The wall of the small intestine, like the stomach, consists of 4 layers:

Mucous membrane (inner layer)
Epithelial layer (contains the gastric glands, in the case of the intestine, the brush border and crypts)
Connective tissue layer (lamina propria)
Muscular layer (inner -muscularis mucosae)
Submucosal layer (middle)
Muscle layer (outer layer)
Serous membrane

26. Functional significance of mucus secretion for the gastrointestinal tract.

Produced by specialized exocrine cells
Mucous cells of the stomach
Goblet intestinal cells
Viscous secret
glycoproteins = mucin
Function - formation of a protective layer of the mucosa - lubricating, sliding effects
Mucus secretion is controlled by the nervous system, neuropeptides of the enteric system, cytokines of immune cells
With inflammation of the gastrointestinal tract - mucus secretion increases

27. Types of peristaltic contractions of the gastrointestinal tract.

Type of contractile activity of smooth muscles

Tonic - minutes, hours
phasic - seconds

Types of gastrointestinal wall contractions

Peristaltic propulsion - the movement of chyme through the gastrointestinal tract
Segmental - mixing

28. Enteral nervous system.

29. Reflexes in the gastrointestinal tract.

30. Regulation of digestion: autonomic and enteral nervous systems.

Regulation of the nervous and endocrine systems, local control
Vegetative reflex

Can be excited both inside and outside the gastrointestinal tract
Reflexes from other systems - either painful or emotional

Enteral reflex

Submucosal ganglia & myenteric ganglia
contraction, secretion

Gastrointestinal proteins

Act as hormones or paracrino (locally)
Gastrointestinal reflexes

31. Pancreatic secretion.

Cholecystokinin is secreted by the enteric endocrine cells of the duodenum into the blood, binds to receptors on the acinar cells of the pancreas and stimulates secretion.

HCI Stimulates the secretion of secretin, which causes the release of bicarbonate and water

32. Features of digestion in the duodenum.

Determines the rate of gastric emptying and the strength of contractions of its smooth muscles (reflex);
pH neutralization, bile secretion & enzymes;
secretion of pancreatic juice;
The movement of chyme towards the small intestine;

33. Nature and mechanism of secretion of gastrointestinal enzymes.

Enzymes are synthesized and secreted by exocrine glands (salivary, gastric and intestinal glands and pancreas).
They are of a protein nature.
Secreted by exocytosis
Formed from an inactive proenzyme
Excretion is controlled by the nervous system, hormonally and paracrinely

34. Enzymes of the gastrointestinal tract.

35. The structure of the epithelium of the small intestine (brush border).

Villi and microvilli
Lymphatic vessels
Arterial and venous vessels
Communication with the portal system of the liver
Chylomicrons (mixture of fats with cholesterol)

36. Chemistry of digestion: fats.

With food, triglycerides enter the body mainly. In a small amount - phospholipids and cholesterol.
A small amount of fat dissolved in the oil is exposed to the action of gastric lipase and absorbed in the stomach.
More fat particles require bile emulsification for enzymatic degradation, transport and absorption.
Enzymes: lipases, colipases & phospholipases
Triglycerides --> Monoglycerides & Free Fatty Acids
Free cholesterol consumed with food is absorbed directly

37. Secretion and production of bile.

Bile is produced by hepatocytes
The components of bile are:

Bile salts (= steroids + amino acids). Detergents capable of reacting with water and lipids to form water-soluble fatty particles
Bile pigments (result of degradation of hemoglobin)
cholesterol

Bile is concentrated and deposited in the gallbladder.
Bile is released from the gallbladder when it contracts.

38. The process of emulsification of fats and fat-soluble vitamins (A, D, E, K) with bile.

39. Intestinal phase of fat degradation and absorption.

Colipase releases bile, lipase breaks down fats, micelles are formed. Fat-soluble vitamins are absorbed.

40. Chemistry of digestion: carbohydrates.

41. Intestinal phase of degradation and absorption of carbohydrates.

Hydrolysis to simple sugars
suction / transport

Na+/glucose or galactose symport (apical membrane)
fructose is transported by GLUT5 (apical and basolateral membranes)
Transport of glucose across the basolateral membrane by the GLUT2 transporter into the capillary

42. Intestinal phase of protein degradation and absorption.

Hydrolysis to tri-dipeptides and amino acids;
Membrane transport: H+, Na+ cotransport (CAT1, CAT2 transporters) and transcytosis through the enterocyte and then into the capillary;

43. Localization of absorption and secretion sites along the gastrointestinal tract.

44. Mechanism of absorption of vitamin B12.

45. The mechanism of absorption of iron ions.

46. Cation-transport channels.

47. Exchange of ions and water in the digestive tract.

ions: H+, K+, Na+, HCO3-, Cl-
They come from the intestinal fluid into the lumen of the gastrointestinal tract through the apical and basolateral membranes of the epithelium
Water follows an osmotic gradient

48. Fluid exchange in the gastrointestinal tract: total - 9 liters, of which 5 liters from tissues and 2 liters p / os.

49. Absorption in the large intestine.

50. Secretion of ions in the large intestine.

51. Main functions of the large intestine.

Bacterial fermentation
Absorption and secretion of ions
Water reabsorption about 1.4 liters/day
Defecation reflex and excretion of fecal matter

52. General principles of absorption in the gastrointestinal tract.

In the process of digestion, the food bolus undergoes mechanical and enzymatic decomposition into macromolecules.
Small pieces of food are the object of action of bile and food enzymes.
The specific pH value for various parts of the gastrointestinal tract is characteristic.
The acidic pH is in the stomach.
Alkaline pH - in the mouth and intestines.
Absorption of nutrients is mainly in the small intestine.
Absorption of ions & water - large intestine.

Anatomy of the gastrointestinal tract is a complex of organs that ensure the vital activity of the body. The scheme of the structure of the gastrointestinal tract is the human organs sequentially located, and depicted as cavities. The hollow spaces are interconnected and form a single channel for accepting, changing the qualitative structure, and removing food. The length of the entire channel is about 8.5 - 10 meters. Each hollow (empty from the inside) organ is surrounded by shells (walls) that are identical to each other in structure.

The walls of the gastrointestinal tract

Shells of hollow channels have the following structure:

From the inside, the walls of the gastrointestinal tract are lined with epithelium - a layer of mucosal cells that are in direct contact with food. The mucosa performs three tasks:

protection from damage (physical or toxic effects);
enzymatic breakdown of nutrients, vitamins, minerals (parietal digestion, carried out in the small intestine);
the transfer of fluid into the blood (absorption).

After the mucous membrane is the submucosal layer, consisting of connective tissue. The tissue itself does not have a functional component, it contains numerous venous, lymphoid and nerve clusters.
The muscular membrane, which follows, has an uneven thickness in different areas of the gastrointestinal tract. It is endowed with the function of moving food through the digestive tube.
The outer layer of the walls is represented by the peritoneum (or serous membrane), which protects the organs from external damage.

Major organs of the gastrointestinal tract

The anatomy of the human gastrointestinal tract is an integration of the digestive tract and glands that synthesize the digestive secret.

The departments of the gastrointestinal tract include the following organs:

The initial site is the oral fissure (oral cavity).
Muscular tube in the form of a cylinder (pharynx).
Muscular canal that connects the stomach sac and the pharynx (esophagus).
Hollow food processing tank (stomach).
A thin tube about 5 meters long (small intestine). Consists of the initial section (duodenum), middle (jejunum), and lower (ileum).
The lower (final) part of the gastrointestinal tract (large intestine). It consists of: the initial sac-like department or the caecum with the process of the appendix, the colon system (ascending, transverse, descending, sigmoid) and the final department - the rectum.

All parts of the gastrointestinal tract are endowed with certain functions that make up the whole process of digestion, which is the initial one in a complex metabolic mechanism.

Oral cavity

The primary gastrointestinal tract includes:

musculoskeletal organ (lips);
mucous membrane lining the cavity (gums);
two rows of bone formations (teeth);
mobile muscular organ with a fold going to the gums (tongue);
a pharynx bounded by a hard and soft palate;
salivary glands.

Functional purposes of the department:

mechanical grinding, chemical processing and differentiation of food taste;
formation of sounds;
breath;
protection from pathogens.

The tongue and soft palate are involved in the process of swallowing.

Pharynx

It has the shape of a funnel, localized in front of the 6th and 7th cervical vertebrae. By structure, it consists of the upper, middle and lower parts (nasopharynx, oropharynx, laryngopharynx, respectively).

Connects the oral cavity with the muscular canal of the esophagus. Takes part in the processes:

breathing;
speech formation;
reflex contraction and relaxation of muscles to promote food (swallowing);

The pharynx is equipped with a mechanism of protection against external negative factors.

Esophagus

A flattened muscular canal up to 30 cm in length, consisting of the cervical, thoracic and abdominal parts, ending in a cardiac valve (sphincter). The valve closes off the stomach to prevent backflow of food and acid (into the esophagus). The main task of the body is to move food towards the stomach for its further processing (digestion).

Stomach

The scheme of the stomach includes four main zones, divided among themselves conditionally:

Cardiac (supracardial and subcardial) zone. It is located at the junction of the stomach and esophagus, equipped with a closing sphincter (valve).
Upper section or vault. It is placed on the left side under the diaphragm. It is supplied with glands that synthesize gastric juice.
Organ body. It is localized below the arch, has the largest volume of all organs of the gastrointestinal tract, is intended for temporary storage of food coming from the muscle canal, and its splitting.
The pylorus or pyloric zone. It is located at the bottom of the system, connecting the stomach and intestines through the pyloric (outlet) valve.

hydrochloric (HCl) acid;
enzymes (pepsin, gastrixin, chymosin);
protein (mucin);
enzyme with bactericidal properties (lysozyme);
mineral salts and water.

Functionally, the stomach is designed to store and process food, absorb liquids and salts.

Digestion of food occurs under the action of gastric juice and muscle contractions of the body. When the stomach is empty, juice production stops. The resulting semi-solid substance (chyme) is sent to the duodenum with the help of the vagus (vagus nerve).

Small intestine

It performs the main work on food processing (abdominal and parietal digestion), acid neutralization, as well as the function of absorption (absorption) of nutrients to deliver them to the bloodstream.

Consists of three zones:

Duodenum. Responsible for the work of the output pulp (its timely and regular reduction). It is supplied with gastric, pancreatic, intestinal juice and bile. The alkaline secret is synthesized by glands located in the walls of the organ. Under the influence of these liquids, the process of digestion of chyme occurs.
T small intestine. Smooth muscle organ involved in the digestive process. Without clear boundaries, it passes into the next zone - the ileum.
Ileum. Anatomically covered by the peritoneum on all sides, takes an active part in the breakdown of nutrients and other substances. It ends with the ileocecal sphincter that separates the large and small intestines.

The process of breaking down food is completed in the small intestine.

Colon

The lower zone of the gastrointestinal tract, endowed with the function of absorbing fluid, and the formation of excrement. The organ does not secrete juice, it produces a mucous substance for the excrement-forming process.

Divided into several zones:

Cecum. It is equipped with a process that does not play a big role in the body - the appendix.
The colon system consists of four organic zones (ascending, transverse, descending, sigmoid) that are not involved in the process of food processing. The functional purpose is the absorption of nutrients, the activation of the movement of processed products, the formation, maturation and excretion of excrement.
Rectum. The final zone of the digestive tract. Designed for the accumulation of fecal formations. The structure has a strong muscular valve (anal sphincter). The main function is the dynamic release of the intestine from accumulated excrement through the anus.

The complex structure of the human gastrointestinal tract requires careful attention. Malfunctions in the work of one of the organs inevitably lead to disturbances in the work of the entire digestive system.

The gastrointestinal tract (GIT) contains organs responsible for the mechanical and chemical processing of food. The unique structure of the gastrointestinal tract and the coordinated functioning of all its departments allow the body to extract useful components from food, absorb the necessary substances into the lymph and blood, and remove the remains through the anus.

How is the digestive system

It has a complex structure. Each organ in a healthy body functions in a certain sequence, without any failures, which guarantees high-quality food processing and a person's well-being. This is due to the characteristic structure of the elements and the functions performed.

The digestive system is represented by the following organs:

salivary glands;
liver;
gallbladder;
pancreas;
stomach and other parts of the gastrointestinal tract.

The salivary glands are located in the oral cavity. Their structure allows you to produce a certain amount of secretion necessary for the normal formation of the food bolus and its further movement. The liver is a kind of filter, it helps to release useful substances and eliminate toxins from the body. The gallbladder produces bile, which is directly involved in the process of digestion. The stomach is responsible for processing the incoming food and its further movement to the intestines. The pancreas secretes special enzymes involved in the process of splitting.

Each of the presented elements of the digestive structure performs its specific work and is responsible for the normal movement, splitting and processing of incoming products. Without the normal functioning of the digestive system, it is difficult to imagine human life.

General functions of the gastrointestinal tract and its departments

The role of each section of the gastrointestinal structure is important. Violation in the performance of one of the organs affects the entire process of digestion. Its failures, in turn, worsen the general well-being of a person.

Functions of the gastrointestinal tract

The gastrointestinal tract is divided into eight main parts with a unique structure. The passage of food is carried out in the following departments.

Oral cavity.
Throat.
Esophagus.
Stomach.
Small intestine.
Large intestine.
Rectum.
Anal opening.

All organs of the gastrointestinal tract are hollow. Consistently connecting with each other, they form a single digestive canal.

Functions of the ZhTK organs

Oral cavity and pharynx

Consider the organs of the gastrointestinal tract in detail. The highest and starting point of the gastrointestinal tract is the mouth. Its structure is represented by lips, hard and soft palate, tongue and cheeks. The oral cavity is responsible for the production of the required amount of saliva, which will allow food to be mixed mechanically and move it freely to the pharynx and esophagus. The oral cavity, due to its structure, is in close contact with the pharynx through the isthmus of the pharynx. Its inner part is covered with a mucous membrane, the surface of which is dotted with multiple ducts of the salivary glands. The soft palate is distinguished by the muscles involved in the process of swallowing.

The tongue is a mobile organ based on muscle tissue. Its leading tasks are chewing food, the process of swallowing and sucking. The tongue is characterized by the following sections: body, apex, root and back. Its upper part is represented by a mucous membrane dotted with nerve endings. Collectively, these receptors are responsible for recognizing the taste of food. The tip of the tongue determines the sweet taste, the root - bitter, the middle and lateral parts - sour. The upper part of the tongue adjoins the gum through a special bridle. Salivary glands are located on its surface.

The pharynx is represented by a 15 cm long tube that connects the oral cavity with the esophagus. It consists of three main sections: nasopharynx, oropharynx and larynx. Due to its structure, it is responsible for the process of swallowing and the further movement of food.

Esophagus and stomach

This section is the main transport route of food from the mouth to the stomach. This is a soft elastic tube, the length of which is 25 cm. A distinctive feature of the esophagus is the ability to stretch and adapt to the size of the passing food bolus. The organ then contracts and returns to its original position.

Thanks to careful chewing and a sufficient amount of saliva, the food bolus quickly moves from the esophagus to the stomach. The time of movement of food does not exceed 7 seconds. The structure of the lower end of the organ is represented by a sphincter, or constrictor. It "closes" after swallowing food, thereby preventing the acidic contents of the stomach from refluxing back into the esophagus.

The stomach is located in the upper part of the peritoneum. Its volume is 500 ml. Under the influence of excessive food intake, the stomach is able to stretch. In the normal state, the volume increases to one liter. This is an important organ of the gastrointestinal tract, which takes all the food coming from the pharynx. The special structure of the stomach allows it to produce gastric juice and additional components that are actively involved in the processing of products.

It is noteworthy that all food comes in a weak alkaline environment, and after a short period of time it adapts to an acidic one. This is due to the acidic environment of the stomach itself and its unique structure. The organ contains many enzymes, including gelatinase, amylase, and lipase. They are responsible for the breakdown of collagen, gelatin and oil tributarins.

It takes about two hours for food to break down in the stomach.

Small and large intestine

The absorption of nutrients is carried out exclusively here, in this part of the gastrointestinal tract. The small intestine is responsible for the main process of digestion. It is represented by several departments: duodenum, jejunum and ileum. All parts are in sequence. The special structure allows you to freely move the remnants of food further along the digestive tract.

Sections of the intestine

The anatomy of the large gastrointestinal tract is complex. It contains: cecum, colon, ascending colon, transverse colon, descending colon, and sigmoid colon. They are responsible for the absorption of liquid and useful components. The main function is the formation of fecal masses from the remnants of incoming food, which is provided for by the structure of the organ.

Rectum and anus

The length of this intestine is 18 cm. It is a complex closing apparatus. Its structure: the muscles of the pelvic diaphragm and the sphincter of the anus. Above this part of the gastrointestinal tract is an ampoule, it contains feces, under the weight of which the walls of the department expand. This process gives the urge to void. In the absence of pathologies and diseases of the gastrointestinal tract, the ampoule should be empty. Under the influence of provoking factors, namely unhealthy diet, it is constantly clogged, which provokes poisoning with poisons and toxins. With proper functioning of the gastrointestinal tract, feces are regularly excreted from the body through the anus.

Violations in the work of the human gastrointestinal tract lead to improper processing of food and poisoning with toxins. A moderate rhythm of life and proper nutrition will help normalize the functioning of all departments.

In the process of digestion, our body receives the substances it needs from borscht, meatballs and milk. This is the main purpose of the gastrointestinal tract - the transformation of food into small molecules for absorption into the blood.

The breakdown of complex natural substances into simpler ones in order to assimilate them by the body is the essence of the digestion process.

Oral cavity, pharynx, esophagus

- in these organs, food is pre-processed before it passes through the gastrointestinal tract.

The body begins to prepare for a meal when a person still smells food or sees a set table. At the same time, saliva is intensively secreted in the oral cavity. It acts as a lubricant during chewing and swallowing.

As soon as food enters the mouth, all the glands of the digestive tract increase their work. In the mouth, food is crushed and chewed, its solubility increases, and the surface area for the action of enzymes increases. This greatly facilitates the further processes of digestion and absorption.

For maximum grinding of food, a full set of teeth is needed - the absence of several of them cannot be compensated for by more intense or prolonged chewing. The presence of teeth is a prerequisite for the normal functioning of the gastrointestinal tract. Do not build illusions: if several teeth are missing, the digestion process is disturbed. Therefore, either insert your teeth, or cook your own dishes from well-mashed products, passed through a meat grinder.

Salivation gives food the consistency it needs to be swallowed. Saliva is formed at a rate of about 1 liter per day! It is also important for the preservation of teeth: if it is insufficient, they are affected by caries and fall out. Saliva also has a bactericidal effect. Finally, under the action of saliva, the digestion of carbohydrates begins.

The crushed lump of food is swallowed and enters the esophagus - a muscular tube 25-35 cm long. This tube has two muscular "rings" - the sphincter. One at the entrance - prevents the free passage of air into the esophagus. The other at the exit - prevents the contents of the stomach from being thrown back into the esophagus. The circular muscles of the esophagus contract, and the food bolus moves towards the stomach. When food reaches the stomach, it opens in its cardial part. And then, when filled, it “closes”.

So, food in the stomach. Its muscles contract, grind, mix the food masses so that the gastric juice saturates all the contents.

The main components of gastric juice are hydrochloric acid, mucus and enzymes. On average, about 2 liters of gastric juice are produced per day. Hydrochloric acid "dissolves" food. It also gives bactericidal properties to gastric juice. Mucus protects the inner part of the stomach from the damaging effects of hydrochloric acid and prevents it from self-digestion. Enzymes provide the digestive activity of gastric juice.

Mixed food lingers in the stomach of an adult for 3-6 hours. During this time, food undergoes chemical processing by gastric juice. The stomach is "drawn" into the process of digestion, when a person still sees food, smells it. That is, gastric juice is secreted even before food enters the stomach cavity. This portion of gastric juice has a very high acidity and activity. (That's why you shouldn't provoke your stomach with chewing gum!)

Further, the food itself, which has entered the stomach, stimulates gastric secretion. And when food passes into the intestines, the amount of gastric juice begins to decrease. Meat food is the most effective causative agent for the secretion of gastric juice. Its maximum release falls on the second hour of the digestion process. In addition, the daily consumption of meat food leads to an increase in gastric secretion to other products, increasing the acidity and digestive power of gastric juice.

When eating fatty foods, the digestive power of gastric juice is lower than that of the juice that is released when eating meat foods, but higher than when eating carbohydrate foods. And the maximum secretion of gastric juice occurs by the end of the 3rd hour.
Carbohydrate food is the weakest causative agent for the secretion of gastric juice. After you have eaten bread or a roll, the maximum of gastric juice is secreted within an hour, then its secretion decreases sharply and is kept at a low level for a long time. Therefore, we must remember that a carbohydrate diet leads to a decrease in acidity and the digestive power of gastric juice!

Most often, violations of the function of the stomach are associated with pathology of secretion. With excessive production of hydrochloric acid, peptic ulcer of the stomach and / or duodenum can develop, and insufficient production of hydrochloric acid occurs with atrophic gastritis.

Physiologists say that stress leads to an increase in the secretory activity of the gastric glands. It turns out that there is a lot of gastrointestinal juice and its activity is high, and the cells of the mucous membrane of the stomach and duodenum are weakened and not protected. This often leads to acute gastritis, ulcers, erosions. Many, being in a state of stress, felt for themselves how stress increases appetite. The body seems to be telling you: "Protect your stomach!" Therefore, being in a tense environment, activate nutrition, otherwise you can earn a stomach ulcer and other troubles in a matter of days. Briefly, this formula may look like this: “Survived stress - eat!”

Fear, longing and depression dramatically reduce the activity of the gastric glands. During this period, you should not “force” yourself with food. Some try to "eat or drink, drown out longing." But because you ate without appetite, through force, longing will not pass, but you can harm your body. Undoubtedly, if such a state does not last one hour or two, but stretches for days, then the diet should contain foods that enhance gastric secretion, which means meat is a must. If during such a period you give preference to bread and buns, that is, carbohydrates, you risk getting fat.

Pancreas

This gland belongs both to the endocrine system (produces the hormones insulin, glucagon, etc.), and to the digestive system, since it produces pancreatic juice. It enters through the excretory ducts into the duodenum. The pancreas is able to secrete 1.5 liters of secretion per day. It consists of the enzymes lipase (digests fats), trypsin (breaks down proteins) and amylase (breaks down carbohydrates).

The quantitative composition of enzymes depends on the nature of the food. In the first two hours, a sharp increase in the secretion of pancreatic juice causes protein and carbohydrate foods (meat, bread). When taking fatty foods (milk), the rise in secretion is not so sharp, more smooth. The cells of the pancreas, just like the salivary glands and the glands of the stomach, begin to separate the juice in advance: at the mere sight and smell of food.

With intense physical and mental work, suffering associated with physical or mental pain, pancreatic secretion decreases. Therefore, within an hour after eating, it is undesirable to start active work. Immediately after sleep, you should not eat a lot, especially heavy fatty foods.

Liver and biliary system

The liver affects the metabolism of proteins, fats, carbohydrates, as well as hormones and vitamins. The liver synthesizes many substances vital to the body. In addition, many harmful and toxic substances are neutralized with the help of the liver. Its main function in the process of digestion is the production and secretion of bile.

Bile enters the lumen of the duodenum. Without it, the normal process of digestion of food in the intestines is impossible. Even a slight decrease in bile secretion gives rise to putrefactive processes. Bile is produced by liver cells - hepatocytes continuously. If there is digestion, it immediately enters the bile ducts into the duodenum.

Once digestion is complete, bile is stored in the gallbladder. Here it concentrates, increasing its viscosity and specific gravity. In 24 hours, bile is concentrated 7-10 times. Hence the conclusion: prolonged fasting leads to stagnation of bile and contributes to the formation of stones in the gallbladder. In addition, during fasting, the gallbladder does not contract, which means that fasting contributes to the weakening of its muscles - atony of the gallbladder, etc.

Powerful causative agents of bile secretion are yolks, milk, meat, bread. The greatest amount of bile is formed when consuming mixed food. The bile excretes the end products of metabolism, for example, bilirubin (a breakdown product of hemoglobin), as well as medicinal substances and toxins. Bile excretion of cholesterol plays an important role in the regulation of its balance. The bile acids found in bile are essential for the digestion of fats.

The best known and most common disorder of the normal function of the biliary system is the precipitation of cholesterol to form cholesterol gallstones (cholelithiasis). Excess body weight is one of the risk factors for increasing the relative content of cholesterol in the body and, accordingly, for gallstone disease.

Small intestine

In the small intestine, the final breakdown of nutrients occurs, the absorption of the digested through the villi of the mucosa, the movement of the remaining substances further along the gastrointestinal tract, the production of hormones and immunity factors. The small intestine is 5-7 meters.

The first section of the small intestine is the duodenum. It is so named because its length in humans is approximately 12 finger diameters. The excretory ducts of the liver and pancreas open into the duodenum.

The process of digestion in the intestine begins in the cavity of the small intestine (cavitary digestion). Further splitting of the formed compounds occurs on the walls of the small intestine (membrane digestion). In this case, an important role belongs to the proper intestinal enzymes.

Intestinal juice is a product of the activity of various glands and cells of the entire mucous membrane of the small intestine. Unlike other digestive glands, they are excited and secrete their secret only in the place where the food bolus is located. The most powerful causative agent of the secretory activity of the cells of the mucous membrane of the small intestine are the products of protein digestion by gastric juice, fatty acids, and pancreatic juice.

Food that has entered the intestines moves through it due to the work of the corresponding muscles. Fear, fright, danger, anxiety, pain can cause inhibition of intestinal motility. Strong emotions and prolonged fear are accompanied by violent intestinal motility, leading to diarrhea ("nervous diarrhea").

Absorption is the main function of the gastrointestinal tract. Due to absorption, the substances necessary for the normal functioning of the body are transferred from the intestine to the internal environment of the body (blood, lymph, tissue fluid). The main part of absorption is the small intestine. Water, mineral salts, vitamins and hydrolysis products are absorbed here. Their absorption rate is exceptionally high. Within 1-2 minutes after food substrates enter the intestine, they appear in the flowing blood. Part of the liquid (about 1.5 liters) as part of the food substrate enters the large intestine, where it is almost completely absorbed.

Colon

The large intestine includes the cecum, the ascending, transverse, and descending colons, the sigmoid colon, and the rectum. Digested food in the small intestine enters the large intestine. Here, the absorption of substances necessary for the body continues. And in the lumen of the intestine, the remains of the waste products of the cells and salts of heavy metals that are unnecessary to the body are released.

Dehydrated intestinal contents accumulate in the large intestine and are removed from the body. Here the absorption of vitamins E, K and group B, synthesized by microflora, takes place. The large intestine maintains the water and mineral balance in the body. An important feature of the large intestine is its ability to take over the function of the previous sections of the intestine, if there are violations in them.

Dysmotility of the large intestine leads to constipation or diarrhea. Changes in the microflora of the colon lead to a serious illness - dysbacteriosis. The intestinal flora fills the terminal part of the ileum. Microorganisms, already well known to many by the names of various bifid-kefirs (Bifidus, Bacteroides), E. coli, lactic acid bacteria, streptococci, multiply abundantly here.

Substances secreted by bacteria break down fiber fibers that are not digested in the small intestine. The intestinal microflora supports and stimulates the production of natural immunity, protecting the human body from the introduction and reproduction of pathogenic microbes. Suppression and destruction of the normal intestinal microflora, in particular by prolonged use of antibacterial drugs, entails severe complications with the development of unnatural flora, such as yeast.

Fermentation and putrefaction processes take place in the intestines. Due to fermentation, an acidic environment is created in the intestines, which prevents putrefaction. Normal healthy microflora prevents an increase in the concentration of putrefactive bacterial decomposition products and other substances harmful to the body (indoles, skatoles, hydrogen, sulfur dioxide and methane). A balanced diet balances the processes of fermentation and decay. If the balance is disturbed, digestive disorders and intoxication of the body can occur.

The gastrointestinal tract is a complex system! Each organ is an important link in the chain of digestion and assimilation of food.

Don't put your digestive system to the test with newfangled diets, fasting, and other fables. Each person has their own metabolism. Before starting any diet, please consult your doctor.

The digestive system is daily exposed to the pathological effects of exogenous factors, so gastrointestinal diseases occur in almost everyone. It is worth noting that the digestive system includes the gastrointestinal tract, liver and pancreas. We suggest that you consider in detail the diseases of the gastrointestinal tract and understand their causes. We also superficially outline the methods for diagnosing and treating pathologies of the gastrointestinal tract.

The structure of the digestive system and the functions of each organ

The structure of the gastrointestinal tract

The gastrointestinal tract is a system for processing food and obtaining nutrients, vitamins and minerals from it, as well as removing residues. The length of the digestive tract of an adult is on average 9 meters. The gastrointestinal tract starts at the mouth and ends at the anus. Main sites: oral cavity and pharynx, esophagus, stomach, small and large intestine.

Diseases of the oral cavity are a separate issue and the dentist deals with their treatment. These include diseases of the teeth, oral mucosa, salivary glands. Of the diseases of the pharynx, tumors can most often be found, but the percentage of their detection is small.

Functions of the digestive tract

Each organ of the gastrointestinal tract performs its own function:

The esophagus is responsible for delivering the crushed food bolus to the stomach. Between the stomach and the esophagus there is a special esophageal-gastric sphincter, problems with which are the cause of diseases of the esophagus.
In the stomach, the protein fractions of food are broken down by the action of gastric juice. Inside the stomach is an acidic environment, and in other parts of the gastrointestinal tract - alkaline. Next, the food bolus moves through the sphincter into the duodenum 12.
The duodenum stimulates the active breakdown of food due to bile acids and pancreatic enzymes that enter there through the major duodenal papilla.
The remaining sections of the small intestine (jejunum and ileum) ensure the absorption of all nutrients except water.
In the large intestine, feces are formed due to the absorption of water. There is a rich microflora here, which provides the synthesis of nutrients and vitamins absorbed through the colon mucosa.

Diseases of the esophagus and stomach

The esophagus is a hollow tube that connects the mouth and stomach. His diseases are associated with pathologies of other organs, in particular, the esophageal-gastric sphincter and stomach. The esophagus also suffers from malnutrition, like other parts of the gastrointestinal tract. Fatty, fried, spicy food disrupts the function of the stomach and contributes to the reflux of acidic gastric contents into the esophagus. This pathology is called reflux or gastroesophageal reflux disease (GERD).

How does reflux from the stomach into the esophagus occur?

Interesting: Heartburn is a sign of acidic stomach contents entering the esophagus. The manifestation is a symptom of reflux esophagitis, but not an independent disease.

More than half of the population has GERD, and if left untreated with age, the disease leads to the formation of atypical areas of the epithelium on the esophageal mucosa - Barett's esophagus develops. This is a precancerous condition that, without treatment, turns into a malignant oncopathology.

Tip: So, seemingly harmless gastritis can make a person disabled. Therefore, it is worth considering, perhaps the principles of proper nutrition should still be followed?

Diseases of the stomach are known to all. This is gastritis and peptic ulcer. However, we also often do not think about their complications. Why can they be dangerous? Both of these pathologies are accompanied by a violation of the integrity of the gastric wall and sooner or later reach the choroid plexuses. When the defect affects several vessels, gastric bleeding appears. This emergency surgical pathology is manifested by the following symptoms:

Nausea, vomiting with an admixture of blood;
Weakness, cold sweat;
Black stools are the main sign of bleeding from the upper GI tract.

Important: peptic ulcer of the stomach and duodenum is dangerous for the development of perforation - rupture of the wall of a hollow organ with the release of its contents into the abdominal cavity and the development of peritonitis. This complication is treated only by open surgery.

Pathology of the small intestine

The most common pathology of the small intestine is duodenal ulcer. Much is known about this gastrointestinal problem, so we suggest that you consider the less common, but still dangerous, diseases of the small intestine.

Enteritis is an inflammation of the small intestine that develops as a result of the use of low-quality products. This is an acute disease, which in most cases has a mild course, especially if the provoking factor is eliminated. The manifestations of the disease are vomiting and diarrhea, as well as deterioration of the general condition due to intoxication. Enteritis often resolves without treatment, but cases with a prolonged course, uncontrollable vomiting and dehydration require specialized care.
Celiac disease is an intolerance to the protein gluten found in wheat, rye and barley. Given that most foods contain these substances, the life of a person with gluten-free enteropathy is difficult. The disease has no cure. The main thing is to identify and eliminate provoking factors in time. Pathology manifests itself in childhood from the moment the intolerable foods are introduced into the diet. With timely access to a pediatrician, identifying celiac disease is not difficult, and people who follow a special diet forget about their problem forever.
Crohn's disease is a chronic autoimmune disease. The disease begins with acute pain, similar to appendicitis. Due to chronic inflammation, the absorption of nutrients is impaired, which leads to general exhaustion. In addition to pain, the symptoms of Crohn's disease include diarrhea and blood in the stool, and patients can report up to 10 bowel movements per day.

Of course, the most dangerous are tumors of the small intestine. For a long time, these diseases of the gastrointestinal tract occur without symptoms. Often, specialists detect them only when the patient addresses for intestinal obstruction, which is due to the complete blockage of the intestinal lumen by a growing tumor. Therefore, if there have been cases of oncopathologies of the intestine in your family, or if you are regularly worried about constipation, followed by diarrhea and vague abdominal pain, contact a specialist for a preventive examination.

Colon diseases

It is difficult to write all diseases of the gastrointestinal tract in one article, so we will single out the most serious pathologies of the large intestine - this is ulcerative colitis, polyposis and diverticulosis.

Nonspecific ulcerative colitis refers to chronic diseases of the gastrointestinal tract that have an autoimmune nature, like Crohn's disease. Pathology is multiple ulcers on the colonic mucosa that bleed. The main symptom of the disease is diarrhea mixed with blood and mucus. The disease requires long-term hormone therapy and diet. With timely detection and proper management of the patient, ulcerative colitis is completely controlled, which allows patients to lead a normal life.

Intestinal polyposis is often asymptomatic and is detected only when cancer develops against the background of long-term polyps. Polyposis is found on colonoscopy. Often polyps are incidental findings during examination for other pathologies.

Important: Polyps are often detected in members of the same family, so if your relatives suffered from polyposis or oncopathologies of the colon, after 40 years, you should undergo preventive examinations. At a minimum, this is a fecal occult blood test, and ideally a colonoscopy.

Diverticulosis is a pathology in which multiple protrusions - diverticula - form in the intestinal wall. The disease may be asymptomatic, but with inflammation of the diverticula (diverticulitis), there is pain in the abdomen, blood in the stool, and a change in the nature of the feces. Especially dangerous complications of diverticulosis are intestinal bleeding and perforation of the colon, as well as acute or chronic intestinal obstruction. With timely treatment to the clinic, pathology is easily diagnosed and treated.

What do colonic diverticula look like?

Among other common pathologies in the large intestine, Crohn's disease can also develop. The disease, as indicated, begins in the small intestine, but without treatment spreads to the entire digestive tract.

Remember: A disease found early in its development is the easiest to treat.

Causes of digestive problems

Why do diseases of the digestive tube develop? The main reason is malnutrition. Specifically, the factors that disrupt the functioning of the gastrointestinal tract include:

Poor quality food, fast food, the use of semi-finished products;
Irregular meals, overeating;
Eating a large amount of spicy, fried, smoked foods, canned foods;
Abuse of alcohol, carbonated drinks.

Another cause of gastrointestinal diseases is the uncontrolled use of drugs. When prescribing therapy for chronic diseases, medications should be taken reasonably, if necessary, under the guise of proton pump inhibitors (Omez). Also, you should not use any medications on your own. This is especially true of non-steroidal anti-inflammatory drugs (NSAIDs), which patients often take uncontrollably for headaches. All NSAIDs increase the acidity of gastric contents, creating an aggressive flora inside the stomach, causing erosion and ulcers.

Methods for diagnosing gastrointestinal diseases

Diseases of the gastrointestinal tract have similar symptoms. Then it is important for the specialist to understand which part of the digestive tube is affected. There are diagnostic methods that allow for a targeted examination of the upper or lower gastrointestinal tract (FEGDS and colonoscopy), as well as those that are suitable for examining the entire digestive tube (radiography with contrast and capsule endoscopy).

FEGDS for examination of the mucous membrane of the esophagus, stomach and duodenum 12. The method allows to establish such diagnoses as gastroesophageal reflux disease, esophagitis, gastritis, gastric ulcer and duodenal ulcer.
Colonoscopy is used to diagnose colon pathologies. Like FEGDS, the technique allows you to take a section of the intestinal mucosa or neoplasm for histological examination.
A contrast-enhanced X-ray is performed by taking a series of images after the patient drinks a barium solution, which is completely safe. Barium gradually envelops the walls of all organs of the gastrointestinal tract, allows you to identify constrictions, diverticula, and neoplasms.
Capsule endoscopy is a modern method for diagnosing gastrointestinal diseases, which is not performed in every clinic. The bottom line is that the patient swallows a special capsule with a video camera. She moves through the intestines, recording images. As a result, the doctor receives the same data as after FEGDS and colonoscopy, but without discomfort for the patient. The method has two significant disadvantages: high cost and the impossibility of taking a biopsy.

What does a capsule for endoscopic diagnostics of the digestive tract look like?

In addition to instrumental methods for the diagnosis of diseases of the gastrointestinal tract, various tests are prescribed.