Age features of the endocrine system and puberty. Anatomical and physiological features of the endocrine system in children of different ages

Endocrine systemsis the main regulator of growth and development of the body. The endocrine system includes: pituitary, pineal, thyroid, pancreas, parathyroid, thymus, gonads, adrenal glands. Some endocrine glands start to function during embryonic development. A significant influence on the growth and development of the child is exerted by the hormones of the mother's body, which he receives in the prenatal period and with breast milk. IN different periods childhood, the relative predominant influence of one particular endocrine gland can be detected. For example, 5-6 months the thyroid gland begins to function intensively, the leading role of which remains up to 2-2.5 years. The action of the anterior pituitary gland becomes especially noticeable in children 6-7 years old. In pre puberty the functional activity of the thyroid gland and pituitary gland increases. In the prepubertal and especially in the pubertal period, the main influence on the growth and development of the body is exerted by the hormones of the gonads. Pituitary. This is an endocrine gland, on the activity of which the structure and functions of the thyroid gland, adrenal glands, and gonads largely depend. By the time of birth, the pituitary gland has a distinct secretory activity. Hyperfunction of the anterior pituitary gland affects growth and leads to pituitary gigantism, and at the end of the growth period, to acromegaly. Hypofunction causes pituitary dwarfism (dwarfism). Insufficient secretion of gonadotropic hormones is accompanied by a delay in pubertal development. An increase in the function of the posterior pituitary gland leads to a violation of fat metabolism with a delay in puberty. With insufficient production of antidiuretic hormone, diabetes insipidus develops. Epiphysis (pineal gland).In children, it is larger than in adults, produces hormones that affect the sexual cycle, lactation, carbohydrate and water-electrolyte metabolism. Thyroid.In newborns, it has an unfinished structure. Its weight at birth is 1-5 g. Until the age of 5-6 years, the formation and differentiation of the parenchyma, an intensive increase in the mass of the gland is noted. A new peak in the growth of the size and mass of the gland occurs during puberty. The main hormones of the gland are thyroxine, triiodothyronine (T3, T4), thyrocalcitonin. The function of the thyroid gland is controlled by the hormones of the pituitary gland and the adrenal medulla (by the mechanism feedback). Hormones T3 and T4 are the main stimulators of metabolism, growth and development of the body. Insufficiency of thyroid function in the fetus may not affect its development, since the placenta passes maternal thyroid hormones well.

Parathyroid glands.They are smaller in children than in adults. In the glands, parathyroid hormone is synthesized, which, together with vitamin D important in the regulation of phosphorus calcium metabolism. Function deficiency parathyroid glands in the first weeks of a child's life leads to neonatal hypocalcemia, more common in preterm infants. Thymus gland (thymus). In newborns and young children, it has a relatively large mass. Its maximum development occurs up to 2 years, then the gradual involution of the gland begins. As the central organ of immunity, the thymus forms a population of T-lymphocytes that carry out the reaction of cellular immunity. Premature involution of the thymus gland is accompanied in children by a tendency to infectious diseases, lagging behindneuropsychic and physical development. The activity of the thymus is associated with the activation of growth and inhibition of the function of the sex glands, adrenal glands and thyroid gland. Participation of the thymus gland in the control of the state of carbohydrate and calcium metabolism, neuromuscular transmission of impulses has been established. Adrenals. In newborns, the adrenal glands are larger than in adults. Their medulla in young children is underdeveloped, the restructuring and differentiation of its elements ends by 2 years. The cortical substance produces more than 60 biologically active substances and hormones, which, according to their effect on metabolic processes, are divided into glucocorticoids, mineralocorticoids, androgens and estrogens. Glucocorticoids regulate carbohydrate metabolism, have a pronounced anti-inflammatory and hyposensitizing effect. Mineralocorticoids are involved in the regulation water-salt metabolism and carbohydrate metabolism. Functionally, the adrenal cortex is closely related to ACTH, sex and other endocrine glands. The hormones of the medulla - adrenaline and norepinephrine - affect the level of blood pressure. In newborns and infants the adrenal cortex produces all the corticosteroids necessary for the body, but their total excretion in the urine is low. A decrease in adrenal function is possible in children with lymphatic-hypoplastic diathesis, with toxic effects, hemorrhages, tumor processes, tuberculosis, severe dystrophy. One form of dysfunction is acute adrenal insufficiency. Pancreas. This gland has exocrine and intrasecretory functions. Its mass in newborns is 4-5 g, by the period of puberty it increases 15-20 times. Pancreatic hormones are synthesized in the islets of Langerhans: β-cells produce insulin, α-cells produce glucagon. By the time of the birth of a child, the hormonal apparatus of the pancreas is anatomically developed and has sufficient secretory activity. endocrine function pancreas is closely related to the action of the pituitary, thyroid, adrenal glands. Important role in its regulation belongs to the nervous system. Insufficient production of insulin leads to the development of diabetes mellitus. Sex glands. These include the ovaries and testicles. These glands begin to function intensively only by the period of puberty. Sex hormones have a pronounced effect on the growth and development of the genital organs, cause the formation of secondary sexual characteristics.

The endocrine system in children regulates the functions of cells, tissues and organs in the process of human life.

Each age has its own level endocrine regulation. Under normal conditions of development of the child, a special hormonal activation of the trophic function, intensive growth and tissue differentiation occur in each period.

Under unfavorable living conditions, the child turns off the mechanisms of endocrine compensation that help overcome the influence of the environment. insufficient function endocrine glands under unfavorable conditions, it can lead to a breakdown of the reactions of the adaptation.

The central link of endocrine regulation in humans is the hypothalamus. Hypothalamic hormones are referred to as "releasing hormone" (RH) or "releasing factor" (RF). Releasing hormones regulate the activity of the pituitary gland. The pituitary gland consists of three lobes - anterior, middle and posterior. In the anterior lobe, 6 hormones are formed: ACTH (adenocorticotropic), STH (somatotropic), TSH (thyroid-stimulating), FSH (follicle-stimulating), LH (luteinizing), LTH (lactogenic or prolactin). In the middle, or intermediate, share, the melanoform hormone is formed. The posterior lobe (neurohypophysis) produces oxytocin and vasopressin (antidiuretic hormone).

Pituitary hormones regulate the activity of the endocrine glands: thyroid, parathyroid, genital, adrenal, pancreatic islets.

The thyroid gland in newborns has a mass of 1-5 g. By the age of 5-6, the mass of the gland increases to 5.3 g, and by the age of 14 - up to 14.2 g. With age, the size of the nodules in the gland increases, the content of the colloid increases, the number of follicles increases . The final histological maturation of the thyroid gland occurs by the age of 15.

The main thyroid hormones are thyroxine and triiodothyronine (T4 and T3). It also produces thyrocalcitonin. These hormones influence growth, skeletal maturation, brain differentiation, and intellectual development, the development of skin structures and its appendages, the regulation of oxygen consumption by tissues, the use of carbohydrates and amino acids in tissues. Thus, thyroid hormones are universal stimulators of metabolism, growth and development of the child.

The pancreas performs exocrine and endocrine functions. The endocrine function of the pancreas is associated with the activity of islet cells. Glucagon is produced by α-cells, insulin - by β-cells. After the differentiation of the islets, already after birth, ∆-cells producing somatostatin are found in the pancreas.

Insulin is involved in the regulation of glucose. Glucagon, on the other hand, raises blood glucose levels. Somatostatin is involved in the regulation of growth and development of the child.

The parathyroid glands in a newborn have a mass of 5 mg, by the age of 10 it reaches 40 mg, in an adult - 75-85 mg. There are usually 4 or more parathyroid glands. In general, after birth, the function of the parathyroid glands gradually decreases. Their maximum activity is observed in the perinatal period and at 1-2 years of age. They affect osteogenesis and tension of phosphorus-calcium metabolism. Parathyroid hormone - parathormone - together with vitamin D regulates calcium absorption from the intestine, calcium reabsorption in the kidney tubules and calcium leaching from bones, activates bone osteoclasts.

With hypoparathyroidism, the calcium content in the blood in children is reduced to 0.9-1.2 mmol/l, and the phosphorus content is increased to 3.0-3.2 mmol/l. In hyperparathyroidism, on the contrary, the level of calcium in the blood is increased to 3-4 mmol/l, and the content of phosphorus is reduced to 0.8 mmol/l. Clinically, convulsions (spastic seizures), including febrile ones, a tendency to unstable or loose stools, late eruption and early destruction of teeth, and increased neuromuscular excitability are noted clinically.

With hyperparathyroidism, muscle weakness, constipation, bone pain, bone fractures, and the formation of calcifications in the kidneys are determined.

Adrenals - paired organ. The adrenal tissue consists of two layers: cortical and medulla. The mass and size of the adrenal glands depend on the age of the child. In a newborn, the adrenal gland is approximately 1/3 the size of a kidney. The adrenal gland differs in structure from a similar organ in adults. In newborns, the cortical zone is relatively wider and more massive and consists of many cells with a large number of mitoses. The final formation of the cortical layer ends by 10-12 years.

During childbirth, the baby receives from the mother a large number of adrenal hormones - corticosteroids. Therefore, he suppressed adrenocorticotropic function of the adrenal glands. In the first days after birth, metabolites of maternal hormones are actively excreted in the urine. And by the fourth day there is a decrease in both excretion and production of corticosteroids. Therefore, the child may develop signs of adrenal insufficiency before the 10th day. With age, the function of secreting adrenal hormones is activated.

In acute adrenal insufficiency in children, blood pressure drops, shortness of breath develops, a thready pulse develops, vomiting occurs (sometimes multiple), loose stools, a sharp decline tendon reflexes. In the blood of such children, the level of potassium increases (up to 24-45 mmol / l), the level of sodium and chlorine decreases. The leading role in this syndrome belongs to mineralocorticoids, although there is also overall decline all adrenal hormones.

In chronic adrenal insufficiency, there may be a lack of production of the hormones cortisol or aldosterone.

With a lack of cortisol, an inability to resist gradually develops. stressful situations, tendency to vasomotor collapse; there are attacks of hypoglycemia, up to convulsions; muscle weakness, feelings of fatigue, refusal to play, predisposition to respiratory disorders, recurrence of skin (rash) or respiratory (bronchospasm) allergic reactions; there is a wave of acute or exacerbation of chronic foci of infection; are celebrated accelerated growth tonsils or adenoids; subfebrile condition; blood lymphocytosis and eosinophilia.

With a lack of aldosterone production, there are arterial hypotension, vomiting, diarrhea, decreased weight gain, dehydration, muscle weakness. In the blood, hyponatremia, hyperkalemia, acidosis, and an increase in hematocrit are determined.

In chronic insufficiency of the adrenal cortex (hypocorticism), a change in the skin appears in the form of pigmentation of a grayish-smoky, brown, bronze or black color, which captures the folds of the skin and its open areas of the skin (on the face and neck).

With hyperproduction of adrenal hormones, Cushing's syndrome develops. With it, obesity is observed mainly on the face and torso, while the arms and legs are thin.

Adrenogenital syndrome is characterized by a violation of the water and electrolyte balance (due to vomiting and diarrhea), a change in secondary sexual characteristics. In girls, these are the phenomena of masculinization (development of genital organs resembling the male type), in boys - signs of precocious puberty. Ultimately, these children experience premature cessation of growth.

Sex glands (testicles, ovaries) carry out a long process of sex formation in children up to the age of puberty. In the prenatal period, the laying of the male or female genotype occurs, which is formed by the neonatal period. In the future, the growth and development of the genital organs occur in accordance with their differentiation. In general, the period of childhood (before puberty) is characterized by high sensitivity hypothalamic centers to minimal levels of blood androgens. Due to this, the influence of the hypothalamus on the production of gonadotropic hormones is curbed.

The main centers for regulating the development of the child are probably located in the posterior hypothalamus and in the epiphysis. In children of all ages, this period falls on the same dates in terms of bone age and relatively close indicators in terms of achieved body weight, separately for boys and girls. Signs of sexual development and their sequence depend on the age of the children.

For girls:

9-10 years old - growth of the pelvic bones, rounding of the buttocks, slight raised nipples of the mammary glands;

10-11 years - dome-shaped raised mammary glands ("bud" stage), the appearance of pubic hair;

11-12 years - an increase in the external genitalia, a change in the epithelium of the vagina;

12-13 years - development of the glandular tissue of the mammary glands and areas adjacent to the areola, pigmentation of the nipples, the appearance of the first menstruation;

14-15 years - change in the shape of the buttocks and pelvis;

15-16 years - the appearance of regular menstruation;

16-17 years - stop the growth of the skeleton.

The restructuring of the external genital organs is accompanied by changes in the internal genital organs - the vagina, uterus, ovaries.

For boys:

10-11 years - the beginning of the growth of the testicles and penis;

11-12 years - increase prostate, the growth of the larynx;

12-13 years old - significant growth of the testicles and penis, thickening of the peripapillary region, the beginning of voice changes;

14-15 years - hair growth in the armpits, further change voices, appearance of facial hair, pigmentation of the scrotum, first ejaculations;

15-16 years - maturation of spermatozoa;

16-17 years old - male-type pubic hair growth, hair growth throughout the body, the appearance of mature spermatozoa;

17-21 years - stop the growth of the skeleton.

The most controllable signs may be the size of the testicles and penis. The testicles are measured with an orchidometer, the penis with a centimeter tape.

The study of sex and puberty is a medical procedure. Secondary sexual characteristics are taken into account in points, taking into account the stages of development. At the same time, in girls, the abbreviation Ma 0, 1, 2, 3 determines the stage of development of the mammary glands; the development of hair in the armpits is designated as Ax o, 1, 2, 3, 4; the formation of the menstrual function is designated as Me 0, 1, 2, h. In boys, armpit hair is designated as Ax 0, 1, 2, 3, 4, pubic hair - as P 0, 1, 2, 3, 4, 5; growth of thyroid cartilage - L 0, 1, 2; facial hair - F 0, 1, 2, 3, 4, 5.

Examination of the child's genitals must be carried out in the presence of parents.

Hormonal balance in the human body has a great influence on the nature of its higher nervous activity. There is not a single function in the body that would not be under the influence of the endocrine system, at the same time, the endocrine glands themselves are influenced nervous system. Thus, in the body there is a single neuro-hormonal regulation of its vital activity.

Modern physiology data show that most hormones are able to change the functional state nerve cells in all parts of the nervous system. For example, adrenal hormones significantly change the strength nervous processes. Removal of some parts of the adrenal glands in animals is accompanied by a weakening of the processes of internal inhibition and excitation processes, which causes profound disturbances of all higher nervous activity. Pituitary hormones in small doses increase higher nervous activity, and in large doses they depress it. Thyroid hormones in small doses enhance the processes of inhibition and excitation, and in large doses they weaken the main nervous processes. It is also known that hyper- or hypofunction of the thyroid gland causes gross violations of the higher nervous activity of a person.
Significant impact on processes excitation and inhibition and the performance of nerve cells is provided by sex hormones. Removal of the gonads in a person or their pathological underdevelopment causes a weakening of the nervous processes and significant mental disorders. Castration ~ in childhood often leads to mental disability. It is shown that in girls during the onset of menstruation, the processes of internal inhibition are weakened, the formation of conditioned reflexes worsens, the level of general working capacity and school performance is significantly reduced. Especially numerous examples of the influence of the endocrine sphere on the mental activity of children and adolescents are given by the clinic. Damage to the hypothalamic-pituitary system and violation of its functions are most often found in adolescence and are characterized by disorders of the emotional-volitional sphere and moral and ethical deviations. Adolescents become rude, vicious, with a propensity for theft and vagrancy; increased sexuality is often observed (L. O. Badalyan, 1975).
All of the above indicates the huge role that hormones play in human life. A negligible amount of them is already able to change our mood, memory, performance, etc. With a favorable hormonal background“a person who seemed so lethargic, depressed, untalkative, complaining about his weakness and inability to think ... - wrote V. M. Bekhterev at the beginning of our century, - becomes vigorous and animated, works hard, creates various plans for his upcoming activities , declaring his excellent health, and the like.
Thus, the connection of the nervous and endocrine regulatory systems, their harmonious unity are a necessary condition for the normal physical and mental development of children and adolescents.

puberty begins in girls from 8-9 years old, and in boys from 10-11 years old and ends, respectively, at 16-17 and 17-18 years old. Its beginning is manifested in the increased growth of the genital organs. The degree of sexual development is easily determined by the totality of secondary sexual characteristics: the development of pubic hair and in armpit, in young men - also on the face; in addition, in girls - according to the development of the mammary glands and the time of the onset of menstruation.

Sexual development of girls. In girls, puberty begins at the early school age, from 8-9 years old. Of great importance for the regulation of the process of puberty are the sex hormones that are formed in the female sex glands - the ovaries (see section 3.4.3). By the age of 10, the mass of one ovary reaches 2 g, and by the age of 14-15 - 4-6 g, i.e., it practically reaches the mass of the ovary adult woman(5-6 g). Accordingly, the formation of female sex hormones in the ovaries is enhanced, which have a general and specific effect on the girl's body. The overall effect is associated with the influence of hormones on metabolism and developmental processes in general. Under their influence, there is an acceleration of body growth, development of bone and muscular systems, internal organs etc. The specific action of sex hormones is aimed at the development of the genital organs and secondary sexual characteristics, which include: anatomical features of the body, features hairline, voice features, development mammary glands, sexual attraction to the opposite sex, features of behavior and psyche.
In girls, an increase in the mammary or mammary glands begins at 10-11 years old, and their development ends by 14-15 years. The second sign of sexual development is the process of pubic hair growth, which manifests itself at 11-12 years of age and reaches its final development at 14-15 years of age. The third main sign of sexual development - armpit hair growth - manifests itself at 12-13 years of age and reaches its maximum development at 15-16 years of age. Finally, the first menstruation, or menstrual bleeding, begins in girls at an average of 13 years of age. Menstrual bleeding is the final stage of the cycle of development in the ovaries of the egg and its subsequent excretion from the body. Usually this cycle is 28 days, but there are menstrual cycles of a different duration: 21, 32 days, etc. does not require medical intervention. TO serious violations should be attributed to the absence of menstruation up to 15 years in the presence of excessive body hair or complete absence signs of sexual development, as well as sharp and heavy bleeding lasting more than 7 days.
With the onset of menstruation, the growth rate of the body in length in girls is sharply reduced. In subsequent years up to 15-16 years goes by the final formation of secondary sexual characteristics and the development of the female body type, the growth of the body in length practically stops.
Sexual development of boys. Puberty in boys occurs 1-2 years later than in girls. The intensive development of the genital organs and secondary sexual characteristics in them begins at the age of 10-11 years. First of all, the size of the testicles, paired male sex glands, in which the formation of male sex hormones, which also have a general and specific effect, is rapidly increasing.
In boys, the first sign indicating the onset of sexual development should be considered “voice breaking” (mutation), which is observed most often from 11–12 to 15–16 years of age. The manifestation of the second sign of puberty - pubic hair - is observed from 12-13 years. The third sign is an increase thyroid cartilage larynx (Adam's apple) - manifests itself from 13 to 17 years. And finally, last of all, from 14 to 17 years old, there is hair growth of the armpit and face. In some adolescents at the age of 17, secondary sexual characteristics have not yet reached their final development, and it continues in subsequent years.
At the age of 13-15 years, in the male gonads of boys, male germ cells begin to be produced - spermatozoa, the maturation of which, in contrast to the periodic maturation of eggs, occurs continuously. At this age, most boys have wet dreams - spontaneous ejaculation, which is a normal physiological phenomenon.
With the advent of wet dreams in boys, there is a sharp increase in growth rates - the "third stretching period", which slows down from the age of 15-16. About a year after the "growth spurt" there is a maximum increase in muscle strength.
The problem of sexual education of children and adolescents. With the onset of puberty in boys and girls, one more problem is added to all the difficulties of adolescence - the problem of their sexual education. Naturally, it should be started already at primary school age and be only an integral part of a single educational process. The outstanding teacher A. S. Makarenko wrote on this occasion that the issue of sexual education becomes difficult only when it is considered separately and when it is given too much importance, singling out from the general mass of other educational issues. It is necessary to form in children and adolescents the correct ideas about the essence of the processes of sexual development, to cultivate mutual respect between boys and girls and their correct relationships. It is important for adolescents to form the correct ideas about love and marriage, about the family, to acquaint them with the hygiene and physiology of sexual life.
Unfortunately, many teachers and parents try to "get away" from the issues of sex education. This fact is confirmed by pedagogical research, according to which more than half of children and adolescents learn about many "delicate" issues of their sexual development from their older comrades and girlfriends, about 20% from their parents and only 9% from teachers and educators.
Thus, sexual education of children and adolescents should be mandatory. integral part their upbringing in the family. The passivity of the school and parents in this matter, their mutual hope for each other, can only lead to the emergence of bad habits and misconceptions about the physiology of sexual development, about the relationship between men and women. It is possible that many of the difficulties of the subsequent family life newlyweds are due to defects in improper sex education or its absence altogether. At the same time, all the difficulties of this “delicate” topic, which requires teachers, educators and parents to have special knowledge, pedagogical and parental tact, and certain pedagogical skills, are quite understandable. In order to equip teachers and parents with all the necessary arsenal of means of sexual education in our country, special pedagogical and popular science literature is widely published.

Parathyroid (parathyroid) glands. These are the four smallest endocrine glands. Their total mass is only 0.1 g. They are located in the immediate vicinity of the thyroid gland, and sometimes in its tissue.

Parathormone- The parathyroid hormone plays a particularly important role in the development of the skeleton, as it regulates the deposition of calcium in the bones and the level of its concentration in the blood. A decrease in calcium in the blood, associated with hypofunction of the glands, causes an increase in the excitability of the nervous system, many disorders of autonomic functions and skeletal formation. Rarely occurring hyperfunction of the parathyroid glands causes decalcification of the skeleton ("softening of the bones") and its deformation.
Goiter (thymus) gland. The thymus gland consists of two lobes located behind the sternum. Its morphofunctional properties change significantly with age. From the moment of birth to puberty, its mass increases and reaches 35-40 g. Then the process of transformation of the goiter gland into adipose tissue is observed. So, for example, by the age of 70, its mass does not exceed 6 g.
The affiliation of the thymus to the endocrine system is still disputed, since its hormone has not been isolated. However, most scientists assume its existence and believe that this hormone affects the growth processes of the body, the formation of the skeleton and the immune properties of the body. There are also data on the influence of the thymus gland on the sexual development of adolescents. Its removal stimulates puberty, since it apparently has an inhibitory effect on sexual development. The connection of the thymus gland with the activity of the adrenal glands and the thyroid gland has also been proven.
Adrenals. These are paired glands weighing about 4-7 g each, located on the upper poles of the kidneys. Morphologically and functionally, two qualitatively different parts of the adrenal glands are distinguished. The upper, cortical layer, the adrenal cortex, synthesizes about eight physiologically active hormones- corticosteroids: glucocorticoids, mineralocorticoids, sex hormones - androgens (male hormones) and estrogens (female hormones).
Glucocorticoids in the body regulate protein, fat and especially carbohydrate metabolism, have an anti-inflammatory effect, increase the body's immune resistance. As shown by the work of the Canadian pathophysiologist G. Selye, glucocorticoids are important in ensuring the stability of the body in a state of stress. Especially their number increases in the stage of resistance of the organism, i.e., its adaptation to stressful influences. In this regard, it can be assumed that glucocorticoids play an important role in ensuring the full adaptation of children and adolescents to "school" stressful situations (coming to the 1st grade, moving to a new school, exams, tests, etc.).
Mineralocorticoids are involved in the regulation of mineral and water metabolism, among these hormones aldosterone is especially important.
Androgens and estrogens in their action they are close to the sex hormones synthesized in the gonads - the testes and ovaries, but their activity is much less. However, in the period before the full maturation of the testes and ovaries, androgens and estrogens play a decisive role in the hormonal regulation of sexual development.
The inner, medulla of the adrenal glands synthesizes extremely important hormone- adrenaline, which has a stimulating effect on most body functions. Its action is very close to the action of the sympathetic nervous system: it speeds up and enhances the activity of the heart, stimulates energy transformations in the body, increases the excitability of many receptors, etc. All these functional changes contribute to an increase in the overall performance of the body, especially in "emergency" situations.
Thus, adrenal hormones largely determine the course of puberty in children and adolescents, provide the necessary immune properties of the child and adult organism, participate in stress reactions, regulate protein, fat, carbohydrate, water and mineral metabolism. Adrenaline has a particularly strong effect on the vital activity of the body. An interesting fact is that the content of many adrenal hormones depends on the physical fitness of the child's body. A positive correlation has been found between the activity of the adrenal glands and the physical development of children and adolescents. Physical activity significantly increases the level of hormones that provide protective functions of the body, and thus contributes to optimal development.
The normal functioning of the body is possible only with the optimal ratio of the concentrations of various adrenal hormones in the blood, which is regulated by the pituitary gland and the nervous system. A significant increase or decrease in their concentration in pathological situations is characterized by violations of many body functions.
epiphysis The influence of the hormone of this gland, also located near the hypothalamus, on the sexual development of children and adolescents was found. Its damage causes premature puberty. It is assumed that the inhibitory effect of the pineal gland on sexual development is carried out through blocking the formation of gonadotropic hormones in the pituitary gland. In an adult, this gland practically does not function. However, there is a hypothesis that the pineal gland is related to the regulation of " biological rhythms» the human body.
Pancreas. This gland is located next to the stomach and duodenum. It belongs to mixed glands: pancreatic juice is formed here, which plays an important role in digestion, here the secretion of hormones involved in the regulation of carbohydrate metabolism (insulin and glucagon) is also carried out. One of endocrine diseases- diabetes mellitus - associated with pancreatic hypofunction. Diabetes mellitus is characterized by a decrease in the content of the hormone insulin in the blood, which leads to a violation of the absorption of sugar by the body and an increase in its concentration in the blood. In children, the manifestation of this disease is most often observed from 6 to 12 years. Hereditary predisposition and provoking environmental factors are important in the development of diabetes mellitus: infectious diseases, nerve strain and overeating. Glucagon, on the other hand, increases blood sugar levels and is therefore an insulin antagonist.
Sex glands. The gonads are also mixed. Here sex hormones are formed as sex cells. In the male gonads - the testes - male sex hormones - androgens are formed. A small amount of female sex hormones - estrogens - is also formed here. In the female sex glands - the ovaries - female sex hormones and a small amount of male hormones are formed.
Sex hormones largely determine the specific features of metabolism in the female and male organisms and the development of primary and secondary sexual characteristics in children and adolescents.
Pituitary. The pituitary gland is the most important endocrine gland. It is located in the immediate vicinity of the diencephalon and has numerous bilateral connections with it. Up to 100 thousand nerve fibers have been found that connect the pituitary gland and the diencephalon (hypothalamus). This close proximity of the pituitary gland and the brain is a favorable factor for combining the "efforts" of the nervous and endocrine systems in the regulation of the body's vital activity.
In an adult, the pituitary gland weighs about 0.5 g. At the time of birth, its mass does not exceed 0.1 g, but by the age of 10 it increases to 0.3 g and reaches the level of an adult in adolescence. In the pituitary gland, there are mainly two lobes: the anterior - adenohypophysis, which occupies about 75% of the size of the entire pituitary gland, and the posterior - non-Pro pituitary gland, which is about 18-23%. In children, an intermediate lobe of the pituitary gland is also isolated, but in adults it is practically absent (only 1-2%).
About 22 hormones are known, which are formed mainly in the adenohypophysis. These hormones - triple hormones - have a regulatory effect on the functions of other endocrine glands: thyroid, parathyroid, pancreas, genital and adrenal glands. They also influence all aspects of metabolism and energy, the processes of growth and development of children and adolescents. In particular, growth hormone (somatotropic hormone) is synthesized in the anterior pituitary gland, which regulates the growth processes of children and adolescents. In this regard, hyperfunction of the pituitary gland can lead to a sharp increase in the growth of children, causing hormonal gigantism, and hypofunction, on the contrary, leads to a significant growth retardation. Mental development while remaining at a normal level. Pituitary tonadotropic hormones (follicle-stimulating hormone - FSH, luteinizing hormone - LH, prolactin) regulate the development and function of the sex glands, therefore, increased secretion causes an acceleration of puberty in children and adolescents, and hypofunction of the pituitary gland delays sexual development. In particular, FSH regulates the maturation of eggs in the ovaries in women, and spermatogenesis in men. LH stimulates the development of the ovaries and testes and the formation of sex hormones in them. Prolactin plays an important role in the regulation of lactation in lactating women. Termination of the gonadotropic function of the pituitary gland due to pathological processes can lead to a complete cessation of sexual development.
The pituitary gland synthesizes a number of hormones that regulate the activity of other endocrine glands, such as adrenocorticotropic hormone (ACTH), which enhances the secretion of glucocorticoids, or thyroid-stimulating hormone, which enhances the secretion of thyroid hormones.
Previously, it was believed that the neurohypophysis produces the hormones vasopressin, which regulates blood circulation and water metabolism, and oxytocin, which increases uterine contraction during childbirth. However, recent data from endocrinology indicate that these hormones are the product of neurosecretion of the hypothalamus, from there they enter the neurohypophysis, which plays the role of a depot, and then into the blood.
The interconnected activity of the hypothalamus, pituitary gland and adrenal glands, which form a single functional system- hypothalamic-pituitary-adrenal system, functional value which is associated with the processes of adaptation of the organism to stressful influences.
As shown special studies G. Selye (1936), the body's resistance to the action of adverse factors primarily depends on the functional state of the hypothalamic-pituitary-adrenal system. It is she who ensures the mobilization of the body's defenses in stressful situations, which is manifested in the development of the so-called general adaptation syndrome.
Currently, there are three phases, or stages, of the general adaptation syndrome: "anxiety", "resistance" and "exhaustion". The stage of anxiety is characterized by activation of the hypothalamic-pituitary-adrenal system and is accompanied by increased secretion of ACTH, adrenaline and adaptive hormones (glucocorticoids), which leads to the mobilization of all energy reserves of the body. In the stage of resistance, an increase in the body's resistance to adverse effects is observed, which is associated with the transition of urgent adaptive changes to long-term ones, accompanied by functional and structural transformations in tissues and organs. As a result, the body's resistance to stress factors is ensured not by increased secretion of glucocorticoids and adrenaline, but by increasing tissue resistance. In particular, athletes observe such a long-term adaptation to large physical activity. With prolonged or frequent repeated exposure to stress factors, the development of the third phase, the phase of exhaustion, is possible. This stage is characterized sharp drop the body's resistance to stress, which is associated with impaired activity of the hypothalamic-pituitary-adrenal system. The functional state of the organism at this stage deteriorates, and further action of adverse factors can lead to its death.
It is interesting to note that the functional formation of the hypothalamic-pituitary-adrenal system in the process of ontogenesis largely depends on the motor activity of children and adolescents. In this regard, it must be remembered that physical education and sports contribute to the development of the adaptive capabilities of the child's body and are an important factor in maintaining and strengthening the health of the younger generation.

The endocrine system is the main regulator of growth and development of the body. It includes the pituitary, epiphysis, thyroid, parathyroid, pancreas, thymus, adrenal glands and gonads. Some of them are already functioning in utero. A huge influence on the growth and development of the child is exerted by the hormones of the mother's body, which he receives in utero and with mother's milk during breastfeeding.
noted different influence certain endocrine glands at certain age periods. The first intensively begins to function at the age of 5-6 months, the thyroid gland, the leading role of which is noted up to 2-2.5 years. By the age of 6-7, the action of the anterior pituitary gland increases. In the prepubertal period, there is an increased activity of the thyroid gland and pituitary gland. In the prepubertal and pubertal period, the main influence on the growth and development of the body is exerted by the hormones of the gonads.
Underlying diseases endocrine system there is a violation of the hormonal activity (hyper- or hypofunction) of individual or several endocrine glands, which may be due to genetic (in particular, chromosomal) disorders, inflammatory changes, circulatory disorders, immune disorders and etc.
The pituitary gland is one of the main glands of the endocrine system, which influences the structure and function of the thyroid gland, adrenal glands and gonads. The pituitary gland is divided into three lobes that produce certain hormones.
The anterior pituitary gland produces:

• somatotropic hormone - growth hormone, is involved in protein metabolism. A lack of this hormone leads to dwarfism, and an excess leads to gigantism;
• thyroid-stimulating hormone stimulates the growth and function of the thyroid gland, increases its
  secretory function, accumulation of iodine by the gland, synthesis and release of its hormones;
• adrenocorticotropic hormone affects the adrenal cortex, stimulates the production of corticosteroid hormones, regulates carbohydrate metabolism;
• gonadotropic hormones stimulate the functions of the sex glands;
• follicle-stimulating hormone stimulates the growth and maturation of follicles in women, in the male body it promotes the growth and development of seminiferous tubules and spermatogenesis;
• luteinizing hormone stimulates the production of male hormones (androgens) in men, promotes the formation of an egg and the process of its release from the ovaries;
• lactogenic hormone in women affects the mammary gland, promoting lactation, and in men - the growth of the prostate gland;
• melanoform hormone regulates the formation of pigment in the skin;
• lipotropic hormone stimulates the use of fat in the energy metabolism of the body.

• antidiuretic hormone (vasopressin) - regulates water metabolism in the body.

• oxytocin affects the level of blood pressure, sexual development, protein and fat metabolism, contraction of the uterine muscle during childbirth.

The parathyroid glands synthesize iarathormone, which, together with vitamin D, is of great importance in the regulation of phosphorus-calcium metabolism.
The thymus gland (thymus) actively functions up to 2 years, and then its reverse development (involution) gradually begins. It is located in the anterior-upper part of the mediastinum, just behind the sternum. The thymus is the central organ of immunity, in which T-lymphocytes are formed, which carry out the protective function of the body from infectious agents. The thymus gland produces the hormones thymosin, thymopoietin, thymic factor, etc. The activity of the thymus gland is closely related to the activity of the gonads, adrenal glands and the thyroid gland. The participation of the thymus gland in the control of the activity of carbohydrate and calcium metabolism, neuromuscular transmission of impulses has been proven.
adrenal glands
In the adrenal glands, two layers, or substances, are distinguished: cortical and medulla. Their functions are varied.
Corticosteroid hormones are formed in the cortical substance, among which the most important are:

• glucocorticoids (hydrocortisone, corticosterone) regulate carbohydrate, protein, fat metabolism, have a pronounced anti-inflammatory, anti-allergic and immunosuppressive effect, maintain blood pressure at a certain level, stimulate the production of of hydrochloric acid and pepsin in the stomach;
• mineralcorticoids (aldosterone) are involved in the regulation of water-salt metabolism and carbohydrate metabolism, increase vascular tone;
• androgens (male sex hormones) affect the formation of the external genitalia and secondary male sexual characteristics, enhance protein synthesis.

• P-cells produce insulin, which promotes the utilization of glucose in tissues, enhances the synthesis of proteins, fats, nucleic acids;
• a-cells produce glucagon, which stimulates the breakdown of glycogen in the liver, causing an increase in blood glucose levels;
• D-cells secrete somatostatin, which suppresses the secretion of essential hormones

Endocrine system in children

Pituitary

The pituitary gland develops from two separate primordia. One of them - an outgrowth of the ectodermal epithelium (Rathke's pocket) - is laid in the human embryo at the 4th week of intrauterine life, and the anterior and middle lobes that make up the adenohypophysis are subsequently formed from it. Another germ is an outgrowth of the interstitial brain, consisting of nerve cells, from which the posterior lobe, or neurohypophysis, is formed.

The pituitary gland begins to function very early. From the 9-10th week of intrauterine life, it is already possible to determine traces of ACTH. In newborns, the mass of the pituitary gland is 10-15 mg, and by the period of puberty it increases by about 2 times, reaching 20-35 mg. In an adult, the pituitary gland weighs 50-65 mg. The size of the pituitary gland increases with age, which is confirmed by an increase in the Turkish saddle on radiographs. The average size of the Turkish saddle in a newborn is 2.5 x 3 mm, by 1 year - 4x5 mm, and in an adult - 9x11 mm. There are 3 lobes in the pituitary gland: 1) anterior - adenohypophysis; 2) intermediate (glandular) and 3) posterior, or neurohypophysis Most (75%) of the pituitary gland is the adenohypophysis, the average share is 1-2%, and the posterior lobe is 18-23% of the total mass of the pituitary gland. In the adenohypophysis of newborns, basophils dominate, and often they are degranulated, which indicates a high functional activity. Pituitary cells gradually increase with age.

The anterior pituitary produces the following hormones:

1 ACTH (adrenocorticotropic hormone).

2 STH (somatotropic) 3. TSH (thyrotropic).

4 FSH (follicle stimulating).

5. L G (luteinizing)

6. LTG or MG (lactogenic - prolactin).

7. Gonadotropic.

In the middle, or intermediate, share, the melanophoric hormone is formed. In the posterior lobe, or neurohypophysis, two hormones are synthesized a) oxytocin and b) vasopressin or antidiuretic hormone.

Somatotropic hormone (GH) - growth hormone - through somatomedins affects metabolism, and, consequently, growth. The pituitary gland contains about 3-5 mg of growth hormone. STH increases protein synthesis and reduces the breakdown of amino acids, which affects the increase in protein reserves. STH inhibits at the same time the oxidation of carbohydrates in tissues. This action is also largely mediated through the pancreas. Along with the effect on protein metabolism, GH causes retention of phosphorus, sodium, potassium, and calcium. At the same time, the breakdown of fat increases, as evidenced by the increase in free fatty acids in the blood. All this leads to accelerated growth (Fig. 77)

Thyroid-stimulating hormone stimulates the growth and function of the thyroid gland, increases its secretory function, the accumulation of iodine by the gland, the synthesis and release of its hormones. TSH is released in the form of preparations for clinical use and is used to differentiate between primary and secondary hypothyroidism (myxedema).

Adrenocorticotropic hormone affects the adrenal cortex, the size of which after the introduction of ACTH can double within 4 days. Basically, this increase occurs due to internal zones. The glomerular zone is almost not involved in this process.

ACTH stimulates the synthesis and secretion of cortisol corticosterone glucocorticoids and does not affect the synthesis of aldosterone. With the introduction of ACTH, thymus atrophy, eosinopenia, hyperglycemia are noted. This action of ACTH is mediated through the adrenal gland. The gonadotropic action of the pituitary gland is expressed in an increase in the function of the sex glands.

Based on the functional activity of hormones, it develops clinical picture pituitary lesions, which can be classified as follows:

I. Diseases resulting from hyperactivity of the gland (gigantism, acromegaly)

II Diseases resulting from insufficiency of the gland (Simmonds' disease, nanism).

III Diseases in which there are no clinical manifestations of endocrinopathy (chromophobic adenoma).

In the clinic complex combined disorders are very common. A special position is occupied by the age of the patient, when certain disorders of the pituitary gland occur. For example, if hyperactivity of the adenohypophysis occurs in a child, then the patient has gigantism. If the disease begins in adulthood, when growth stops, then acromegaly develops.

In the first case, when there was no closure of the epiphyseal cartilages, there is a uniform acceleration of growth, but eventually acromegaly also joins.

Itsenko-Cushing's disease of pituitary origin is manifested as a result of excessive ACTH stimulation of the adrenal glands. Its characteristic features are obesity, plethora, acrocyanosis, a tendency to purpura, purple stripes on the abdomen, hirsutism, dystrophy of the reproductive system, hypertension, osteoporosis, and a tendency to hyperglycemia. Obesity due to Cushing's disease is characterized by excessive deposition of fat on the face (moon-shaped), trunk, neck, while the legs remain thin.

The second group of diseases associated with insufficiency of the gland includes hypopituitarism, in which the pituitary gland can be affected primarily or secondarily. In this case, there may be a decrease in the production of one or more pituitary hormones. If this syndrome occurs in children, it is manifested by growth retardation followed by dwarfism. At the same time, other endocrine glands are also affected. Of these, the sex glands are first involved in the process, then the thyroid gland and, subsequently, the adrenal cortex. Children develop myxedema with typical skin changes (dryness, mucous swelling), decreased reflexes and increased cholesterol levels, cold intolerance, and reduced sweating.

Adrenal insufficiency is manifested by weakness, inability to adapt to stressful influences and reduced resistance.

Simmonds disease- pituitary cachexia - is manifested by general exhaustion. The skin is wrinkled, dry, the hair is sparse. Basal metabolism and temperature are reduced, hypotension and hypoglycemia. Teeth decay and fall out.

At congenital forms dwarfism and infantilism children are born of normal height and body weight. Their growth usually continues for some time after birth. Usually, from 2 to 4 years, they begin to notice a lag in growth. The body has the usual proportions and symmetry. Bone and tooth development, epiphyseal cartilage closure, and puberty are inhibited. Characterized by an age-inappropriate senile appearance - progeria. The skin is wrinkled and forms folds. The distribution of fat is disturbed.

With damage to the posterior pituitary gland - the neurohypophysis, a syndrome of diabetes insipidus develops, in which a huge amount of water is lost in the urine, as the reabsorption of H 2 0 in the distal tubule of the nephron decreases. Due to unbearable thirst, patients constantly drink water. Polyuria and polydipsia (which is secondary, since the body seeks to compensate for hypovolemia) can also occur secondary to certain diseases (diabetes mellitus, chronic nephritis with compensatory polyuria, thyrotoxicosis). Diabetes insipidus can be primary due to a true deficiency in the production of antidiuretic hormone (ADH) or nephrogenic due to insufficient sensitivity of the epithelium of the distal nephron tubule to ADH.

For judgment about the functional state of the pituitary gland, in addition to clinical data, various laboratory indicators are also used. Currently, these are primarily direct radioimmunological methods for studying the levels of hormones in the blood of a child.

Growth hormone (GH) is found in the highest concentration in newborns. In a diagnostic study of the hormone, its basal level is determined (about 10 ng in 1 ml) and the level during sleep, when natural boost secretion of growth hormone. In addition, provocation of hormone release is used, creating moderate hypoglycemia with insulin administration. During sleep and when stimulated by insulin, the level of growth hormone increases by 2-5 times.

adrenocorticotropic hormone in the blood of a newborn is 12 - 40 nmol / l, then its level decreases sharply and at school age is 6-12 nmol / l

Thyroid-stimulating hormone in newborns is exceptionally high - 11 - 99 mcU / ml, in other age periods its concentration is 15 - 20 times lower and ranges from 0.6 to 6.3 μU / ml.

Luteinizing hormone in boys at a younger age has a concentration in the blood of about 3 - 9 mcU / ml and by the age of 14-15 increases to 10 - 20 mcU / ml. In girls, over the same age interval, the concentration of luteinizing hormone increases from 4-15 to 10-40 mcU/ml. Especially significant is the increase in the concentration of luteinizing hormone after stimulation with gonadotropin-releasing factor. The response to the introduction of the releasing factor increases with puberty and from 2-3-fold becomes 6-10-fold.

Follicle-stimulating hormone in boys from younger to older school age increases from 3 - 4 to 11 - 13 mcU / ml, in girls over the same years - from 2 -8 to 3 - 25 mcU / ml. In response to the introduction of the releasing factor, hormone secretion approximately doubles, regardless of age.

Thyroid

The rudiment of the thyroid gland in the human embryo is clearly detected by the end of the 1st month of intrauterine development with a length of the embryo of only 3.5-4 mm. It is located at the bottom oral cavity and is a thickening of the ectodermal cells of the pharynx along the midline of the body. From this thickening, an outgrowth is directed into the underlying mesenchyme, forming an epithelial diverticulum. Lengthening, the diverticulum acquires a bilobed structure in the distal part. The stalk that connects the thyroid anlage to the tongue (thyroid-lingual duct) becomes thinner and gradually fragments, and its distal end differentiates into the pyramidal process of the thyroid gland. In addition, two lateral thyroid rudiments, which are formed from the caudal part of the embryonic pharynx, take part in the formation of the thyroid gland. The first follicles in the gland tissue appear on the 6-7th week of intrauterine development. Vacuoles appear in the cytoplasm of cells at this time. From the 9th - 11th week, droplets of colloid appear among the mass of follicle cells. From the 14th week, all follicles are filled with colloid. The thyroid gland acquires the ability to absorb iodine by the time a colloid appears in it. The histological structure of the embryonic thyroid gland after the formation of follicles is similar to that in adults. Thus, by the fourth month of intrauterine life, the thyroid gland becomes fully formed, structurally and functionally active. The regulation of fetal thyroid function is carried out primarily by the pituitary gland's own thyroid-stimulating hormone, since the mother's analogous hormone does not penetrate the placental barrier. The thyroid gland of a newborn has a mass of 1 to 5 g. Until about 6 months of age, the mass of the thyroid gland may decrease. Then begins a rapid increase in the mass of the gland up to 5-6 years of age. Then the growth rate slows down until the prepubertal period. At this time, the growth of the size and mass of the gland accelerates again. Here are the average indicators of the mass of the thyroid gland in children of different ages. With age, the size of nodules and the content of colloid increase in the gland, the cylindrical follicular epithelium disappears and flat appears, the number of follicles increases. The final histological structure of iron acquires only after 15 years.

Main thyroid hormones glands are thyroxine and triiodothyronine(T 4 and Tz). In addition, the thyroid gland is a source of another hormone - thyrocalcitonin, which is produced by C-cells of the thyroid gland. Being a polypeptide consisting of 32 amino acids, it is of great importance in the regulation of phosphorus-calcium metabolism, acting as an antagonist of parathyroid hormone in all reactions of the latter to an increase in blood calcium levels. Protects the body from excess calcium intake by reducing calcium reabsorption in the tubules of the kidney, calcium absorption from the intestine and increasing calcium fixation in bone tissue. The secretion of thyrocalcitonin is regulated both by the level of blood calcium and by changes in gastrin secretion when calcium-rich foods (cow's milk) are taken.

The function of the thyroid gland to produce calcitonin matures early, and there is a high level of calcitonin in the blood of the fetus. In the postnatal period, the concentration in the blood decreases and is 30 - 85 µg%. A significant part of triiodothyronine is not formed in thyroid gland, and on the periphery by monodiiodination of thyroxine. The main stimulator of the formation of Tz and Td is the regulating influence of the pituitary gland through a change in the level of thyroid-stimulating hormone. Regulation is carried out through feedback mechanisms: an increase in the level of circulating Tz in the blood inhibits the release of thyroid-stimulating hormone, a decrease in Tz has the opposite effect. The maximum levels of thyroxine, triiodothyronine and thyroid-stimulating hormone in the blood serum are determined in the first hours and days of life. This indicates a significant role of these hormones in the process of postnatal adaptation. Subsequently, there is a decrease in hormone levels.

thyroxine and triiodothyronine have a profound effect on children's body. Their action determines normal growth, normal maturation of the skeleton (bone age), normal differentiation of the brain and intellectual development, normal development of skin structures and its appendages, increased oxygen consumption by tissues, accelerated use of carbohydrates and amino acids in tissues. Thus, these hormones are universal stimulants of metabolism, growth and development. Insufficient and excessive production of thyroid hormones has a variety of and very significant violations vital activity. At the same time, insufficiency of thyroid function in the fetus may not significantly affect its development, since the placenta well passes maternal thyroid hormones (except for thyroid hormone). Similarly, the fetal thyroid gland can compensate for the insufficient production of thyroid hormones by the thyroid gland of a pregnant woman. After the birth of a child, thyroid insufficiency should be recognized as early as possible, since a delay in treatment can be extremely difficult for the development of the child.

Many tests have been developed to judge the functional state of the thyroid gland. They are used in clinical practice.

Indirect tests:

1. The study of bone age is carried out radiologically. It can detect a slowing down of the appearance of ossification points in thyroid insufficiency (hypofunction)

2. An increase in blood cholesterol also indicates a hypofunction of the thyroid gland.

3. Decreased basal metabolism with hypofunction, increased - with hyperfunction

4. Other signs of hypofunction: a) decrease in creatinuria and change in the ratio of creatine / creatinine in the urine; b) increase R-lipoproteins; c) decrease in level alkaline phosphatase, hypercarotenemia and insulin sensitivity, d) protracted physiological jaundice due to impaired glucuronidation of bilirubin.

Direct tests:

1. Direct radioimmunological study of the child's blood hormones (Tz, T 4 , TSH).

2. Determination of protein-bound iodine in serum. The content of protein-bound iodine (PBI), reflecting the concentration of the hormone on the way to the tissues, in the first week of postnatal life varies within 9-14 µg%. In the future, the level of SBI decreases to 4.5 - 8 µg%. Butanol-extracted iodine (BEI), which does not contain inorganic iodide, more accurately reflects the level of the hormone in the blood. BEI is usually less than SBI by 0.5 µg%.

3. Labeled triiodothyronine fixation test, which avoids irradiation of the body. Labeled triiodothyronine is added to the blood, which is fixed by plasma proteins - thyroid hormone transporters. With a sufficient amount of the hormone, fixation of triiodothyronine (labeled) does not occur.

With a lack of hormones, on the contrary, a large inclusion of triiodothyronine is observed.

There is a difference in the amount of fixation on proteins and cells. If there is a lot of hormone in the blood, then the introduced triiodothyronine is fixed by blood cells. If the hormone is low, then, on the contrary, it is fixed by plasma proteins, and not by blood cells.

There are also a number of clinical signs reflecting hypo- or hyperfunction of the thyroid gland. Thyroid dysfunction can manifest itself:

a) hormone deficiency - hypothyroidism. The child has general lethargy, lethargy, adynamia, loss of appetite, constipation. The skin is pale, dotted with dark spots. Tissue turgor is reduced, they are cold to the touch, thickened, edematous, the tongue is wide, thick. Delayed development of the skeleton - growth retardation, underdevelopment of the nasopharyngeal region (thickening of the base of the nose). Short neck, low forehead, thickened lips, coarse and sparse hair. Congenital hypothyroidism is manifested by a group of nonspecific signs. These include a large body weight at birth, a protracted nature of jaundice, an increase in the abdomen, a tendency to delay stool and late meconium discharge, a weakening or complete absence of a sucking reflex, and often difficult nasal breathing. In the following weeks, a lag in neurological development becomes noticeable, a long-term preservation of muscle hypertension, drowsiness, lethargy, a low timbre of voice when crying. For early detection of congenital hypothyroidism, a radioimmunological study of thyroid hormones in the blood of newborns is carried out. This form of hypothyroidism is characterized by a significant increase in the content of thyroid-stimulating hormone;

b) increased production - hyperthyroidism. The child is irritable, there are hyperkinesias, hyperhidrosis, increased tendon reflexes, emaciation, tremor, tachycardia, bulging eyes, goiter, Graefe's symptoms (delay in lowering the eyelids - lag upper eyelid when looking from top to bottom with exposure of the sclera), widening of the palpebral fissure, rarity of blinking (normally within 1 min 3 - 5 blinks), violation of convergence with averting the gaze when trying to fix on a nearby object (Mobius symptom);

c) normal hormone synthesis (euthyroidism). The disease is limited only by morphological changes in the gland during palpation, since the gland is accessible for palpation. A goiter is any enlargement of the thyroid gland. It occurs:

a) with compensatory hypertrophy of the gland in response to iodine deficiency due to hereditary mechanisms of biosynthesis disturbance or an increased need for thyroid hormone, for example, in children in puberty;

b) with hyperplasia, accompanied by its hyperfunction (Graves' disease);

c) with a secondary increase in inflammatory diseases or tumor lesions.

Goiter it is diffuse or nodular (the nature of the tumor), endemic and sporadically.

parathyroid gland

The parathyroid glands arise at the 5-6th week of intrauterine development from the endodermal epithelium of the III and IV gill pockets. The formed epithelial buds on 7th -8th week, they are laced from the site of their origin and join the posterior surface of the lateral lobes of the thyroid glands. The surrounding mesenchyme grows into them along with the capillaries. The connective tissue capsule of the gland is also formed from the mesenchyme. During the entire prenatal period, epithelial cells of only one type can be found in the gland tissue - the so-called chief cells. There is evidence of the functional activity of the parathyroid glands even in the prenatal period. It contributes to the preservation of calcium homeostasis relatively independent of fluctuations in the mineral balance of the mother's body. By the last weeks of the intrauterine period and in the first days of life, the activity of the parathyroid glands increases significantly. It is impossible to exclude the participation of the parathyroid hormone in the mechanisms of adaptation of the newborn, since homeostasis of the calcium level ensures the implementation of the effect of a number of tropic pituitary hormones on the tissue of the target glands and the effect of hormones, in particular the adrenal gland, on peripheral tissue cell receptors.

In the second half of life, a slight decrease in the size of the main cells is found. The first oxyphilic cells appear in the parathyroid glands after 6-7 years of age, their number increases. After 11 years, an increasing number of fat cells appear in the gland tissue. The mass of the parenchyma of the parathyroid glands in a newborn is on average 5 mg, by the age of 10 it reaches 40 mg, in an adult - 75-85 mg. These data refer to cases where there are 4 parathyroid glands and more. In general, the postnatal development of the parathyroid glands is regarded as a slowly progressive involution. The maximum functional activity of the parathyroid glands refers to the perinatal period and the first - second years of life of children. These are periods of maximum intensity of osteogenesis and intensity of phosphorus-calcium metabolism.

The parathyroid hormone, together with vitamin D, ensures the absorption of calcium in the intestine, the reabsorption of calcium in the tubules of the kidney, the leaching of calcium from the bones, and the activation of osteoclasts in bone tissue. Regardless of vitamin D, parathyroid hormone inhibits the reabsorption of phosphate by the tubules of the kidneys and promotes the excretion of phosphorus in the urine. According to its physiological mechanisms, parathyroid hormone is an antagonist of thyrocalcitonin of the thyroid gland. This antagonism ensures the friendly participation of both hormones in the regulation of calcium balance and bone tissue remodeling. Activation of the parathyroid glands occurs in response to a decrease in the level of ionized calcium in the blood. Emission increase parathyroid hormone in response to this stimulus, it contributes to the rapid mobilization of calcium from bone tissue and the inclusion of slower mechanisms - an increase in calcium reabsorption in the kidneys and an increase in calcium absorption from the intestines.

Parathyroid hormone affects on the balance of calcium and through a change in the metabolism of vitamin D contributes to the formation in the kidneys of the most active derivative of vitamin D - 1,25-dihydroxycholecalciferol. Calcium starvation or malabsorption of vitamin D underlying rickets in children is always accompanied by hyperplasia of the parathyroid glands and functional manifestations of hyperparathyroidism, however, all these changes are a manifestation of a normal regulatory response and cannot be considered diseases of the parathyroid glands. In diseases of the parathyroid glands, conditions may occur increased function- hyperparathyroidism or reduced function - hypoparathyroidism. Moderate pathological changes in the function of the glands are relatively difficult to differentiate from secondary, i.e., its regulatory changes. Methods for studying these functions are based on studying the reaction of the parathyroid glands in response to natural stimuli - changes in the level of calcium and phosphorus in the blood.

Methods for the study of parathyroid glands in the clinic can also be direct and indirect. The direct and most objective method is to study the level of parathyroid hormone in the blood. So, when using the radioimmunological method, the normal level of parathyroid hormone in the blood serum is 0.3 - 0.8 ng / ml. The second most accurate laboratory method is the study of the level of ionized calcium in the blood serum. Normally, it is 1.35 - 1.55 mmol / l, or 5.4 - 6.2 mg per 100 ml.

Significantly less accurate, but the most widely used laboratory method is the study of the level of total calcium and phosphorus in the blood serum, as well as their excretion in the urine. increased to 3.2 - 3.9 mmol / l. Hyperparathyroidism is accompanied by an increase in the level of calcium in the blood serum up to 3-4 mmol/l and a decrease in the content of phosphorus up to 0.8 mmol/l. Changes in the levels of calcium and phosphorus in the urine with changes in the level of parathyroid hormone are the opposite of their content in the blood. So, with hypoparathyroidism, the level of calcium in the urine can be normal or reduced, and the content of phosphorus always decreases. With hyperparathyroidism, the level of calcium in the urine increases significantly, and phosphorus is significantly reduced. Often, various functional tests are used to identify the altered function of the parathyroid glands: intravenous administration of calcium chloride, the appointment of agents such as complexones (ethylenediaminetetraacetic acid, etc.), parathyroid hormone or adrenal glucocorticoids. With all these tests, changes in the level of calcium in the blood are achieved and the reaction of the parathyroid glands to these changes is examined.

Clinical signs of changes in the activity of the parathyroid glands include symptoms of neuromuscular excitability, bones, teeth, skin and its appendages

Clinically, parathyroid insufficiency manifests itself depending on the timing of onset and severity in different ways. For a long time, symptoms from nails, hair, teeth (trophic disorders) persist. In congenital hypoparathyroidism, bone formation is significantly impaired (early onset of osteomalacia). Increased autonomic lability and excitability (pylorospasm, diarrhea, tachycardia). There are signs of increased neuromuscular excitability (positive symptoms of Khvostek, Trousseau, Erb). Some symptoms occur acute spasm. Seizures are always tonic, predominantly affecting the flexor muscles, and occur in response to sharp tactile irritation during swaddling, examination, etc. From the side of the upper limbs, the "obstetrician's hand" is characteristic, from the side lower extremities- pressing the legs, bringing them together and bending the feet. Laryngospasm usually occurs with convulsions, but may be without them, characterized by spasm of the glottis. More often occurs at night. There is noisy breathing with the participation of the chest, the child turns blue. Fright increases the manifestations of laryngospasm. Loss of consciousness may occur.

Hyperparathyroidism is accompanied by severe muscle weakness, constipation, bone pain Often there are bone fractures. X-ray in the bones are found areas of rarefaction in the form of cysts. At the same time, the formation of calcifications is possible in soft tissues.

In the adrenal glands, two layers, or substances, are distinguished: cortical and medulla, with the former accounting for approximately 2/3 of the total mass of the adrenal gland. Both layers are endocrine glands. Their functions are very diverse. In the adrenal cortex, corticosteroid hormones are formed, among which the most important are glucocorticoids (cortisol), mineralocorticoids (aldosterone) and androgens.

The adrenal glands are laid in humans on the 22-25th day of the embryonic period. The cortex develops from the mesothelium, the medulla develops from the ectoderm and somewhat later than the cortex.

The mass and size of the adrenal glands depend on age. In a two-month-old fetus, the mass of the adrenal glands is equal to the mass of the kidney; in a newborn, their value is 1/3 of the size of the kidney. After birth (in the 4th month), the mass of Chechnya is reduced by half; after the goal she begins to gradually increase again.

Histologically, there are 3 zones in the adrenal cortex: glomerular, fascicular and reticular. The synthesis of certain hormones is associated with these zones. It is believed that only the synthesis of aldosterone occurs in the glomerular zone, while glucocorticoids and androgens are synthesized in the bundle and reticular zone.

There are quite significant differences in the structure of the adrenal glands in children and adults. In this regard, it is proposed to distinguish a number of types in the differentiation of the adrenal glands.

1. Embryonic type. The adrenal gland is massive and consists entirely of cortical substance. The cortical zone is very wide, the fascicular zone is indistinct, and the medulla is not detected

2. Early childhood type. In the first year of life, the process of reverse development of cortical elements is observed. The cortical layer becomes narrow From the age of two months, the fascicular zone becomes more and more distinct; glomerular has the form of separate loops (from 4 - 7 months to 2 - 3 years of life).

3. Children's type (3 - 8 years). By 3-4 years, there is an increase in the layers of the adrenal gland and the development connective tissue in the capsule and bundle zone. The mass of the gland increases. The reticular zone is differentiated.

4. Teenage type (from 8 years old). There is an increased growth of the medulla. The glomerular zone is relatively wide, the differentiation of the cortex is slower.

5. Adult type. A fairly pronounced differentiation of individual zones is already noted.

Involution of the fetal cortex begins shortly after birth, resulting in the adrenal glands losing 50% of their original mass by the end of the 3rd week of life. By the age of 3-4, the fetal cortex completely disappears. It is believed that the fetal cortex produces mainly androgynous hormones, which gave the right to call it an accessory gonad.

The final formation of the cortical layer ends by 10-12 years. The functional activity of the adrenal cortex has quite large differences in children of different ages.

During childbirth, the newborn receives an excess of corticosgeroids from the mother. which leads to suppression of adrenocorticotropic activity of the pituitary gland. This is also associated with the rapid involution of the fetal zone. In the first days of life, the newborn excretes mainly metabolites of maternal hormones in the urine. By the 4th day, there is a significant decrease in both excretion and production of steroids. At this time, clinical signs of adrenal insufficiency may also occur. By the 10th day, the synthesis of hormones of the adrenal cortex is activated.

In children of early, preschool and primary school age, the daily excretion of 17-hydroxycorticosgeroids is significantly lower than in older schoolchildren and adults. Up to 7 years, there is a relative predominance of 17-deoxycorticosterone.

In the fractions of 17-hydroxycorhycosgeroids in urine, the excretion of tetrahydrocorgizol and tetrahydrocortisone predominates in children. The isolation of the second fraction is especially large at the age of 7-10 years.

Excretion of 17-ketosteroids also increases with age. At the age of 7-10 years, the excretion of dehydroepiandrosgerone increases, at 11-13 years of age - 11-deoxy-17-corticosteroids, androsterone and thiocholanolone. In boys, the excretion of the latter is higher than in girls. In puberty, the release of androsterone in boys doubles, in girls it does not change.

For diseases caused lack of hormones include acute and chronic adrenal insufficiency. Acute adrenal insufficiency is one of the relatively common causes of severe condition and even death in children with acute childhood infections. immediate cause The occurrence of acute adrenal insufficiency may be adrenal hemorrhage or depletion during severe acute illness and failure to activate with an increase in hormone demand. This condition is characterized by a drop in blood pressure, shortness of breath, thready pulse, often vomiting, sometimes multiple, liquid with a hum, a sharp decrease in all reflexes. Typical is a significant increase in the level of potassium in the blood (up to 25 - 45 mmol / l), as well as hyponatremia and hypochloremia.

Chronic adrenal insufficiency is manifested by physical and psychological asthenia, gastrointestinal disorders (nausea, vomiting, diarrhea, abdominal pain), anorexia. Frequent pigmentation of the skin - grayish, smoky or having various shades of dark amber or chestnut, then bronze and finally black. Pigmentation is especially pronounced on the face and neck. Weight loss is usually noted.

Hypoaldosteronism is manifested by high diuresis, often vomiting. In the blood, hyperkalemia is stated, manifested by cardiovascular insufficiency in the form of arrhythmia, heart block, and hyponatremia.

Diseases associated with excessive production of hormones of the adrenal cortex include Cushing's disease, hyperaldosteronism, adrenogenital syndrome, etc. Cushing's disease of adrenal origin is associated with hyperproduction of 11,17-hydroxycorticosteroids. However, there may be cases of increased production of aldosgerone, androgens and estrogens. The main symptoms are muscle atrophy and weakness due to increased breakdown of beta, negative nitrogen balance. There is a decrease in bone ossification, especially of the vertebrae.

Clinical Cushing's disease is manifested by obesity with a typical distribution of the subcutaneous fat layer. The face is round, red, there are hypertension, hypertrichosis, striae and impurity of the skin, growth retardation, premature hair growth, deposition of the subcutaneous fat layer in the region of the VII cervical vertebra.

Primary aldosgeronism. Kona is characterized by a number of symptoms associated primarily with the loss of potassium in the body and the effect of insufficient potassium on kidney function, skeletal muscle and cardiovascular system. Clinical symptoms are muscle weakness with normal development muscles, general weakness and fatigue. As with hypocalcemia, a positive symptom of Khvostek, Trousseau, and tetany attacks appear. There is polyuria and associated polydipsia, which is not relieved by the introduction of antidiuretic hormone. As a result, patients experience dry mouth. Arterial hypertension is noted.

At the core adrenogenital syndrome predominant production of androgens. Low levels of blood cortisol due to a deficiency of 21-hydroxylase in the adrenal glands cause increased production of ACTH, which stimulates the adrenal gland. 17-hydroxyprogesterop accumulates in the gland, which is excreted in the urine in excess amounts.

Clinically, girls have false hermaphroditism, and boys have false premature maturation.

A characteristic clinical symptom of congenital adrenal hypertrophy is the virilizing and anabolic action of androgens. It can manifest itself in the third month of the prenatal period, and in girls it is noticeable immediately after birth, and in boys after some time.

Girls signs of adrenogenital syndrome are the preservation of the urogenital sinus, an increase in the clitoris, which resembles male genital organs with hypospadias and bilateral cryptorchidism. The resemblance is enhanced by the wrinkled and pigmented labia, similar to the scrotum. This leads to misdiagnosis of the sex of female pseudohermaphroditism.

Boys there is no violation of embryonic sexual differentiation. The patient has faster growth, enlargement of the penis, early development of secondary sexual characteristics: a decrease in the timbre of the voice, the appearance of pubic hair (usually at the age of 3-7 years). This premature somatic development of the child is not true puberty, as the testicles remain small and immature, which is a differential sign. Cells and spermatogenesis are absent.

In patients of both sexes, there is an increase in growth, bone development is several years ahead of age. As a result of premature closure of the epiphyseal cartilages, the patient's growth stops before he reaches his usual average height (in adulthood, patients are undersized).

In girls, sexual development is impaired. They develop hirsugism, seborrhea, acne, low voice, mammary glands do not increase, menstruation is absent. Outwardly, they look like men.

In 1/3 of the patients, water-mineral metabolism disorders are added. Sometimes this violation in children is predominant in the clinical picture of the disease. In children, uncontrollable vomiting and diarrhea appear. Due to the abundant loss of water and salts, a clinical picture of toxic dyspepsia is created.

Pancreas

Cells possessing the properties of endocrine elements are found in the epithelium of the tubules of the developing pancreas already in a 6-week-old smbryo. At the age of 10-13 weeks. it is already possible to identify an islet containing A- and B-insulocytes in the form of a nodule growing from the wall of the excretory duct. At 13-15 weeks, the islet is laced from the wall of the duct. Subsequently, the histological differentiation of the islet structure proceeds, the content and mutual arrangement A- and B-insulocytes. Islets of a mature type, in which A- and B-cells, surrounding the sinusoidal capillaries, are evenly distributed throughout the islet, appear in the 7th month of intrauterine development. The largest relative mass of endocrine tissue in the composition of the pancreas is observed at the same time and amounts to 5.5 - 8% of the total mass of the organ. By the time of birth, the relative content of endocrine tissue decreases by almost half and by the first month it increases again to 6%. By the end of the first year, there is again a decrease to 2.5-3%, and the relative mass of endocrine tissue remains at this level throughout the entire period of childhood. The number of islets per 100 mm 2 of tissue in a newborn is 588, by 2 months it is 1332, then by 3-4 months it drops to 90-100 and remains at this level up to 50 years.

Already from the 8th week of the intrauterine period, glucagon is detected in wasp cells. By 12 weeks, insulin is determined in P-cells, and at almost the same time it begins to circulate in the blood. After differentiation of the islets, D-cells containing somatostatin are found in them. Thus, the morphological and functional maturation of the islet apparatus of the pancreas occurs very early and significantly ahead of the maturation of the exocrine part. At the same time, the regulation of insulin incretion in the prenatal period and in the early stages of life differs in certain features. In particular, glucose at this age is a weak stimulator of insulin release, and amino acids have the greatest stimulating effect - first leucine, in the late fetal period - arginine. The concentration of insulin in the blood plasma of the fetus does not differ from that in the blood of the mother and adults. Proinsulin is found in the tissue of the fetal gland in high concentration. However, in premature infants, plasma insulin concentrations are relatively low, ranging from 2 to 30 mcU/mL. In newborns, insulin release increases significantly during the first days of life and reaches 90-100 IU / ml, correlating relatively little with blood glucose levels. The excretion of insulin in the urine during the period from the 1st to the 5th day of life increases 6 times and is not associated with kidney function. Concentration glucagon in the blood of the fetus increases along with the timing of intrauterine development and after the 15th week it already differs little from its concentration in adults - 80-240 pg / ml. turn out to be very close. The main stimulator of glucagon release in the perinatal period is the amino acid alanine.

Somatostatin- the third of the main hormones of the pancreas. It accumulates in D-cells somewhat later than insulin and glucagon. While there is no convincing evidence of significant differences in the concentration of somatostatin in young children and adults, however, the reported data on the range of fluctuations are for newborns 70-190 pg / ml, infants - 55-186 pg / ml, and for adults - 20-150 pg /ml, i.e. the minimum levels definitely decrease with age.

In the clinic of childhood diseases, the endocrine function of the pancreas is studied mainly in connection with its effect on carbohydrate metabolism. Therefore, the main method of research is to determine the level of sugar in the blood and its changes over time under the influence of food loads of carbohydrates. Main clinical signs diabetes in children are increased appetite (polyphagia), weight loss, thirst (polydipsia), polyuria, dry skin, feeling weak. Often there is a kind of diabetic "blush" - pinking of the skin on the cheeks, chin and superciliary arches. Sometimes it is combined with itching of the skin. During the transition to a coma with increased thirst and polyuria, headache, nausea, vomiting, abdominal pain and then a consistent violation of the functions of the central nervous system, excitation, depression and loss of consciousness. A diabetic coma is characterized by a decrease in body temperature, pronounced muscle hypotension, softness of the eyeballs, Kussmaul type breathing, and the smell of acetone in the exhaled air.

Hyperinsulinism manifests itself periodically the occurrence of hypoglycemic conditions in a child of varying severity up to hypoglycemic coma. Moderate hypoglycemia is accompanied by an acute feeling of hunger, general weakness, headache, chilliness, cold sweat, hand tremor, drowsiness. With aggravation of hypoglycemia, the pupils dilate, vision is impaired, consciousness is lost, convulsions occur with a general increased muscle tone. The pulse is normal in frequency or slow, the body temperature is often normal, there is no smell of acetone. Laboratory determined severe hypoglycemia in the absence of sugar in the urine.

Sex glands, sex formation and maturation

The process of formation of the sexual phenotype in a child takes place during the entire period of development and maturation, however, two periods of life, and, moreover, rather short ones, turn out to be the most significant in terms of scrap. This is the period of sex formation in fetal development, which takes mainly about 4 months, and the period of puberty lasting 2-3 years for girls and 4-5 years for boys

Primary germ cells in the male and female embryo are histologically completely identical and have the ability to differentiate in two directions up to the 7th week of the prenatal period. At this stage, both internal genital ducts are also present - the primary kidney (Wolffian duct) and the paramesonephric (Mullerian duct). The primary tone consists of the medulla and cortex.

The basis of primary sex differentiation is the chromosome set of a fertilized egg. In the presence of a Y chromosome in this set, a histocompatibility cell surface antigen, called the H antigen, is formed. It is the formation of this antigen that induces the formation of a male gonad from an undifferentiated germ cell.

The presence of an active Y chromosome contributes to the differentiation of the medulla of the gonads in the male direction and the formation of the testis. The cortical layer will atrophy. This occurs between the 6th and 7th weeks of the intrauterine period. From the 8th week, interstitial testicular glandocytes (Leydig cells) are already determined in the testis. If the influence of the Y-chromosome did not manifest itself until the 6-7th week, then the primary gonad is transformed due to the cortical layer and turns into an ovary, and the medulla is reduced.

Thus, the formation of the male sex appears to be an active, controlled transformation, while the formation of the female sex is a natural, spontaneously ongoing process. In the subsequent stages of male differentiation, the hormones produced by the formed testicle become a direct regulatory factor. The testicle begins to produce two groups of hormones. The first group - testosterone and ditidrotestosterone, formed in testicular glandulocytes. The activation of these cells occurs due to the chorionic gonadotropin produced by the placenta and, possibly, the luteinizing hormone of the fetal pituitary gland. The effect of testosterone can be divided into general, requiring relatively low concentrations of tormon, and local, possible only with high levels hormone in the microregion of localization of the testicle itself. Consequence general action is the formation of the external genital organs, the transformation of the primary genital tubercle into the penis, the formation of the scrotum and urethra. The local effect leads to the formation of the vas deferens and seminal vesicles from the duct of the primary kidney.

The second group of hormones secreted by the fetal gesticles are hormones that lead to the initiation (inhibition) of the development of the paramesonephric duct. Inadequate production of these hormones can lead to the continuation of the development of this duct, sometimes unilaterally, where there is a defect in testicular function, and the formation of elements of the female genital internal organs here - the uterus and partly the vagina.

The failure of testosterone, in turn, can be the cause of non-realization and its general effect, i.e. the development of the external genitalia according to the female type.

With the female chromosome structure, the formation of the external and internal genital organs proceeds correctly, regardless of the function of the ovary. Therefore, even gross dysgenetic changes in the ovaries may not affect the formation of the genital organs.

The influence of male sex hormones produced by the testicles of the fetus affects not only the formation of male genital organs, but also the development of certain structures of the neuroendocrine system, and testosterone suppresses the formation of cyclic rearrangements of endocrine functions from the hypothalamus and pituitary gland.

Thus, in the natural differentiation of the organs of the male reproductive system, the timely and complete inclusion of the hormonal function of the testicles is of decisive importance.

Violations of the formation of the genital area can be associated with the following main causative factors

1) changes in the set and function of sex chromosomes, mainly leading to a decrease in the activity of the Y chromosome,

2) embryopagia, leading to testicular dysplasia and their low hormonal activity, despite an adequate set of XY chromosomes,

3) hereditary or arising in embryogenesis and fetogenesis changes in the sensitivity of the tissues of the embryo and fetus to the effects of testicular hormones,

4) insufficient stimulation of the endocrine function of the fetal testicles from the placenta, 5) with the female genotype (XX) - with the effects of exogenously administered male sex hormones, the presence of androgen-producing tumors in the mother, or an abnormally high synthesis of androgenic hormones by the adrenal glands of the fetus.

Signs of sexual dimorphism that occur during fetal development deepen very gradually in the process of postnatal growth. This also applies to slowly emerging differences in body type, often relatively well identified already in the period of first fullness, and in the significant originality of the psychology and range of interests of boys and girls, starting from the first games and drawings. Hormonal preparation for the period of puberty of children is also gradually carried out. So, already in the late fetal period, under the influence of androgens, sexual differentiation of the hypothalamus occurs. Here, of the two centers that regulate the release of releasing hormone for luteinizing hormone - tonic and cyclic, only the tonic activity remains active in boys. Obviously, such a preliminary preparation for puberty and a factor in further sweat specialization of the higher parts of the endocrine system are an increase in the level of gonadotrophic and sex hormones in children the first months of life and a significant "peak" in the production of adrenal androgens in children after the completion of the first traction. In general, the entire period of childhood to the onset of puberty is characterized by a very high sensitivity of hypogalamic centers to minimal levels of peripheral blood androgens. It is thanks to this sensitivity that the necessary restraining effect of the hypothalamus is formed on the production of gonadotrophic hormones and the beginning of the maturation of children.

Inhibition of the secretion of releasing hormone luteinizing hormone in the hypothalamus is provided by the active inhibitory effect of hypothetical "childhood support centers", excited in turn by low concentrations of blood sex steroids. In humans, “childhood maintenance centers” are probably located in the posterior hypothalamus and pineal gland. It is significant that this period occurs in all children on approximately the same dates in terms of bone age and relatively close indicators in terms of achieved body weight (separately for boys and girls). Therefore, it cannot be ruled out that the activation of the mechanisms of puberty is somehow connected with the general somatic maturity of the child.

The sequence of signs of puberty is more or less constant and has little to do with the specific date of its onset. For girls and boys, this sequence can be represented as follows.

For girls

9-10 years - growth of the pelvic bones, rounding of the buttocks, slight raised nipples of the mammary glands

10-11 years - dome-shaped raised mammary gland (stage "bud"), the appearance of hair on ..skirt.

11 - 12 years - enlargement of the external genitalia, changes in the epithelium of the vagina

12-13 years - development of glandular tissue of the mammary glands and areas adjacent to the areola, pigmentation of the nipples, the appearance of the first menstruation

13-14 years old - hair growth in the armpits, irregular menstruation.

14-15 years - change in the shape of the buttocks and gas

15-16 years - the appearance of acne, regular menstruation.

16-17 years old - skeletal growth arrest

For boys:

10-11 years - the beginning of the growth of the testicles and penis. 11 - 12 years - enlargement of the prostate, growth of the larynx.

12-13 years - significant growth of the testicles and penis. Growth of female pubic hair

13-14 years old - rapid growth of the testicles and penis, nodular induration of the peripapillary region, the beginning of voice changes.

14-15 years - growth of hair in the armpits, further change in voice, appearance of facial hair, pigmentation of the scrotum, first ejaculation

15-16 years - maturation of spermatozoa

16-17 years - male-type pubic hair growth, hair growth all over the body, the appearance of spermatozoa. 17 - 21 years old - skeletal growth arrest