Humoral stuffing of the gastric glands. Regulation of gastric juvenoculation

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Nervous and humoral mechanisms are involved in the regulation of secretory activities of the gastric glands.

The entire process of gastric juvenoculation can be divided into three in the time of the phase in each other:
1. complexoreflexion (cefalic),
2. Gastric,
3. Intestinal.

The initial excitation of the gastric glands (the first cefalic or complex reflex phase) is due to the irritation of visual, olfactory and auditory receptors with the view and odor of food, the perception of the entire situation associated with the meal (conditionaloreflex component of the phase). The irritations of the receptors of the oral cavity, phase, in the process of its chewing and swallowing (unconditional reflector component of the phase) are enjoyed on these effects.

1.1. FacilityFlexor phase

The first component of the phase It begins with the release of gastric juice as a result of the synthesis of afferent visual, hearing and olfactory irritation in Talamus, the hypothalamus, the limbic system and the crust of large hemispheres of the brain. This creates conditions for increasing the excitability of the neurons of the digestive bulbar center and the launch of the secretory activity of the gastric glands.

Fig.9.3. Nervous regulation of the gastric glands.

The irritation of the receptors of the oral cavity, pharynx and esophagus is transmitted according to afferent fibers V, IX, X pairs of cranial nerves in the center of gastric juice in the oblong brain. From the center of impulses along the efferent fibers of the vagus nerve, they are sent to gastric glands, which leads to an additional unconditional reflector strengthening of secretion (Fig. 9.3).

Juice, released under the influence of the type and smell of food, chewing and swallowing, was called "Appetizing"or wicked. Due to its release of the stomach, it turns out to be pre-prepared for reception. The presence of this secretion phase was proved by I.P.Pavlov in a classic experiment with imaginary feeding in esophagotomy dogs.

Gastric juice, obtained in the first complex phase, has high acidity and large proteolytic activity. Secretion in this phase depends on the excitability of the food center, it is easily inhibited when exposed to various external and internal stimuli.

1.2. Gastric phase

Second - ventricular (neurogumoral) phase. On the first complex flex phase of the gastric secretion, the second - gastric (neurogumoral) is located. In the regulation of the gastric phase of secretion, the wandering nerve, local intramural reflexes take part. The release of juice in this phase is associated with the reflex response when the gastric mucosa of the stomach of mechanical and chemical stimuli (food that fell into the stomach, hydrochloric acid, distinguished with the "beast juice" dissolved in water, extractive substances of meat and vegetables, protein digestion products ), as well as stimulation of secretory cells with tissue hormones (gastrin, gastamine, bombiness).

The irritation of the gastric mucosa receptors causes the flow of afferent pulses to the neurons of the stem brain, which is accompanied by an increase in the tone of the wandering nerve nuclei and a significant increase in the stream of efferent pulses by a wandering nerve to secretory cells. The discharge of the nerve endings of acetylcholine not only stimulates the activities of the main and head cells, but also causes the excretion of gastrine G-cells of the anthral gastric department. Gastrin- the strongest of the well-known stimulants of the shepherd and to a lesser extent of the main cells. In addition, gastrin stimulates the proliferation of the cells of the mucous membrane and increases the blood flow in it. The release of gastrene is enhanced in the presence of amino acids, dipeptides, as well as with moderate stretching of the antral stomach. This causes the excitation of the sensory link of the peripheral reflex arc of the EN terral system and through the interneuries stimulates the activity of G-cells. Along with the stimulation of the shepherd, main and G-cells, the acetylcholine enhances the activity of histidydhecarboxylase ECL cells, which leads to an increase in the content of histamine in the gastric mucosa. The latter acts as a key stimulator for the production of hydrochloric acid. Histamine acts on H 2 receptors of the shepherd cells, it is necessary for the secretory activity of these cells. Histamine also has a stimulating effect on the secretion of gastric proteinases, however, the sensitivity of winter cells to it is small due to the low-density H 2 -receptors on the membrane of the main cells.

1.3. Intestinal phase

Third (intestinal) phase Gastric secretion occurs when moving food from the stomach in the intestine. The amount of gastric juice released into this phase does not exceed 10% of the total gastric secretion. Gastric secretion in the initial phase period increases, and then begins to decline.

The increase in the secret is due to a significant strengthening of the flow of afferent pulses from the mechanical and chemoreceptors of the mucous membrane of the 12-rosted intestine during the admission from the stomach of weakly acidic food and the release of gastroy G-cells of the duodenum. As the acidic chimus is proceeds and the reduction of the pH of the duodenal content below 4.0, the secretion of the gastric juice begins to be caught. Further depression of secretion is caused by the appearance in the mucous membrane of the 12rd secretinewhich is a gastrin antagonist, but at the same time enhances the synthesis of pepsinogen.

As the 12 row and increase the concentration of protein and fat hydrolysis products, the oppression of secretory activity increases under the influence of peptides isolated by gastrointestinal endocrine glands (somatostatin, va-zoactive intestinal peptide, cholescocytein, gastric inh bitor hormone, glucagon). The excitation of afferent nerve paths occurs when irritating the hemo- and sophoreceptors of the intestine by eating foods from the stomach.

Hormone enterogastrin,food in the intestinal mucosa is one of the stimulants of the gastric secretion and in the third phase. Food digestion products (especially proteins), sitting in the intestines in blood, can stimulate gastric glands by enhancing the formation of histamine and gastrin.

Stimulation of gastric secretion

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Some of the nerve impulses exciting gastric secretion, originates in the dorzal nuclei of the wandering nerve (in the oblong brain), reaches on its fibers of the enteral system, and then comes to gastric glands. Another part of the secretory signals occurs within the enteral nervous system itself.
Thus, both the central nervous system and the enteral nervous system are involved in the nervous stimulation of the gastric glands.

Reflex influences come to gastric glands on the reflex arcs of two types.
First - Long Reflex Arc - include structures by which afferent pulses are directed from the stomach mucosa to the corresponding brain centers (in the oblong brain, hypothalamus), the efferent - are sent back to the stomach of wandering nerves.
Second - short reflex arcs - ensure the implementation of reflexes within the local enteral system. Stimuli causing the occurrence of these reflexes occurs when tensile the wall of the stomach, tactile and chemical (HCI, pepsin, etc.) with the influences on the gastric mucosa receptors.

Nervous signals coming to gastric glands on reflex arcs, stimulate secretory cells and at the same time activate G-cells producing gastrin.

Gastrin is a polypeptide secreted in two forms:
"Big Gastrin"containing 34 amino acids (G-34), and
little form (G- 17), which includes 17 amino acids. The latter is more efficient.

Gastrin coming to glandular cells with blood flow, excites parietal cells and to a lesser extent - the main one. The speed of secretion of hydrochloric acid under the influence of gastrin may increase 8 times. The separated hydrochloric acid, in turn, exciting the chemoreceptors of the mucous membrane, contributes to the secretion of the gastric juice.

The activation of the vagus nerve is also accompanied by the enhancement of histididecarboxylase activity in the stomach, as a result of which the content of histamine increases in its mucous membrane. The latter directly acts on parietal glindulocytes, significantly increasing the secretion of NS1.

Thus, adhesilcholine, released on the nerve endings of the wandering nerve, gastrin and histamine have simultaneously stimulating effects on the gastric glands, determining the release of hydrochloric acid. The secretion of pepsinologists -nu is regulated by the main glindulocytes (exempted at the end of the vagus nerve and other enteral nerves), as well as the effects of hydrochloric acid. The latter is associated with the occurrence of enteral reflexes in the irritation of the National Assembly of the Gastric mucosa receptors, as well as with the release under the influence of Gastrene NS1, which has a direct impact on the main glindulocytes.

Food and gastric secretion

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Adequate causative agents of gastric secretion are substances used in food. Functional adaptations of the gastric glands to various food are expressed in various character of a secretory reaction to them of the stomach. The individual adaptation of the stomach secretory apparatus to the nature of food is due to its quality, quantity, power mode. The classic example of the adaptive reactions of the gastric glands is the studied I.P.Pavlov secretory reactions in response to meals containing predominantly carbohydrates (bread), proteins (meat), fats (milk).

Fig.9.4. Allocation of gastric and pancreas on various foods.
Gastric juice - dotted line, pancreas - solid line.

The most effective causative agent of secretion is protein food (Fig. 9.4). Proteins and their digestion products have a pronounced juice action. After receiving the meat, the rather energetic secretion of the gastric juice with a maximum on the 2nd hour is developing. Long-term meat diet leads to increased gastric secretion on all nutritional stimuli, increasing the acidity and digestive strength of the gastric juice.

Carbohydrate food (bread) is the weakest secretion pathogen. Bread is poor chemical pathogens of secretion, so after its reception, a response secretory reaction is developing with a maximum of 1st hour (the reflex compartment of the juice), and then decreases sharply and for a low level is held for a long time. With long-term finding a person on a carbohydrate mode, the acidity and the digestive force of the juice are reduced.

The effect of fats of milk on gastric secretion is carried out in two stages: brake and exciting.
This explains the fact that after meals, the maximum secretory reaction is developing only by the end of the 3rd hour. As a result of the long-term nutrition nutrition, gastric secretion on food irritants due to the second half of the secretory period occurs due to the second half of the secretory period. The digesting force of the juice when used in fats in food is lower compared to juice released during meat mode, but higher than when powered by carbohydrate food.

The amount of separation of gastric juice, its acidity, proteolytic activity dependes on the number and consistency of food. As the meal increases, the secretion of the gastric juice increases.

Evacuation of stomach food in the duodenum is accompanied by braking of gastric secretion. Like an excitement, this process of action mechanism is neurohumoral. The reflex component of this reaction is caused by a decrease in the flow of afferent pulses from the gastric mucosa, to a significantly less irritable liquid food cashem with a pH above 5.0, the increase in the flow of afferent pulses from the mucous membrane of the 12rd intestine (entericastric reflex).

Changes in the chemical composition of food, the receipt of its digestion products in a 12-point intestine stimulate the selection of the nerve endings and endocrine cells of the pyloric stomach, 12 pans and the pancreas of peptides (co-Matostatin, secretine, neurotenzine, hypoda, glucagon, cholecystokinin ), which causes braking of hydrochloric acid products, and then the gastric secretion as a whole. Also prostaglandin of group E is also brake influence on the secretion of main and shell cells.

Other factors affecting gastric secretion

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An important role in the secretory activities of the gastric glands is played by the emotional state of the person and stress. Among the non-silicone factors that enhance the secretory activity of the gastric glands, stress, irritation and rage are most important, the inhibitory braking effect on the activity of the glands is of fear, longing, depressive human states.

Long-term observations of the activity of the secretory apparatus of the stomach in humans made it possible to detect the release of the gastric juice and in the intersection period. In this case, irritants associated with the meal of food were effective (the situation in which food usually occurs), swallowing saliva, while throwing duodenal juices (pancreatic, intestinal, bile) in the stomach).

Badly legged food or accumulating carbon dioxide causes irritation of the mechanic and chemoreceptors of the gastric mucosa, which is accompanied by the activation of the secretory apparatus of the stomach mucosa and the secretion of pepsins and hydrochloric acid.

Spontaneous secretion of the stomach can cause bumps on the skin, burns, abscesses, it occurs in surgical patients in the postoperative period. This phenomenon is associated with the enhanced formation of histamine from the products of the tissue decay, its release from the tissues. With blood stream, histamine reaches the gastric glands and stimulates their secretion.

Questions at the beginning of the paragraph.

Question 1. What methods were used to explore the digestion I. P. Pavlov?

To study the digestion of Pavlov used a fistive method. Fistula is an artificially created hole to eliminate outward products located in stripe organs or glands. So, in order to investigate the separation of salivary gland, I. P. Pavlov derived one of its ducts outside and collected saliva. This gave the opportunity to get it in its pure form and explore the composition. It was found that saliva is distinguished both when food in the oral cavity, and in its form, but provided that the animal is familiar with the taste of this food.

Question 2. How are the unconditional and conditional reflexes differ?

At the proposal I. P. Pavlova, reflexes were divided into unconditional and conditional.

Unconditional reflexes - congenital reflexes characteristic of all individuals of this species. With age, they may vary, but according to a strictly defined program, the same for all individuals of this species. Unconditional reflexes are a reaction to vital events: food, danger, pain, etc.

Conditional reflexes are reflexes acquired during life. They allow the body to adapt to changing conditions, accumulate life experience.

Question 3. How does hunger and saturation arise?

Question 4. How is the gumoral regulation of digestion?

After the nutrients are seen in the blood, the gumoral branch of the gastric juice begins. Among the nutrients there are biologically active substances that, for example, are contained in vegetable and meat decoctions. The products of their splitting through the mucous membrane of the stomach are absorbed into the blood. With blood current, they fall to the glands of the stomach and those begin to highlight the gastric juice. This allows for a long fidelization: proteins are digested slowly, sometimes for 6 hours or more. Thus, the gastric juice is adjustable both nervous and humoral.

Questions at the end of the paragraph.

Question 1. Slyunolation of the dog in the form of a feeder with food - Reflex conditional or unconditional?

This reflex is conditional.

Question 2. How do the feelings of hunger and saturation arise?

The feeling of hunger occurs when the stomach is emptied, and disappears when it is filled, while the feeling of saturation appears. There is a brake reflex to filling the stomach, which warns from overeating.

Question 3. How is the gumoral regulation of gastric juvenoculation?

Products cleaving biologically active substances through the gastric mucous membrane are absorbed into the blood. The blood flow falls to gastric glands and cause a juice that continues throughout the duration, while food is in the stomach.

The formation and separation of gastric juice is controlled by nervous and humoral mechanisms.

The branch of the gastric juice occurs in 2 phases:

1) The first phase of secretion - reflexocate juice:

· Certainly - reflex, Gastric juice is distinguished when irritating the olfactory oral receptors of the oral cavity, pharynx, esophagus;

· Conditional - reflex Sokootdiment occurs when irritating visual, olfactory, auditory receptors, i.e. in appearance, smell of food, etc.

Juice separated at the same time, Pavlov called outstable or appetizing -oNPROPOWS the stomach to the perception of food. It was studied when experiments with "Imaginary feeding "When food is only in the oral cavity, but does not fall into the stomach, and falls through the hole in the esophagus.

2) Second phase of secretion - gastric or neurogumoral, related to the irritation of food mucous membrane receptors: mechanical and chemical irritation → Sensitive neuron → The oblong brain → Motor neuron → Worker (juice isolation).Starts immediately after meals and lasts 2 hours.

Nervous Regulation Centers:

Digestion, salivation,

sokotduke - the oblongable brain;

Hunger and saturation - intermediate brain;

Tusk Zone - Front Brain

Defecation - spinal cord.

Strong stimuli are protein digestion products (meat, fish, vegetable beams), mineral salts, water. The selection of the gastric juice occurs until food is food in the stomach: fatty food is digested 7-8 hours, carbohydrate - much faster.

Gumoral phase regulation : The gastric mucosa highlights a hormone into blood gastrin,he gets into the gland and happens activation of secretion of gastric juice and regulation of the peristalsis of the stomach and intestines (begins 2 hours after meals, carried out by its own hormones of the gastrointestinal tract ( histamine, Gastrin, Secretin)). In addition, hormones of the front proportion of pituitary glands and adrenal cortex contribute to the synthesis of digestive enzymes. Sympathetic Vegetative nervous system tORMEMIT, and parasimpatic – stimulates Selection of digestive juices.

The great merit in the study of the physiology of digestion belongs to Pavlov, who proposed and used the following methods:· Fistula method; · Method of fistula stomach with peasant esophagus (imaginary feeding); · Formation of "insulated ventricle".

With the help of the first two methods, the existence of the first phase of the gastric secretion was proved, the third is the existence of the second phase of secretion.

The fistula of the stomach is displayed on the outdoor side of the abdominal wall. In the formation experiments "Isolated ventricle", When a small ventricle was separated from the stomach of the stomach, and the fistula was imposed on it with maintaining innervation and blood supply, it was possible to get pure gastric juice. This made it possible to find out that the amount and composition of the juice allocated depends on the chemical composition of food - there is more juice with the greatest content of enzymes on protein food, for carbohydrates - less, and on the containing fats - even less.

Stomber functions:

Mechanical

Table of contents of the topic "The intestinal suction feature. Digestion in the oral cavity and a swallowing function.":
1. Suction. The intestinal suction feature. Transport of nutrients. Brush kime enterocyte. Hydrolysis of nutrients.
2. Suction macromolecules. Transcitosis. Endocytosis. Exocytosis. Suction with micromolecules enterocytes. Suction of vitamins.
3. Nervous regulation of secretion of digestive juices and motility of the stomach and intestines. Reflex arc of central esophageal - intestinal motor reflex.
4. Humoral regulation of secretion of digestive juices and motors of the stomach and intestines. Hormonal regulation of the digestive tract.
5. Scheme of the mechanisms for regulating the functions of the gastrointestinal tract (gastrointestinal tract). The generalized scheme of the mechanisms for regulating the functions of the digestive tract.
6. Periodic activity of the digestive system. Hungry periodic activity of the digestive tract. Migrating motor complex.
7. Digestion in the oral cavity and swallowing function. Oral cavity.
8. Saliva. Salivation. Number of saliva. The composition of saliva. Primary secret.
9. Saliva separation. Saliva secretion. Regulation of saliva isolation. Regulation of the secretion of saliva. Center salivation.
10. Chewing. Act chewing. Chewing regulation. Chewing center.

Gumoral regulation of secretion of digestive juices and stomach and intestinal motility. Hormonal regulation of the digestive tract.

Central, peripheral and local reflexes are carried out in close cooperation with humoral mechanism of regulation of myocytes, Glandulocytes and nerve cells.

In the mucous membrane of the gastrointestinal tract and in the pancreas are available endocrine cellswhich produce gastrointe-stynal hormones (regulatory peptides, eniterins). These hormones Through blood flow and local (Paraconno, diffusing through the intercellular fluid) affect myocytes, glandulocytes, intramural neurons and endocrine cells. Their development is launched reflexively (through a wandering nerve) during food intake and for a long time maintained due to the irritant influence of food hydrolysis products and extractive substances.

Table 11.1. Hormones of the gastrointestinal tract, the place of their formation and the effects caused by them

Name of hormone	Place of Hormon Development	Types of endocrine cells	Effect of the action of hormones
Somatostatin	Stomach, proximal department of small intestine, pancreas	D-cells	Inhibits the release of insulin and glucagon, most of the well-known gastrointestinal hormones (secretine, gip, motililine, gastrin); inhibits the activity of parietal cells of the stomach and acinar cells of the pancreas
Vasoactive intestinal (VIP) peptide	In all departments of the gastrointestinal tract	D-cells	Inhibits the action of cholecystokinin, secretion of hydrochloric acid and pepsin stomach, stimulated by histamine, relaxes smooth muscles of blood vessels, gallbladder
Pancreatic polypeptide (PP)	Pancreas	D2 cells	The HCC-PZ antagonist, enhances the proliferation of the mucous membrane of the small intestine, pancreas and liver; Participates in the regulation of carbohydrate and lipid exchange
Gastrin	Anthral part of the stomach, pancreas, proximal dental department	G-cells	Stimulates the secretion and separation of pepsin with gastric glands, excites the motility of a relaxed stomach and duodenal intestine, as well as the gallbladder
Gastron.	Anthral stomach department	G-cells	Reduces the volume of gastric secretion and an acid yield in gastric juice
Bull horror	Anthral stomach department	G-cells	Inhibits secretion and stomach motor
Duokrinin	Anthral stomach department	G-cells	Stimulates the allocation of the Secret of the Brunner Gills of the duodenum
Bombzin (Gastrin-bobbing peptide)	Stomach and proximal dental department	R-cells	Stimulates the release of the gastrin, enhances the reduction of the gallbladder and the release of the ferrustary iron enzymes, enhances the release of enteroglucagon
Secretin	Small intestine	S-cells	Stimulates the secretion of bicarbonates and water with pancreas, liver, brunner glands, pepsin; inhibits secretion in the stomach
Cholecystokinin-Pancreosimine (HCC-PZ)	Small intestine	I-cells	Excites the yield of enzymes and in a weak degree stimulates the yield of bicarbonate of the pancreas, slows down the secretion of hydrochloric acid in the stomach, enhances the reduction of the gallbladder and biliary release, increases the motility of the small intestine
Enteroglukgon	Small intestine	EC1 cells	Inhibits the secretory activity of the stomach, reduces the content of K + in the gastric juice and increases the CA2 + content, slows down the stomach and small intestine
Motine	Proximal dental department	EC2-cells	It excites the secretion of pepsin stomach and secretion of the pancreas, speeds up the evacuation of the contents of the stomach
Gastroincing peptide (hypoda)	Small intestine	K-cells	Inhibits the release of hydrochloric acid and pepsin, the release of gastrin, the stomach motor, excites the secretion of the colon
Neurotenzin	Distal Divine	N-cells	Inhibits the secretion of hydrochloric acid with glands of the stomach, enhances the release of glucagon
Enkephalins (endorphins)	The proximal department of the small intestine and pancreas	L-cells	Inhibits the secretion of pancreas enzymes, enhances the release of gastrin, excites the stomach motor
Substance R.	Small intestine	EC1 cells	Enhances intestinal motor, salivation, inhibits insulin release
Villikinin	Duodenum	EC1 cells	Stimulates Rhythmic Reducing Pork Village
Enterogastron	Duodenum	EC1 cells	Brakes secretory activity and stomach motor
Serotonin	Gastrointestinal	EC1, EC2 cells	Inhibits the extraction of hydrochloric acid in the stomach, stimulates the selection of pepsin, activates the secretion of the pancreas, biliary release, intestinal secretion
Histamine	Gastrointestinal	EC2-cells	Stimulates the allocation of the stomach and pancreas secretion, expands blood capillaries, has an activating effect on the stomach and intestine motorcy
Insulin	Pancreas	Beta cells	Stimulates the transport of substances through cell membranes, contributes to the utilization of glucose and the formation of glycogen, is inhibits lipolysis, lipogenesis activates, increases the intensity of protein synthesis
Glucagon	Pancreas	Alpha cells	Mobilizes carbohydrates, slows down the secretion of the stomach and pancreas, brakes the motility of the stomach and intestines

The place of development of the main gastrointestinal hormonesThe effects caused by them and their cell producing their presented in Table. 11.1. Currently, about 30 regulatory peptides were detected. As follows from the presented table, they have a stimulating, braking and modulating effect on the secretion of digestive juices, a motility of a smooth muscles of the gastrointestinal tract, suction, separation of entering the endocrine elements of the gastric mucosa, intestines and pancreas.

Selection of gastrointestinal hormones has a cascade character. For example, under the influence of gastroin, shelter bonded gland cells increase the production of hydrochloric acid, which in the mucous membrane of the small intestine stimulates the selection of S- and J-cells of secretine and cholecy-stocking - pancreativity. Secretin enhances the secretion of water and bicarbonate pancreas and liver, and cholecystokinin - pancreatimine - excites the separation of ferrustary enzymes and slows down the secretion of hydrochloric acid by cladded cells, enhances the motility of the small intestine and the gallbladder.

Regulatory peptidesWhen entering the bloodstream, quickly destroyed in the liver and kidneys and thereby create conditions for the effects of other gastrointestinal hormones.

Developing some enterinov Wears cyclic nature and can be carried out in the absence of a food stimulus. For example, Mo Tinin, produced by EC2 cells of the proximal portion of the small intestine, causes contraction of the muscles of the stomach and intestines, coinciding with the periods of the "hungry" activity of the digestive tract.

Regulation of gastric secretion I.P. Pavlov specifically divided into three phases. I Phase - fROMFLEFELLY(Brain, Cefalic) consists of conditional and unconditional reflex mechanisms. The kind of food, the smell of food, conversations about it cause a conventional reflex fooling. Estimated juice I.P. Pavlov called appetizing, "fastened."

This juice prepares the stomach to receive food, has high acidity and enzymatic activity, so such juice in an empty stomach can have a damaging effect (for example, the type of food and the absence of the possibility of its reception, the chewing of the chewing gum on an empty stomach). The unconditional reflex is included in the irritation of the food receptors of the oral cavity.

Fig.6 Scheme of unconditional reflex regulation of gastric secretion

1 - Facial nerve, 2 -Yavricade nerve, 3 - upper bad nerve, 4 - sensitive fibers of the wandering nerve, 5 - efferent fibers of the wandering nerve, 6 - postganglionic sympathetic fiber, G is a cell, secreting gastrin.

The presence of a complex flexor phase of the gastric secretion proves the experience of "imaginary feeding". Experience is carried out on a dog, which was previously performed operations of the imposition of fistulas of the stomach and esophagotomy (the esophagus was cut, and its ends were seen in the cut on the skin of the neck). Experiments are made after the recovery of the animal. When feeding such a dog, food fell out of the esophagus, not falling into the stomach, but the gastric juice was distinguished through the open fistula of the stomach. When feeding raw meat for 5 minutes, the gastric juice is allocated 45-50 minutes. The juice discrepanted with high acidity and proteolytic activity. In this phase, the wandering nerve activates not only the cells of the glands of the stomach, but also G-cells, which secrete gastrin (Fig. 6).

II phase of gastric secretion - zastreat - related to the flow of food in the stomach. The filling of the stomach of food excites the mechanoreceptors, information from which by sensitive fibers of the wandering nerve is sent to its secretory core. Efferent parasympathetic fibers of this nerve stimulate gastric secretion. Thus, the first component of the gastric phase is purely reflex (Fig. 6).

Control of food and products of its hydrolysis from the gastric mucosa excites chemoreceptors and activates local reflex and humoral mechanisms. As a result G.- the cells of the pyloric department allocate gastrin hormone,activating the main cells of the glands and, especially, the shelter cells. Puffed cells (ECL) highlight histamine, stimulating parietal cells. The central reflex regulation is complemented by a long time in the time of humoral regulation. The gastrophi secretion increases when the products of digestion of proteins - oligopeptides, peptides, amino acids and depends on the pH in the pyloric sector of the stomach appear. If the secretion of hydrochloric acid is raised, then the gastroy is released less. At pH-1.0, its secretion stops, while the volume of the gastric juice decreases sharply. Thus, self-regulation of gastrin secretion and hydrochloric acid is carried out.

Gastrin: Stimulates the secretion of HCl and pepsinogen, enhances the motility of the stomach and intestines, stimulates pancreatic secretion, activates the growth and restoration of the gastric and intestine mucosa.

In addition, food contains biologically active substances (for example, meat extractive substances, vegetable juices), which also excite mucosa receptors and stimulate the juice in this phase.

The synthesis of HCl is associated with the aerobic oxidation of glucose and the formation of ATP, the energy that the system of active transport ions H + is used. In the apical membrane is built H. + / K. + ATP-AZA, which pumps out of the cageH. + ions in exchange for potassium. One of theories believes that the main supplier of hydrogen ions is coalic acid formed as a result of hydration of carbon dioxide, this reaction catalyzes carboangeerase. Anion of coalic acid leaves the cell through the basal membrane in exchange for chlorine, which is then displayed through the chlorine channels of the apical membrane. Another theory as a source of hydrogen considers water (Fig. 7).

Fig.7. SecretionHCL Clamp and regulation of secretion. Iona N. + Move into lumen with the participation of the N-K-ATPase built into the apical membrane. IonsCl. - In the cell enter the NSO ions 3 - and are removed through the chlorine channels of the apical membrane; Iona N. + Form from N. 2 SO 3 And to a lesser extent - from the water.

It is believed that the parietal cells of the glands of the stomach are excited in three ways:

the wandering nerve has a direct impact on the muscarinic cholinoreceptors (M-cholinoreceptors) and indirect, activating the G-cells of the pyloric stomach.

gastrine has a direct impact on them through specific M-receptors.

gastrin activates ECL (obese) cells secreting histamine. Histamine through H 2 -receptors activates parietal cells.

The blockade of cholinoreceptors atropine reduces the secretion of hydrochloric acid. Blockers H 2 receptors and M-cholinoreceptors are used in the treatment of hyperacid states of the stomach. Braking secretion of hydrochloric acid causes a hormone secretine. Its secretion depends on the pH of the contents of the stomach: the higher the acidity of the chimus entering the 12-russian intestine, the more secretine is allocated. Fat food stimulates the secretion of cholecystokinin (HC). HC reduces the stomach juice and inhibits the activity of parietal cells. Reduce the secretion of hydrochloric acid and other hormones and peptides: glucagon, gip, vip, somatostatin, neurotenzine.

III Phase - intestinal - Begins with the evacuation of Hamus from the stomach into the small intestine. Irritation of mechanical, chemoreceptors of the small intestine products of food digestion regulates secretion mainly due to local nervous and humoral mechanisms. Enterogastrine, bombiness, motilin is secreted by endocrine cells of the mucous layer, these hormones increase the juice. VIP (vasoactive intestinal peptide), somatostatin, bulbon, secretine, hystown (gastroincing peptide) - inhibit gastric secretion under action on the mucous membrane of the small intestine of fats, hydrochloric acid, hypertensive solutions.

Thus, the secretion of the gastric juice is under the control of central and local reflexes, as well as many hormones and biologically active substances.

The amount of juice, the speed of secretion and its composition depends on the quality of the food, as evidenced by the coil curves obtained in the laboratory I.P. Pavlov with the introduction of dogs in the stomach of the same bread, meat, milk. The strongest stimulants of gastric secretion are meat and bread. When consumed, a lot of juice with high proteolytic activity is released.