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Stomach and intestines - Diseases of digestive organs at children

Table of contents
Diseases of digestive organs at children
Oral cavity
Diseases of teeth
Malformations of the sky and soft tissues of an oral cavity
Diseases of a mucous membrane of an oral cavity and gums
Diseases of lips and language
Sialadens
Digestive tract
Basic reasons of gastrointestinal frustration
Gullet
Atresia and esophageal and tracheal fistula
Guttural and tracheal and esophageal crevice, inborn stenosis of a gullet
Other diseases of a gullet
Stomach and intestines
Peptic ulcer
Inborn hypertrophic pyloric stenosis
Inborn impassability of intestines
Inborn impassability of a duodenum
Disturbances of turn of intestines
Inborn impassability of a small bowel
Inborn megacolon
Diverticulums and duplikatura
The acquired impassability of intestines
Intestines invagination
Foreign bodys of a stomach and intestines
Motive frustration. stomach and intestines
Anomalies of a structure of anorectal area
Infectious diseases of intestines
Nonspecific ulcer colitis
Illness Krone
Necrotic coloenteritis of newborns
The coloenteritis connected with treatment by antibiotics
Gastrointestinal symptoms of anaphylactoid purpura, gemolitiko-uraemic syndrome
Intolerance of food proteins
Eosinophilic gastroenteritis
Absorption disturbance syndromes
Malabsorption
Immunodeficiency and intestines
Syndrome of "a congestive loop"
Syndrome of a short small bowel
Gee's disease
Sprue after acute enteritis
Tropical to a spr
Whipple's illness, intestines lymphangiectasia, Uolmap's illness, idiopathic diffusion defeat of mucous
Enzymopathies and disturbances of mechanisms of transport of nutrients
Irritable colon
Acute appendicitis
Diseases of an anus, direct and large intestine
Tumors of a digestive tract at children
Hernias of a digestive tract at children
Exocrine part of a pancreas
Pancreatitis
Embryonic development of structure and function of a liver
Diagnosis of diseases of a liver
Cholestatic states at babies
Parenchymatous jaundices at children of chest age
Disturbances of a metabolism of a liver and zhelchevydelitelny system
Anomalies of a structure of bilious ways
Cysts of bilious channels
Cholestasia and diseases of a liver connected with completely parenteral food
Medicinal damage of a liver
Ray's syndrome
Chronic hepatitis
Wilson's illness — Konovalova
Indian juvenile cirrhosis
Damages of a liver at chronic colitis
Cirrhosis and chronic liver failure
Portal hypertensia and varicosity of a gullet
Fatty infiltration of a liver
Cholecystitis
Peritoneum diseases
Peritonitis
Peritoneum hernias
NORMAL DEVELOPMENT, STRUCTURE AND PHYSIOLOGY OF THE STOMACH AND INTESTINES

Development. The macroscopic and microscopic structure of a digestive tube begins to form at rather early stages of an antenatal life. By the beginning of the 4th week at a 3-millimetric embryo a front and back gut connect, forming a simple tube which turns counterclockwise around an umbilical artery. At this time the stomach and a caecum are formed. On the 8th week the caudal end of a tube connects to a rectum. The last forms from a foul place. On the 10th week the intestinal tube falls to an abdominal cavity again. Later the large intestine is extended, acquiring mature structure. The majority of anomalies of a structure arises at a delay or disturbance of these consecutive stages of development.
The muscles of peloric department of a stomach are visible on the 3rd month of an antenatal life, however even at the birth a muscular coat still relatively thin. Covering and main cells appear on the 14th week of pre-natal development. Cells of intestinal type in a mucous membrane of a stomach gradually disappear. Rather mature fibers in intestines are found by 12th week, and on the 20th week of a crypt become deep, on a cylindrical epithelium of intestines rather rare microvillis appear. Blood vessels and neuroplexes of a digestive tract completely form already to 12 — the 13th week. Intramural a ganglion appear in the beginning on the head end so if their development is late, then it affects a functional condition of distal departments. On the 8th week the intestinal tube begins to peristaltirovat, but become coordinated the movements of intestines shortly before the child's birth. Peyerova plaques form on the 20th week.

Fig. 12-9. Pre-and postnatalyiy development of activity of disaccharidases in the person. The lactase activity is shown rather late during pre-natal development and there is a pas low level at adults. (From: Aurichio S. et al.: Pediatrics 35:994, 1965.)
Пре- и постнатальиое развитие активности дисахаридаз у человека.

In general it is possible to tell that the digestive tract has rather mature structure even at strongly premature child. Functions of intestines also develop at early stages, however unlike structure they continue to form also after the birth. For example, secretion of a gastric juice sharply increases right after the birth, reaching peak by 10th day, and then (by 30th day) gradually decreases. Reaction of a stomach to stimulators of secretory function, apparently, remains low approximately to 3-month age when it reaches the lower limit of secretion of the healthy adult. The maximum pepsinia is directly proportional to products of hydrochloric acid. Development of an internal factor slowly grows during the first 2 weeks of life, and products of gastrin at newborns for the unclear reason are 2 — 3 times higher, than at adults.
Functional development of a small bowel also continues in the post-natal period. Glucose transport through an epithelium of a jejunum is found on the 20th week of pre-natal development, however the level of intensity of this process characteristic of adults is reached only in many years. Activity of disaccharidases is revealed at a 12-week fruit; activity of invertase and maltase reaches a maximum by 24th and 32nd week respectively; the lactase activity is shown later, reaching a maximum by 36th week (fig. 12-9). At many children who are especially belonging to negroid and Mongoloid race, the lactase activity of intestines falls by 3rd year of life.
Intestines of a fruit participate in a daily circulation of a large amount of amniotic liquid; considerable activity On + - To +-Atfazy is shown on the 10th week of pre-natal development. Thus, liquid transport through an intestinal wall (the main pathogenetic factor at diarrhea) at the premature children who were born in time and even proceeds adequately, but on a limit of functionality. Therefore diseases of a small bowel at the most small children proceed with heavy functional frustration while at children of advanced age function of intestines is more kept. It should be noted, however, that at the children of advanced age who are especially belonging to negroid and Mongoloid race, a thicket the lactose intolerance is observed, contained in foodstuff.
Absorption of fats at premature children is lower, than at been born in time, and at the last below, than at more senior children. It is explained by the low level of synthesis and transport of salts of bile acids in the first year of life.
In the first days of life the digestive tract passes a small amount of intact proteins. Passing of proteinaceous antigens through a mucous membrane can play further the defined role in development of a food or microbic allergy.
Normal structure. Walls of bodies of a digestive tract consist of several layers; each layer carries out important function and can be exposed to pathological changes. The serous cover represents a visceral peritoneum which covers a stomach and intestines up to a rectum. The muscular coat consists of 2 layers: outside, with longwise the located fibers, and internal, circular. In a large intestine longitudinal fibers gather in bunches, or teniya. The submucosa serves as a bed for lymphatic and vascular textures, contains lymphoid cells and macrophages, and in a duodenum — gland brunnerova. The structure of a mucous membrane of a small bowel corresponds to its function — to soak up nutrients: the set of constantly moving, acting in a gleam of a gut fibers have the total surface equal on the area to a tennis court. Children have these fibers of a leaflike form unlike a finger-shaped form at adults. Therefore it is possible to consider that the functional surface of a small bowel increases with age. A mucous membrane of a large intestine flat, with the multiple tubular crypts opening on a surface. The mucous membrane of a rectum is maleficiated. Own plate — the cellular layer lying under an epithelium — contains phagocytes and cells which cosecrete immunoglobulins. It forms a connective tissue basis for an epithelium and its vessels. The adenoid tissue is concentrated in peyerovy plaques which quantity increases in distal part of a small bowel. Cells of a cylindrical epithelium of a small bowel divide into 4 look. The bulk is made by the absorbing cells which are carrying out difficult function of nutritive absorption. Scyphoid cells cosecrete mainly slime, and endocrine cells — certain intestinal hormones. In crypts there are Panet's cells which function is unknown. On the gut of a surface of the absorbing cells turned to a gleam there are microvillis, the so-called "brush border" covered with a glycocalyx. The differentiation of enterocytes occurs in crypts. The absorbing cells ripen in process of migration to fiber top from where they are torn away in a gut cavity. The epithelium of a jejunum is updated in only 5 — 6 days; therefore it is quickly recovered after damage, but at babies this process is slowed a little down. The epithelium over peyerovy plaques has no fibers and contains special M-cells which, apparently, distinguish antigens. The cylindrical epithelium of a large intestine differs from enteric in the fact that its mikrovorsipk are shorter and is small it. The lowermost site of a rectum 2 cm long is covered with a multilayer flat epithelium.

Normal function. The stomach represents the reservoir, from the food which liquefied, mixed, but a little digested comes to intestines. Besides, the stomach cosecretes the internal factor necessary for assimilation of vitamin of Vee in an ileal gut.
In a small bowel not only nutrients and sawn-off epithelial cells are processed, but also large volume of liquid is soaked up. At adults the volume of the soaked-up liquid at least by 7 times exceeds the volume of the drunk liquid.
Intracavitary digestion depends generally on exocrine function of a pancreas. Synthesis, and also secretion of bicarbonates and digestive enzymes are stimulated with secretin and cholecystokinin. They are developed by a mucous membrane of upper part of a small bowel in response to various incentives proceeding from an intestines cavity; in particular, such effect is rendered by some components of food. Splitting of components of food — the intensive and fast process which is usually coming to the end in the most proximal segment of a small bowel. On a surface of microvillis of sugar and starch get already split to di - and monosaccharides, squirrels — to peptides and amino acids, triglycerides — to monoglycerides and fatty acids. An important role is played by the salts of bile acids facilitating process of digestion and promoting contact of feedstuffs with the soaking-up epithelium surface. Digestion is also promoted by emulsification of fats at which monoglycerides with a long chain and fatty acids form the micelles mixed with bilious salts and phospholipids and in such look Reach an epithelium. Absorption of sterols, for example vitamin D, especially depends on formation of micelles therefore such diseases as an atresia of bilious ways, negatively influence vitamin D assimilation. It should be noted, however, that the triglycerides with average chains which are a part of some special medical diets can be acquired without formation of micelles, emulsification or hydrolysis.
Carbohydrates, proteins and fats are normal soaked up in upper part of a small bowel, though the distal segment possesses high absorbtsiopny ability. Sodium, potassium, chlorides and water are also soaked up generally in a small bowel. Salts of bile acids and B12 vitamin are selectively soaked up in distal part of an ileal gut, and iron — in a duodenum and proximal part of a jejunum. In general metabolic and transport functions of an intestinal epithelium are more actively carried out on a surface of fibers, than in crypts.
Disaccharides are split by the specific disaccharidases which are on the outer side of microvillis. The monosaccharides which are formed at the same time actively are transported through a cell and get to portal system. Dipeptides and peptides of the bigger size are hydrolyzed on a brush border, but can get into a cell not changed (before they are affected by peptidases). In a small bowel there are mechanisms for active transport of specific groups of amino acids, similar to those which work in renal tubules. Monoglycerides and fatty acids get into an epithelium intact; in cells there is a resynthesis of triglycerides which together with phospholipids and lipoproteids form chylomicrons. The last then come to a lymphatic bed. As triglycerides with average chains (unlike triglycerides with long chains) can pass through an epithelium and get into portal system in an intact look, these specially prepared dietary fats with success apply to treatment of patients at whom absorption of fats is broken.
Intake of sodium (in a complex with the proteinaceous carrier) through a brush border in cells of an epithelium is facilitated in the presence of glucose, but there is also other mechanism of digestion of sodium — the "sodium pompe" located in a basolateral cell membrane and connected with activity of Na+-K+-ATФазы.
The main function of a large intestine consists in further absorption of water which promotes consolidation of fecal masses. Kal collects in a rectum until its stretching does not excite a defecation reflex which in combination with any relaxation of an outside sfpnkter provides evacuation of fecal masses.
 



 
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