SEMIOTICS OF DISEASES OF THE DIGESTIVE ORGANS

Diseases of the digestive system in children of preschool and school age are 79.3 cases per 1000 children. The proportion of functional disorders of the digestive system in children decreases with age, and at the same time the frequency of organic diseases increases. For the diagnosis of diseases of the digestive system, the analysis of complaints, knowledge and consideration of the anatomical and physiological characteristics of the gastrointestinal tract of a child is important.

ANATOMO-PHYSIOLOGICAL FEATURES OF THE GASTROINTESTINAL TRACT IN CHILDREN

The formation of the digestive organs begins from the 3-4th week of the embryonic period, when the primary intestine is formed from the endodermal plate. At the front end of it at the 4th week, a mouth opening appears, and a little later, an anus appears at the opposite end. The intestine is rapidly lengthening, and from the 5th week of the embryonic period, the intestinal tube is divided into two sections, which are the basis for the formation of the small and large intestines. During this period, the stomach begins to stand out - like an expansion of the primary intestine. At the same time, the mucosa, muscle and serous membranes of the gastrointestinal tract are formed, in which blood and lymphatic vessels, nerve plexuses, and endocrine cells are formed.

In the first weeks of pregnancy, the endocrine apparatus of the gastrointestinal tract is laid in the fetus and the production of regulatory peptides begins. In the process of intrauterine development, the number of endocrine cells increases, the content of regulatory peptides in them increases (gastrin, secretin, motilin, gastric inhibitory peptide (GIP), vaso-active intestinal peptide (VIP), enterogljagon, somatostatin, neurotensin, etc.). At the same time, the reactivity of target organs in relation to regulatory peptides increases. In the prenatal period, peripheral and central mechanisms of nervous regulation of the activity of the gastrointestinal tract are laid.

In the fetus, the gastrointestinal tract begins to function as early as 16-20 weeks of intrauterine life. By this time, the swallowing reflex is expressed, amylase is found in the salivary glands, pepsinogen in the gastric glands, and secretin in the small intestine. A normal fetus swallows a large amount of amniotic fluid, the individual components of which are hydrolyzed in the intestine and absorbed. The undigested part of the contents of the stomach and intestines goes to the formation of meconium.

During intrauterine development, before implantation of the embryo into the uterine wall, its nutrition occurs due to the reserves in the cytoplasm of the egg. The embryo feeds on the secretions of the uterine lining and the yolk sac material (histotrophic type of nutrition). Since the formation of the placenta, hemotrophic (transplacental) nutrition, provided by the transport of nutrients from the mother's blood to the fetus through the placenta, is of primary importance. It plays a leading role until the baby is born.

From 4-5 months of intrauterine development, the activity of the digestive organs begins and, together with hemotrophic, amniotrophic nutrition occurs. The daily amount of fluid absorbed by the fetus in the last months of pregnancy can reach more than 1 liter. The fetus absorbs amniotic fluid containing nutrients (proteins, amino acids, glucose, vitamins, hormones, salts, etc.) and enzymes that hydrolyze them. Some enzymes enter the amniotic fluid from the fetus with saliva and urine, the second source is the placenta, the third source is the mother's body (enzymes through the placenta and bypassing it can enter the amniotic fluid from the blood of a pregnant woman).

Part of the nutrients is absorbed from the gastrointestinal tract without prior hydrolysis (glucose, amino acids, some dimers, oligomers, and even polymers), since the intestinal tube of the fetus has a high permeability, the fetal enterocytes are capable of pinocytosis. It is important to take this into account when organizing meals for a pregnant woman in order to prevent allergic diseases. Some of the nutrients of the amniotic fluid are digested by its own enzymes, that is, the autolytic type of digestion plays an important role in the amniotic nutrition of the fetus. Amniotrophic nutrition of the type of its own cavity digestion can be carried out from the 2nd half of pregnancy, when pepsinogen and lipase are secreted by the cells of the stomach and pancreas of the fetus, although their level is low. Amniotrophic nutrition and the corresponding digestion are important not only for the supply of nutrients to the blood of the fetus, but also as the preparation of the digestive organs for lactotrophic nutrition.

In newborns and children in the first months of life, the oral cavity is relatively small, the tongue is large, the muscles of the mouth and cheeks are well developed, in the thickness of the cheeks there are fatty bodies (Bisha's lumps), which are distinguished by significant elasticity due to the predominance of solid (saturated) fatty acids in them. These features ensure complete breastfeeding. The mucous membrane of the oral cavity is delicate, dryish, rich in blood vessels (easily vulnerable). The salivary glands are poorly developed, produce little saliva (the submandibular, sublingual glands function to a greater extent in infants, in children after a year and in adults - the parotid). The salivary glands begin to function actively by the 3-4th month of life, but even at the age of 1 year, the volume of saliva (150 ml) is 1/10 of the amount in an adult. The enzymatic activity of saliva at an early age is 1 / 3-1 / 2 of its activity in adults, but it reaches the level of adults within 1 to 2 years. Although the enzymatic activity of saliva is low at an early age, its effect on milk contributes to its curdling in the stomach with the formation of small flakes, which facilitates the hydrolysis of casein. Hypersalivation at 3-4 months of age is caused by teething, saliva can flow out of the mouth due to the inability of children to swallow it. The reaction of saliva in children of the first year of life is neutral or slightly acidic - this can contribute to the development of thrush of the oral mucosa with improper care of it. At an early age, saliva contains a low content of lysozyme, secretory immunoglobulin A, which leads to its low bactericidal activity and the need to observe proper oral care.

The esophagus in young children is funnel-shaped. Its length in newborns is 10 cm, it increases with age, while the diameter of the esophagus becomes larger. Under the age of one year, physiological narrowing of the esophagus is poorly expressed, especially in the area of \u200b\u200bthe cardiac part of the stomach, which contributes to the frequent regurgitation of food in children of the 1st year of life.

The stomach in infants is located horizontally, its bottom and cardiac section are poorly developed, which explains the tendency of children in the first year of life to regurgitate and vomit. As the child begins to walk, the axis of the stomach becomes more vertical, and by the age of 7-11, it is located in the same way as that of an adult. The stomach capacity of a newborn is 30-35 ml, by the year it increases to 250-300 ml, by the age of 8 it reaches 1000 ml. The secretory apparatus of the stomach in children of the 1st year of life is insufficiently developed, in the gastric mucosa they have fewer glands than in adults, and their functional abilities are low. Although the composition of gastric juice in children is the same as in adults (hydrochloric acid, lactic acid, pepsin, rennet, lipase), the acidity and enzymatic activity are lower, which determines the low barrier function of the stomach and the pH of the gastric juice (4-5, in adults, 1.5-2.2). In this regard, proteins are insufficiently cleaved by pepsin in the stomach, they are cleaved mainly by cathepsins and gastrixin produced by the gastric mucosa, their optimum action is at pH 4-5. Lipase of the stomach (produced by the pyloric region of the stomach) breaks down in an acidic medium, together with lipase of human milk, up to half of the fat in human milk. These features must be taken into account when prescribing various types of food for a child. With age, the secretory activity of the stomach increases. Stomach motility in children during the first months of life is slowed down, peristalsis is sluggish. The timing of evacuation of food from the stomach depends on the nature of feeding. Women's milk lingers in the stomach for 2-3 hours, cow's milk - 3-4 hours, which indicates the difficulties of digesting the latter.

The intestines in children are relatively longer than in adults. The cecum is mobile due to the long mesentery; therefore, the appendix can be located in the right iliac region, displaced into the small pelvis and into the left half of the abdomen, which creates difficulties in the diagnosis of appendicitis in young children. The sigmoid colon is relatively long, which predisposes children to constipation, especially if the mother's milk contains an increased amount of fat. The rectum in children in the first months of life is also long, with poor fixation of the mucous and submucous layer, and therefore, with tenesmus and persistent constipation, it may fall out through the anus. The mesentery is longer and more easily stretchable, which can lead to torsion, intussusception and other pathological processes. The onset of intussusception in young children is also facilitated by the weakness of the ileocecal flap. A feature of the intestines in children is the better development of circular muscles than longitudinal muscles, which predisposes to intestinal spasms and intestinal colic. A feature of the digestive organs in children is also the weak development of the small and large omentum, and this leads to the fact that the infectious process in the abdominal cavity (appendicitis, etc.) often leads to diffuse peritonitis.

The intestinal secretory apparatus at the time of the birth of the child is generally formed, the intestinal juice contains the same enzymes as in adults (enterokinase, alkaline phosphatase, lipase, erypsin, amylase, maltase, lactase, nuclease, etc.), but their activity low. Under the influence of intestinal enzymes, mainly of the pancreas, the breakdown of proteins, fats and carbohydrates occurs. However, the pH of the duodenal juice in young children is slightly acidic or neutral, therefore, the breakdown of protein by trypsin is limited (for trypsin, the optimal pH is alkaline). The process of digestion of fats is especially intense due to the low activity of lipolytic enzymes. In breastfed babies, bile-emulsified lipids are broken down by 50% under the influence of breast milk lipase. Digestion of carbohydrates occurs in the small intestine under the influence of pancreatic amylase and intestinal juice disaccharidases. The processes of putrefaction in the intestines do not occur in healthy infants. The structural features of the intestinal wall and its large area determine in young children a higher absorption capacity than in adults and, at the same time, an insufficient barrier function due to the high permeability of the mucous membrane for toxins and microbes.

The motor function of the gastrointestinal tract in young children also has a number of features. The peristaltic wave of the esophagus and mechanical irritation of its lower section with a food lump cause a reflex opening of the entrance to the stomach. Gastric motility consists of peristalsis (rhythmic waves of contraction from the cardiac to the pylorus), peristoli (the resistance exerted by the stomach walls to the stretching action of food) and fluctuations in the tone of the stomach wall, which appears 2-3 hours after eating. The motility of the small intestine includes pendulum movement (rhythmic oscillations that mix intestinal contents with intestinal secretions and create favorable conditions for absorption), fluctuations in the tone of the intestinal wall and peristalsis (worm-like movements along the intestine, promoting the movement of food). In the large intestine, pendulum and peristaltic movements are also noted, and in the proximal regions - antiperistalsis, which contributes to the formation of feces. The time of passage of food gruel through the intestines in children is shorter than in adults: in newborns - from 4 to 18 hours, in older ones - about a day. It should be noted that with artificial feeding, this period is lengthened. The act of defecation in infants occurs reflexively without the participation of a volitional moment, and only by the end of the first year of life, defecation becomes voluntary.

In the first hours and days of life, a newborn excretes original feces, or meconium, in the form of a thick, odorless, dark olive-colored mass. In the future, the feces of a healthy infant have a yellow color, an acid reaction and a sour smell, and their consistency is mushy. At an older age, the chair becomes shaped. Stool frequency in infants is from 1 to 4-5 times a day, in older children - 1 time per day.

The intestines of a child in the first hours of life are almost free of bacteria. Subsequently, the gastrointestinal tract is colonized by microflora. In the oral cavity of an infant, staphylococci, streptococci, pneumococci, Escherichia coli and some other bacteria can be found. Escherichia coli, bifidobacteria, lactic acid bacteria, etc. appear in the feces. With artificial and mixed feeding, the phase of bacterial infection occurs faster. Gut bacteria contribute to the enzymatic digestion of food. With natural feeding, bifidobacteria, lactic acid sticks predominate, in a smaller amount - E. coli. Feces are light yellow with a sour odor, ointment. With artificial and mixed feeding, due to the predominance of decay processes in the feces, there are a lot of E. coli, fermentative flora (bifidoflora, lactic acid sticks) is present in smaller quantities.

afho of the gastrointestinal tract in children

The establishment of the organization of digestion occurs at an early stage of embryonic development. Already by 7-8 days from the endoderm → primary intestine, from which 2 parts are formed on the 12th day: intra-embryonic (future digestive tract), extraembryonic (yolk sac).

From the 4th week of embryogenesis, the formation of various departments begins:

from the anterior gut the pharynx, esophagus, stomach and part of the duodenum with rudiments of the pancreas and liver develop;

from the midgut part of the duodenum, jejunum and ileum is formed;

from the back - all parts of the large intestine develop.

afo

Oral cavity has features that ensure the act of sucking:

relatively small volume of the oral cavity;

big tongue;

good development of the muscles of the mouth and cheeks;

roller-like duplications of the gingival mucosa;

fatty bodies (lumps of Besh);

The salivary glands are underdeveloped.

Esophagus formed for birth. The entrance to the esophagus in a newborn is at the level between the III and IV cervical vertebrae, at the age of 12 - at the level of the VI-VII vertebrae. Funnel-shaped. The length of the esophagus increases with age. Anatomical constrictions are poorly expressed.

The transition of the esophagus to the stomach during all periods of childhood at the level of the X-XI thoracic vertebrae.

Stomach in infants, it is located horizontally. As the baby begins to walk, the axis of the stomach becomes vertical.

newborns have poor fundus and cardiac development

the cardiac sphincter is very poorly developed, and the pyloric sphincter functions satisfactorily  tendency to regurgitate;

there are few glands in the mucous membrane  the secretory apparatus is insufficiently developed and its functional abilities are low;

the composition of the gastric juice is the same, but the acidic and enzymatic activity is lower;

the main enzyme of gastric juice is chymosin (rennet), which ensures milk curdling;

there is little lipase and its low activity;

the timing of evacuation of food from the stomach depends on the type of feeding;

gastrointestinal motility is slowed down, peristalsis is sluggish;

the physiological volume is less than the anatomical capacity and is 7 ml at birth. On the 4th day - 40-50 ml, by the 10th day - up to 80 ml. By the end of 1 year - 250 ml, by 3 years - 400-600 ml. At the age of 4-7 years, the capacity of the stomach increases slowly, by 10-12 years it is 1300-1500 ml.

With the onset of enteral nutrition, the number of gastric glands begins to increase rapidly. If a fetus has 150-200 thousand glands per 1 kg of body weight, a 15-year-old has 18 million.

Pancreas  pancreas is not completely formed at birth;

at birth, weight  3 g, in an adult 30 times more. The gland grows most intensively in the first 3 years and in puberty.

at an early age, the surface of the gland is smooth, and by 10-12 years, tuberosity appears, which is due to the allocation of the boundaries of the lobules. In newborns, the head of the pancreas is most developed;

trypsin, chymotrypsin begins to be secreted in utero; from 12 weeks - lipase, phospholipase A; amylase only after birth;

the secretory activity of the gland reaches the level of secretion of adults by the age of 5;

Liver  the parenchyma is poorly differentiated;

lobulation is detected only by 1 year;

by the age of 8, the morphological and histological structure of the liver is the same as in adults;

insolvent enzymatic system;

at birth, the liver is one of the largest organs (1/3 - 1/2 of the volume of the abdominal cavity, and mass \u003d 4.38% of the total mass); the left lobe is very massive, which is explained by the peculiarities of the blood supply;

the fibrous capsule is thin, there are delicate collagen and elastic fibers;

in children 5-7 years old, the lower edge comes out from under the edge of the right costal arch by 2-3 cm;

a newborn has more water in the liver, at the same time there is less protein, fat, glycogen;

there are age-related changes in the microstructure of liver cells:

in children, 1.5% of hepatocytes have 2 nuclei (in adults - 8.3%);

the granular reticulum of the hepatocyte is less developed;

many free-lying ribosomes in the endoplasmic reticulum of the hepatocyte;

glycogen is found in the hepatocyte, the amount of which increases with age.

Gall bladder in a newborn, it is hidden by the liver, has a fusiform shape  3 cm. Bile differs in composition: poor in cholesterol; bile acids, the content of bile acids in hepatic bile in children aged 4-10 years is less than in children of the first year of life. At the age of 20, their content again reaches the previous level; salts; rich in water, mucin, pigments. With age, the ratio of glycocholic and taurocholic acids changes: an increase in the concentration of taurocholic acid increases the bactericidal capacity of bile. Bile acids in the hepatocyte are synthesized from cholesterol.

Intestines relatively longer in relation to body length (in a newborn 8.3: 1; in an adult 5.4: 1). In young children, in addition, the intestinal loops are more compact, because the small pelvis is not developed.

in young children, there is a relative weakness of the ileocecal valve, and therefore the contents of the cecum, the richest in bacterial flora, can be thrown into the ileum;

due to weak fixation of the rectal mucosa in children, its prolapse can often occur;

the mesentery is longer and more easily extensible  slightly \u003d torsion, intussusception;

short omentum  spilled peritonitis;

the structural features of the intestinal wall and its large area determine a higher absorption capacity and, at the same time, an insufficient barrier function due to the high permeability of the mucous membrane for toxins and microbes;

In children of all ages, the maltase activity of the mucous membrane of the small intestine is high, while its sucrase activity is much lower. The lactase activity of the mucous membrane, noted in the first year of life, gradually decreases with age, remaining at a minimum level in an adult. Disaccharidase activity in older children is most pronounced in the proximal small intestine, where monosaccharides are mainly absorbed.

In children over 1 year old, as in adults, protein hydrolysis products are absorbed mainly in the jejunum. Fats begin to be absorbed in the proximal ileum.

Vitamins and minerals are absorbed in the small intestine. Its proximal sections are the main site of nutrient absorption. The ileum is the reserve absorption zone.

The length of the large intestine in children of different ages is equal to the length of the child's body. By 3-4 years of age, the structure of the large intestine sections of a child becomes similar to the anatomy of the corresponding sections of the intestine of an adult.

The secretion of juice by the glands of the large intestine in children is poorly expressed, but it sharply increases with mechanical irritation of the mucous membrane.

motor activity is very energetic (increased frequency of the act of defecation).

All enzymes are born membrane digestion, have high activity, topography of enzymatic activity throughout the small intestine or distal shift, which reduces the reserve capacity of membrane digestion. In the same time intracellular digestion, carried out by pinocytosis in children of the 1st year of life, is much better expressed.

Transient dysbiosis runs independently from the 4th day

in 60-70% - pathogenetic staphylococcus

in 30-50% - enterobacterial, Candida

10-15% - Proteus

Excreta:

Meconium (intestinal contents, I. Aseptic (sterile) phase.

accumulated before childbirth and before II. Flora colonization phase (dysbacteri

first attachment to the chest; oz coincides with toxic erytherma).

consists of intestinal cells III. The phase of displacement of the flora of bifidobac-

epithelium, amniotic fluid). terium.

Transitional stool (after day 3)

Newborn stool (from the 5th day

birth).

Features of digestion in children

At birth, the salivary glands are formed, but the secretory function is low for 2-3 months. Лю-amylase of saliva is low. By 4-5 months, profuse salivation is observed.

By the end of the 1st year, hydrochloric acid appears in the gastric juice. Among proteolytic enzymes, the predominant action is renin (chymosin) and gastrixin. Relatively high activity of gastric lipase.

At birth, the endocrine function of the pancreas is immature. Pancreatic secretion rapidly increases after the introduction of complementary foods (with artificial feeding, the functional maturation of the gland is ahead of that with natural). Especially low amylolytic activity.

Liver relatively large at birth, but functionally immature. The release of bile acids is small, at the same time, the liver of a child in the first months of life has a greater "glycogen capacity".

Intestines in newborns, as it were, compensates for the insufficiency of those organs that provide distant digestion. Of particular importance is membrane digestion, whose enzymes are highly active. The topography of enzymatic activity throughout the small intestine in newborns has a distal shift, which reduces the reserve capacity of membrane digestion. In the same time intracellular digestion, carried out by pinocytosis, in children of the 1st year is much better expressed than at an older age.

During the 1st year of life, there is a rapid development distant digestion, the value of which is increasing every year.

Disaccharides (sucrose, maltose, isomaltose), like lactose, undergo hydrolysis in the small intestine by the corresponding disaccharidases.

The digestive organs include the oral cavity, esophagus, stomach and intestines. The pancreas and liver are involved in digestion. The digestive organs are laid in the first 4 weeks of the prenatal period; by the 8th week of pregnancy, all parts of the digestive organs are determined. The fetus begins to swallow the amniotic fluid by 16-20 weeks of gestation. Digestive processes take place in the intestines of the fetus, where an accumulation of primary feces, meconium, is formed.

Features of the oral cavity in children

The main function of the oral cavity in a child after birth is to provide the sucking act. These features are: small size of the oral cavity, large tongue, well-developed musculature of the lips and chewing muscles, transverse folds on the mucous membrane of the lips, roller-like thickening of the gums, in the cheeks there are lumps of fat (Bisha's lumps), which give elasticity to the cheeks.

The salivary glands in children are not sufficiently developed after birth; little saliva is released in the first 3 months. The development of the salivary glands is completed by 3 months of age.

Features of the esophagusin children

The esophagus in young children has a fusiform shape, it is narrow and short. In a newborn, its length is only 10 cm, in children at the age of 1 year - 12 cm, at 10 years old - 18 cm. Its width, respectively, is 8 mm at 7 years old, and 15 mm at 12 years old.

There are no glands on the mucous membrane of the esophagus. It has thin walls, poor development of muscle and elastic tissues, and is well supplied with blood. The entrance to the esophagus is high. He has no physiological constrictions.

Features of the stomachin children

In infancy, the stomach is horizontal. As the child grows and develops during the period when the child begins to walk, the stomach gradually assumes an upright position, and by the age of 7-10 years it is located in the same way as in adults. The capacity of the small mouth gradually increases: at birth it is 7 ml, at 10 days - 80 ml, a year - 250 ml, at 3 years old - 400-500 ml, at 10 years old - 1500 ml.

V \u003d 30 ml + 30 x n,

where n is the age in months.

The peculiarity of the stomach in children is the poor development of its fundus and cardiac sphincter against the background of good development of the pyloric region. This contributes to frequent regurgitation in a child, especially if air enters the stomach during sucking.

The mucous membrane of the stomach is relatively thick; against this background, there is a weak development of the gastric glands. As the child grows, the active glands of the gastric mucosa are formed and enlarged 25 times, as in the adult state. In connection with these features, the secretory apparatus in children of the first year of life is insufficiently developed. The composition of gastric juice in children is similar to that of adults, but its acidic and enzymatic activity is much lower. The barrier activity of gastric juice is low.

The main active enzyme of gastric juice is rennet (labenzyme), which provides the first phase of digestion - milk curdling.

Very little linden is secreted in the stomach of an infant. This deficiency is compensated for by the presence of lipase in breast milk, as well as in the baby's pancreatic juice. If a baby receives cow's milk, the fats in the stomach are not broken down.

Absorption in the stomach is insignificant and concerns such substances as salts, water, glucose, and protein breakdown products are only partially absorbed. The timing of evacuation of food from the stomach depends on the type of feeding. Human milk is retained in the stomach for 2-3 hours.

Features of the pancreas in children

The pancreas is small. In a newborn, its length is 5-6 cm, and by 10 years of age, it triples. The pancreas is located deeply in the abdominal cavity at the level of the X thoracic vertebra; at an older age, it is located at the level of the I lumbar vertebra. Its intensive growth occurs until the age of 14.

The size of the pancreas in children in the first year of life (cm):

1) newborn - 6.0 x 1.3 x 0.5;

2) 5 months - 7.0 x 1.5 x 0.8;

3) 1 year - 9.5 x 2.0 x 1.0.

The pancreas is richly supplied with blood vessels. Its capsule is less dense than in adults, and consists of fine-fibrous structures. Its excretory ducts are wide, which ensures good drainage.

The child's pancreas has exocrine and intrasecretory functions. It produces pancreatic juice, which consists of albumins, globulins, trace elements and electrolytes, enzymes necessary for the digestion of food. The enzymes include proteolytic enzymes: trypsin, chymotrypsin, elastase, as well as lipolytic enzymes and amylolytic enzymes. The regulation of the pancreas is provided by secretin, which stimulates the separation of the liquid part of pancreatic juice, and pancreosimin, which enhances the secretion of enzymes along with other hormone-like substances produced by the mucous membrane of the duodenum and small intestine.

The intrasecretory function of the pancreas is performed due to the synthesis of hormones responsible for the regulation of carbohydrate and fat metabolism.

LIVER: features in children

The liver of a newborn is the largest organ, occupying 1/3 of the volume of the abdominal cavity. At 11 months, its mass doubles, by 2-3 years it triples, by 8 years it increases 5 times, by 16-17 years the mass of the liver - 10 times.

The liver performs the following functions:

1) produces bile, which is involved in intestinal digestion;

2) stimulates intestinal motility due to the action of bile;

3) deposits nutrients;

4) carries out a barrier function;

5) participates in the metabolism, including the transformation of vitamins A, D, C, B12, K;

6) in the prenatal period it is a hematopoietic organ.

After birth, further formation of up to the liver takes place. The functional capabilities of the liver in young children are low: in newborns, the metabolism of indirect bilirubin is incomplete.

Features of the gallbladder in children

The gallbladder is located under the right lobe of the liver and has a fusiform shape, its length reaches 3 cm. It acquires a typical pear-shaped shape by 7 months, by the 2nd ladies it reaches the edge of the liver.

The main function of the gallbladder is the accumulation and secretion of hepatic bile. The composition of the bile of a child differs from that of an adult. It contains little bile acids, cholesterol, salts, a lot of water, mucin, pigments. In the neonatal period, bile is rich in urea. In the child's bile, glycocholic acid prevails and enhances the bactericidal effect of bile, and also accelerates the separation of pancreatic juice. Bile emulsifies fats, dissolves fatty acids, improves peristalsis.

With age, the size of the gallbladder increases, bile of a different composition begins to be secreted than in younger children. The length of the common bile duct increases with age.

The size of the gallbladder in children (Chapova O.I., 2005):

1) newborn - 3.5 x 1.0 x 0.68 cm;

2) 1 year - 5.0 x 1.6 x 1.0 cm;

3) 5 years old - 7.0 x 1.8 x 1.2 cm;

4) 12 years old - 7.7 x 3.7 x 1.5 cm.

Features of the small intestine in children

The intestines in children are relatively longer than in adults.

The ratio of the length of the small intestine to body length in a newborn is 8.3: 1, in the first year of life - 7.6: 1, at 16 years old - 6.6: 1.

The length of the small intestine in a child of the first year of life is 1.2-2.8 m. The area of \u200b\u200bthe inner surface of the small intestine in the first week of life is 85 cm2, in an adult it is 3.3 x 103 cm2. The area of \u200b\u200bthe small intestine increases due to the development of epithelium and microvilli.

The small intestine is anatomically divided into 3 sections. The first section is the duodenum, the length of which in the newborn is 10 cm, in the adult it reaches 30 cm.It has three sphincters, the main function of which is to create an area of \u200b\u200blow pressure, where food contacts with pancreatic enzymes.

The second and third sections are represented by the small intestine and ileum. The length of the small intestine is 2/5 of the length to the ileocecal angle, the remaining 3/5 is the ileum.

Digestion of food, absorption of its ingredients occurs in the small intestine. The intestinal mucosa is rich in blood vessels, the epithelium of the small intestine is rapidly renewed. Intestinal glands in children are larger; lymphoid tissue is scattered throughout the intestine. As the child grows, Peyer's patches form.

Features of the large intestine in children

The large intestine is divided into different sections and develops after birth. In children under 4 years of age, the ascending intestine is longer in length than the descending one. The sigmoid colon is relatively long. Gradually, these features disappear. After soldering, the intestine and appendix are mobile, and the appendix is \u200b\u200boften atypical.

The rectum in children in the first months of life is relatively long. In newborns, the ampulla of the rectum is undeveloped, the surrounding fatty tissue is poorly developed. By the age of 2 years, the rectum assumes its final position, which promotes prolapse of the rectum in early childhood with straining, with persistent constipation and tenesmus in weakened children.

The omentum in children under 5 years of age is short.

Juice production in children in the large intestine is small, but with mechanical irritation it increases sharply.

In the large intestine, water is absorbed and feces are formed.

Features of intestinal microflorain children

The fetal gastrointestinal tract is sterile. When a child comes into contact with the environment, it is populated with microflora. In the stomach and duodenum, the microflora is scarce. In the small and large intestines, the number of microbes increases and depends on the type of feeding. The main microflora is B. bifidum, whose growth is stimulated by breast milk lactose. With artificial feeding, conditionally pathogenic gram-negative Escherichia coli dominates in the intestine. The normal intestinal flora has two main functions:

1) creation of an immunological barrier;

2) synthesis of vitamins and enzymes.

Features of digestion in young children

For children in the first months of life, the nutrients that come with the mother's milk and are digested due to the substances contained in the human milk itself are of decisive importance. With the introduction of complementary foods, the mechanisms of the child's enzyme systems are stimulated. The absorption of food ingredients in young children has its own characteristics. Casein is first curdled in the stomach under the influence of a foreign enzyme. In the small intestine, it begins to break down into amino acids, which are activated and absorbed.

The digestion of fat depends on the type of feeding. Cow's milk fats contain long-chain fats that are degraded by pancreatic lipase in the presence of fatty acids.

Fat absorption occurs in the final and middle sections of the small intestine. The breakdown of milk sugar in children occurs in the border of the intestinal epithelium. Human milk contains lactose, cow's milk contains lactose. In this regard, with artificial feeding, the carbohydrate composition of food is changed. Vitamins are also absorbed in the small intestine.

Young children (especially newborns) have a number of morphological features common to all parts of the gastrointestinal tract: 1) thin, delicate, dry, easily injured mucous membrane; 2) a richly vascularized submucosal layer, consisting mainly of loose fiber; 3) insufficiently developed elastic and muscle tissue; 4) low secretory function of the glandular tissue, which separates a small amount of digestive juices with a low content of enzymes. These features make it difficult to digest food, if the latter does not correspond to the child's age, reduce the barrier function of the gastrointestinal tract and lead to frequent diseases, create the prerequisites for a general systemic response to any pathological effect and require very careful and careful care of the mucous membranes.

Oral cavity.In a newborn and a child in the first months of life, the oral cavity has a number of features that ensure the act of sucking. These include: a relatively small volume of the oral cavity and a large tongue, good development of the muscles of the mouth and cheeks, roller-like duplicates of the gingival mucosa and transverse folds on the mucous membrane of the lips, fatty bodies (Bisha's lumps) in the thickness of the cheeks, characterized by significant elasticity due to the predominance they contain solid fatty acids. The salivary glands are underdeveloped. However, insufficient salivation is mainly due to the immaturity of the nerve centers that regulate it. As they mature, the amount of saliva increases, and therefore, at 3 to 4 months of age, the child often develops the so-called physiological salivation due to the not yet developed automatism of swallowing it.

Esophagus.In young children, the esophagus is funnel-shaped. Its length in newborns is 10 cm, in children 1 year old - 12 cm, 10 years old - 18 cm, diameter - 7 - 8, 10 and 12-15 mm, respectively, which must be taken into account when carrying out a number of medical and diagnostic procedures.

Stomach.In infants, the stomach is located horizontally, with the pyloric part located near the midline, and the lesser curvature facing posteriorly. As the baby begins to walk, the axis of the stomach becomes more vertical. By the age of 7-11, it is located in the same way as in adults (Fig. 10-12). The capacity of the stomach in newborns is 30 - 35 ml, by 1 year it increases to 250 - 300 ml, by the age of 8 it reaches 1000 ml. The cardiac sphincter in infants is very poorly developed, and the pyloric sphincter functions satisfactorily. This contributes to the regurgitation, which is often seen at this age, especially when the stomach is distended due to the swallowing of air during sucking ("physiological aerophagy"). There are fewer glands in the stomach lining of young children than in adults. And although some of them begin to function even in utero, in general, the secretory apparatus of the stomach in children of the first year of life is insufficiently developed and its functional abilities are low. The composition of gastric juice in children is the same as in adults (hydrochloric acid, lactic acid, pepsin, rennet, lipase, sodium chloride), but acidity and enzyme activity are much lower (Table 3), which not only affects digestion, but also determines the low barrier function of the stomach. This makes it absolutely necessary to carefully observe the sanitary and hygienic regime during feeding of children (breast toilet, clean hands, correct expression of milk, sterility of nipples and bottles). In recent years, it has been established that the bactericidal properties of gastric juice are provided by lysozyme produced by the cells of the surface epithelium of the stomach.

As you can see from the table. 3, the acidity indicators fluctuate significantly, which is explained by the individual characteristics of the formation of gastric secretion and the age of the child.

Determination of acidity is carried out by the fractional method using 7% cabbage broth, meat broth, 0.1 % solution of histamine or pentagastrin. The main active enzyme of gastric juice is chymosin (rennet, labenzyme), which provides the first phase of digestion - milk curdling. Pepsin (in the presence of hydrochloric acid) and lipase continue the hydrolysis of proteins and fats in curdled milk. However, the value of gastric acid lipase in the digestion of fats is small due to its extremely low content and low activity. This deficiency is compensated for by lipase, which is found in human milk, as well as in the baby's pancreatic juice. Therefore, in infants who receive only cow's milk, the fat in the stomach is not broken down. The maturation of the secretory apparatus of the stomach occurs earlier and more intensively in children who are bottle-fed, which is associated with the adaptation of the body to more difficult to digest food. The functional state and enzymatic activity depend on many factors: the composition of the ingredients and their quantity, the emotional tone of the child, his physical activity, and general condition. It is well known that fats suppress gastric secretion, proteins stimulate it. Depressed mood, fever, intoxication are accompanied by a sharp decrease in appetite, i.e., a decrease in gastric acid secretion. Absorption in the stomach is insignificant and mainly concerns substances such as salts, water, glucose, and only partially - protein breakdown products. Stomach motility in children in the first months of life is slowed down, peristalsis is sluggish, the gas bubble is enlarged. The timing of evacuation of food from the stomach depends on the nature of feeding. So, female milk is retained in the stomach for 2-3 hours, cow's milk - for a longer time (3-4 hours and even up to 5 hours, depending on the buffer properties of milk), which indicates the difficulties of digesting the latter and the need to switch to more rare feedings.

Pancreas.In a newborn, the pancreas is small (length 5 - 6 cm, by 10 years - three times more), located deep in the abdominal cavity, at the level of the X thoracic vertebra, in subsequent age periods - at the level of the I lumbar vertebra. It is richly vascularized, intensive growth and differentiation of its structure continues up to 14 years. The capsule of the organ is less dense than in adults, consists of fine-fibrous structures, and therefore in children with inflammatory edema of the pancreas, its compression is rarely observed. The excretory ducts of the gland are wide, which provides good drainage. Close contact with the stomach, mesentery root, solar plexus and common bile duct, with which the pancreas in most cases has a common outlet to the duodenum, often leads to a friendly reaction from the organs of this zone with a wide irradiation of pain.

The pancreas in children, as in adults, has external and intrasecretory functions. The exocrine function is to produce pancreatic juice. It contains albumins, globulins, trace elements and electrolytes, as well as a large set of enzymes necessary for the digestion of food, including proteolytic (trypsin, chymopsin, elastase, etc.), lipolytic (lipase, phospholipase A and B, etc.) and amylolytic (α- and (beta-amylase, maltase, lactase, etc.). The rhythm of pancreatic secretion is regulated by neuro-reflex and humoral mechanisms. enhancing the secretion of enzymes along with other hormones (cholecystokinin, hepatokinin, etc.) produced by the mucous membrane of the duodenum and jejunum under the influence of hydrochloric acid.The secretory activity of the gland reaches the level of secretion of adults by the age of 5. The total volume of secreted juice and its composition depend on the amount and the nature of the food eaten.The intrasecretory function of the pancreas is carried out by synth ez hormones (insulin, glucagon, lipocaine) involved in the regulation of carbohydrate and fat metabolism.

Liver.In children, the liver is relatively large, its weight in newborns is 4 - 6% of the body weight (in adults - 3%). The parenchyma of the liver is poorly differentiated, the lobulation of the structure is revealed only by the end of the first year of life, it is full-blooded, as a result of which it rapidly increases in size in various pathologies, especially in infectious diseases and intoxications. By the age of 8, the morphological and histological structure of the liver is the same as in adults.

The liver performs various and very important functions: 1) produces bile, which is involved in intestinal digestion, stimulates the motor activity of the intestine and sanitizes its contents; 2) deposits nutrients, mainly an excess of glycogen; 3) carries out a barrier function, protecting the body from exogenous and endogenous pathogenic substances, toxins, poisons, and takes part in the metabolism of medicinal substances; 4) participates in the metabolism and transformation of vitamins A, D, C, B12, K; 5) during intrauterine development is a hematopoietic organ.

The functional capacity of the liver in young children is relatively low. Its enzyme system is especially inconsistent in newborns. In particular, the metabolism of indirect bilirubin released during hemolysis of erythrocytes is incomplete, resulting in physiological jaundice.

The gallbladder.In newborns, the gallbladder is located deep in the thickness of the liver and has a fusiform shape, its length is about 3 cm.

it acquires a piquant pear-shaped form by 6-7 months and reaches the edge of the liver by 2 years.

The bile of children is different in composition from the bile of adults. It is poor in bile acids, cholesterol and salts, but rich in water, mucin, pigments, and in the neonatal period, in addition, urea. A characteristic and favorable feature of the child's bile is the predominance of taurocholic acid over glycocholic acid, since taurocholic acid enhances the bactericidal effect of bile, and also accelerates the separation of pancreatic juice. Bile emulsifies fats, dissolves fatty acids, improves peristalsis.

Intestines.In children, the intestine is relatively longer than in adults (in an infant it exceeds the body length by 6 times, in adults - by 4 times), but its absolute length individually varies within wide limits. The cecum and appendix are mobile, the latter is often located atypically, thereby complicating the diagnosis of inflammation. The sigmoid colon is relatively longer than in adults, and even forms loops in some children, which contributes to the development of primary constipation. With age, these anatomical features disappear. In connection with the weak fixation of the mucous and submucosal membranes of the rectum, its prolapse is possible with persistent constipation and tenesmus in weak children. The mesentery is longer and easily stretchable, and therefore easily torsion, intussusception, etc. The omentum in children under 5 years of age is short, so the possibility of localization of peritonitis in a limited area of \u200b\u200bthe abdominal cavity is almost excluded. Of the histological features, it should be noted the good expression of the villi and the abundance of small lymphatic follicles.

All intestinal functions (digestive, absorption, barrier and motor) in children differ from those of adults. The digestion process, which begins in the mouth and stomach, continues in the small intestine under the influence of pancreatic juice and bile secreted into the duodenum, as well as intestinal juice. The intestinal secretory apparatus at the time of the birth of the child is generally formed, and even in the smallest children, the same enzymes are determined in the intestinal juice as in adults (enterokinase, alkaline phosphatase, erepsin, lipase, amylase, maltase, lactase, nuclease), but significantly less active. Only mucus is secreted in the large intestine. Under the influence of intestinal enzymes, mainly of the pancreas, the breakdown of proteins, fats and carbohydrates occurs. The process of digestion of fats is especially intense due to the low activity of lipolytic enzymes.

In breastfed babies, bile-emulsified lipids are broken down by 50% under the influence of breast milk lipase. Digestion of carbohydrates occurs in the small intestine parietally under the influence of pancreatic juice amylase and 6 disaccharidases localized in the brush border of enterocytes. In healthy children, only a small part of the sugars does not undergo enzymatic breakdown and is converted into lactic acid in the large intestine by bacterial decomposition (fermentation). Putrefaction processes in the intestines of healthy infants do not occur. The products of hydrolysis, formed as a result of cavity and parietal digestion, are absorbed mainly in the small intestine: glucose and amino acids into the blood, glycerol and fatty acids into the lymph. In this case, both passive mechanisms (diffusion, osmosis) and active transport with the help of carrier substances play a role.

The structural features of the intestinal wall and its large area determine in young children a higher absorption capacity than in adults and, at the same time, an insufficient barrier function due to the high permeability of the mucous membrane for toxins, microbes and other pathogenic factors. The components of human milk are most easily absorbed, the protein and fats of which in newborns are partially absorbed unbroken.

The motor (motor) function of the intestine is carried out in children very vigorously due to pendulum-like movements that stir food, and peristaltic, moving food to the exit. Active motor skills are reflected in the frequency of bowel movements. In infants, defecation occurs reflexively, in the first 2 weeks of life up to 3 - 6 times a day, then less often, by the end of the first year of life, it becomes an arbitrary act. In the first 2 to 3 days after birth, the child secretes meconium (original feces) of a greenish-black color. It consists of bile, epithelial cells, mucus, enzymes, and swallowed amniotic fluid. The feces of healthy newborns who are breastfed have a mushy consistency, a golden yellow color, and a sour odor. In older children, the chair is decorated, 1-2 times a day.

Microflora.During intrauterine development, the intestines of the fetus are sterile. Its colonization with microorganisms occurs first when the mother's birth canal passes, then through the mouth when children come into contact with surrounding objects. The stomach and duodenum contain scarce bacterial flora. In the small and especially the large intestine, it becomes more diverse, the number of microbes increases; microbial flora depends mainly on the type of feeding of the child. When feeding with breast milk, the main flora is B. bifidum, the growth of which is promoted (betta-lactose of human milk. When complementary foods are introduced into the diet or the child is transferred to cow's milk feeding, Gram-negative Escherichia coli, which is a conditionally pathogenic microorganism, predominates in the intestine. thus, dyspepsia is more often observed in children on artificial feeding.According to modern concepts, the normal intestinal flora performs three main functions: 1) creating an immunological barrier; 2) final digestion of food debris and digestive enzymes; 3) synthesis of vitamins and enzymes. The normal composition of the intestinal microflora (eubiosis) is easily disturbed under the influence of infection, improper diet, as well as the irrational use of antibacterial agents and other drugs, leading to a state of intestinal dysbiosis.

During the growth and development of children, the digestive system undergoes significant changes.

In children of the first months of life oral cavity relatively small, well-developed chewing muscles, large tongue. The mucous membrane of the oral cavity is delicate, rich in blood vessels.

Salivary glands function from the moment of birth, but saliva secretion there is little, which causes dryness of the oral mucosa and its frequent injury. At an early age, the production of secretory immunoglobulin A by the salivary glands is reduced. This is the cause of frequent stomatitis, mucosal candidiasis.From 4 to 6 months beginsprofuse salivation, which is associated with irritation of the trigeminal nerve teething teeth. After the introduction of complementary foods containing a large amount of starch, the value of the amylase activity of the salivary glands increases. By the age of 2 years, the structure of the salivary glands is similar to that of adults.

Esophagusin young children

- relatively longer than in adults,

- its mucous membrane is delicate,

- rich in blood vessels,

- dry, since the mucous glands are almost undeveloped,

- has a funnel-shaped shape with an expansion in its cardial part.

Stomach in children

- has a horizontal position,

- the location of the stomach varies with age:

when the child begins to walk, the stomach takes a more upright position,

The mucous membrane of the stomach is thicker than that of an adult,

The stomach is compared to “ open bottle”, Since the muscles of the stomach are moderately developed, the fundus and the cardiac part are poorly developed, and the pyloric part is functionally well developed, which is one

from the reasons for the frequent regurgitation of infants,

- the capacity of the stomach increases gradually: from 30-35 ml in a newborn,

by 3 months up to 100 ml,

by 1 year - 250 ml.

Secretory glands of the gastric mucosa (Coolant) secretes gastric juice, which contains all the enzymes (pepsin, lipase, rennet ...). It is due to the presence of gastric lipase and milk lipase that hydrolysis of breast milk fats occurs. In older children, in the process of digestion, 1.5-2 liters of gastric juice are formed during the day. The coolant has numerous folds, margins and dimples, which significantly increases its secretory surface. From the side of the stomach cavity, it is covered with a single-layer columnar epithelium. It forms insoluble mucus, which acts as a protective barrier against mechanical, thermal and chemical damage to the coolant.

The normal functioning of the digestive organs in children is of great importance for the development of the child, since indigestion contributes to metabolic and nutritional disorders.

The immaturity of the enzymatic systems, the great vulnerability of the gastrointestinal tract of children requires exceptional attention to the quality, quantity of food and the diet of children. It is no coincidence that in ancient times the gastrointestinal tract was called the "factory of life."

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