Sex glands, their role in the process of growth, development of the body and puberty

The sex glands are glands of mixed secretion. External secretion is the secretion of germ cells (male sperm and female eggs), i.e. their release into the corresponding ducts.

Internal secretion is the release of sex hormones (male androgens and female estrogens) into the blood.

The effect that removal of the gonads has on the body has been known for a long time, since castration of livestock was used in ancient times to improve the working qualities of livestock and increase its weight. However, only in the middle of the 19th century it was precisely established that the influence of the gonads on hair, growth, physique and behavior depends on the entry into the blood of special substances produced by the testes of males and the ovaries of females.

These substances are the male hormone testosterone and its derivative androsterone and the female hormone estradiol.

Androgens determine the development of the reproductive apparatus and the growth of the genital organs, the development of sexual characteristics: voice timbre, structure of the larynx, skeleton, muscles, etc. Together with pituitary hormones, testosterone activates spermatogenesis. Hyperfunction of the testes at an early age leads to early puberty, rapid body growth and the development of secondary sexual characteristics. Damage to the testes or castration slows down or stops these processes.

Ovarian hyperfunction causes early puberty with pronounced secondary sexual characteristics and menstruation. Cases of early puberty have been described at 4-5 years of age!

The amount of sex hormones found in the blood is very low in the first days of life, and gradually increases, accelerating the pace of development, especially during the period of second childhood (8-12 years in boys and 8-11 in girls), adolescence (13-16 years boys, 12-15 years old girls) and youth (17-21 years old boys and 16-20 years old girls). In these age periods, the activity of the gonads is important for the rate of growth, morphogenesis and metabolic rate, that is, it can act as a leading factor in development. As the body ages, most often by the age of 70, there is a drop in gonadal incretion, which is important in the process of general “withering” of the body.

As research data show, the most significant changes in the body, and in particular its endocrine system, occur during puberty. During this period, a person reaches biological maturity. Under the influence of hormones from the endocrine glands, the final formation of the genital organs and glands occurs, and secondary sexual characteristics develop, which distinguishes one sex from the other.

Puberty begins earlier in girls than in boys. Starting from 7-8 years, fatty tissue is distributed according to the female type: fat is deposited in the mammary glands, on the hips, which is why the body shape is rounded first in the hips and torso, and then in the shoulder girdle and arms.

At the age of 13-15 years, rapid growth of the body in length is observed, hair appears on the pubis and in the armpits. Characteristic changes also occur in the genital organs: the uterus increases in size, follicles mature in the ovaries, and menstruation begins. For girls 19-20 years old, this is the time of the final formation of menstrual function and the onset of anatomical and physiological maturity of the whole organism.

In boys, puberty begins at 10-11 years old; at 12-13 years old, the shape of the larynx changes and the voice breaks; at 13-14 years old, the formation of a male-type skeleton begins. At 15-16 years old, hair grows rapidly under the arms and on the pubis, and also appears on the face. At 24-25 years of age, complete ossification of the skeleton ends.

The complex processes occurring in a child’s body during the transition period cannot, of course, be explained only by changes occurring in the sexual sphere. The whole body is being rebuilt. It develops quickly, internal organs work intensively, and the psyche changes.

The period of puberty is relatively long. In this case, the uneven development of various functional systems occurs, and the harmony in the activity of internal organs is disrupted. The heart grows faster than the blood vessels, resulting in an increase in blood pressure, which ultimately reduces the efficiency of the heart itself and often leads to dizziness. This is the cause of headaches, decreased performance, and periodic bouts of lethargy. Teenagers often experience fainting due to spasms of cerebral vessels. All these disorders, as a rule, disappear with the end of puberty.

In a teenager, the growth of the limbs outstrips the growth of the body, and as a result, movements become angular and poorly coordinated. At the same time, muscle strength increases, especially towards the end of the period. The growth of muscle mass in boys leads to the need to exercise it. Therefore, it is very important to wisely direct this energy to the right work.

Intensive growth, a sharp increase in the functions of the endocrine glands, structural and physiological changes in the body increase the excitability of the central nervous system. The emotions of adolescents are mobile, changeable, and contradictory. Increased sensitivity is often combined with callousness, shyness with swagger, excessive criticism (youthful maximalism) and intolerance towards parental care are manifested. During this period, neurotic reactions, irritability are sometimes observed, and in girls - tearfulness (during menstruation). New relationships between the sexes are emerging. Girls are becoming increasingly interested in their appearance. Boys try to show their strength to girls, and the first love “experiences” appear.

During this period, you should not draw the attention of adolescents to complex changes in their body and psyche, but it is necessary to explain the patterns and biological meaning of these changes. The art of the teacher and educator during this period is to find forms and methods of work that would switch the attention of children from sexual experiences to various types of activities.

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The functional state of a woman’s reproductive system is largely determined by the periods of life, among which it is customary to distinguish the following:

1) antenatal (intrauterine) period;

2) neonatal period (up to 10 days after birth);

3) childhood period (up to 8 years);

4) period of puberty, or puberty (from 8 to 16 years);

5) period of puberty, or reproductive (from 17 to 40 years);

6) premenopausal period (from 41 years to the onset of menopause);

7) postmenopausal period (from the moment of permanent cessation of menstruation).

Antenatal period

Ovaries. During embryonic development, the gonads are the first to develop (starting from 3-4 weeks of intrauterine life).

By 6-7 weeks of embryo development, the indifferent stage of gonad formation ends.

From 8-10 weeks - the formation of the female type of gonads begins.

At week 20, primordial follicles form in the fetal ovaries, which represent an oocyte surrounded by compacted epithelial cells.

At week 25, the tunica albuginea of ​​the ovary appears.

At 31-32 weeks, the granular cells of the inner lining of the follicle differentiate.

At 37-38 weeks, the number of cavity and ripening follicles increases.

By the time of birth, the ovaries are morphologically formed.

Internal genital organs. The fallopian tubes, the uterus and the upper third of the vagina originate from the paramesonephric ducts.

From 5-6 weeks of embryo development, the development of the fallopian tubes begins.

At 13-14 weeks, the uterus is formed by the fusion of the distal sections of the paramesonephric ducts: initially the uterus is bicornuate, but later acquires a saddle-shaped configuration, which is often preserved at the time of birth.

At 16-20 weeks, the cervix differentiates, its length by 40 weeks is 2/3 of the total length of the uterus.

At week 18, undifferentiated endometrium is revealed, tubular glands appear by the 24th week of antenatal development of the fetus.

The external genitalia from the 4th to the 7th week of the embryo’s life are of an indifferent nature and until the 16th week they practically do not change.

From the 17th week, the labia develop.

By 24-25 weeks, the hymen is clearly visible.

Hypothalamic-pituitary system. From 8-9 weeks of the antenatal period, the secretory activity of the adenohypophysis is activated: FSH and LH are determined in the pituitary gland, fetal blood and in small quantities in the amniotic fluid; during the same period, GTRF is identified.

At 10-13 weeks, neurotransmitters are detected.

From the 19th week, the secretion of prolactin by adenocytes begins.

Newborn period

The morphological features of the reproductive system observed within 10 days after birth are the basis for distinguishing the neonatal period.

Signs of estrogenic effects are found in the genitals and mammary glands of the newborn:

1) the epithelium of the vaginal mucosa consists of 30-40 layers and contains cells with a relatively high karyopyknotic index;

2) the cervical canal is filled with thick mucus;

3) proliferative and even secretory transformations are determined in the endometrium;

4) in 3% of newborn girls, desquamation of the endometrium occurs, in 25%, unchanged red blood cells are detected in vaginal smears;

5) often there is an enlargement of the mammary glands.

According to modern ideas the origin of estrogenic influence during this period is explained from the following positions: at the end of intrauterine development of the fetus, a high level of maternal estrogens inhibits the secretion of gonadotropins from the fetal pituitary gland; a sharp decrease in the mother’s estrogen content in the newborn’s body stimulates the release of FSH and LH by the girl’s adenohypophysis, which provides a short-term increase in the function of her ovaries.

By the 10th day of a newborn’s life manifestations of estrogenic effects are eliminated. The period of childhood is characterized by low functional activity of the reproductive system: the secretion of estradiol is insignificant, the maturation of follicles to the antral occurs rarely and unsystematically, the release of GTRF is inconsistent; receptor connections between subsystems are not developed, the secretion of neurotransmitters is scanty.

Puberty

During this period (from 8 to 16 years), not only the maturation of the reproductive system occurs, but also the physical development of the female body is completed: body growth in length, ossification of the growth zones of tubular bones, the physique and distribution of fat and muscle tissue according to the female type are formed.

Currently, in accordance with the degree of maturity of the hypothalamic structures, three periods of maturation of the hypothalamic-pituitary-ovarian system are distinguished.

The first period - prepubertal (8-9 years) - is characterized by increased secretion of gonadotropins in the form of individual acyclic emissions, estrogen synthesis is low; a “jump” in body growth in length is noted, the first signs of feminization of the physique appear: the hips are rounded due to an increase in the amount and redistribution of adipose tissue, the formation of the female pelvis begins, the number of epithelial layers in the vagina increases with the appearance of intermediate type cells.

The second period - the first phase of puberty (10-13 years) - is characterized by the formation of daily cyclicity and an increase in the secretion of GTRF, FSH and LH, under the influence of which the synthesis of ovarian hormones increases. The sensitivity of the receptor apparatus of all parts of the reproductive system increases. Upon reaching a certain high level estrogen provides a powerful release of gonadotropins, which, in turn, completes the process of follicle maturation and stimulates ovulation. The mammary glands begin to enlarge, pubic hair begins to grow, the vaginal flora changes - lactobacilli appear. This period ends with the appearance of the first menstruation - menarche, which coincides in time with the end of the rapid growth of the body in length.

The third period - the second phase of the pubertal period (14-16 years) - is characterized by the establishment of a stable rhythm of GTRF release, a high (ovulatory) release of FSH and LH against the background of their basal monotonic secretion (along with the existing negative feedback mechanism, positive feedback is formed). The development of the mammary glands and sexual hair is completed, the body grows in length, and the female pelvis is finally formed; The menstrual cycle becomes ovulatory.

The first ovulation represents the culmination of puberty, but does not mean puberty, which occurs by 16-17 years. Puberty is understood as the completion of the formation of not only the reproductive system, but also the entire woman’s body, prepared for conception, pregnancy, childbirth and feeding a newborn.

Puberty period (from 17 to 40 years)

The features of this period are manifested in specific morphofunctional transformations of the reproductive system.

Premenopausal (menopausal) period and postmenopause

The premenopausal period lasts from 41 years to the onset of menopause - the last menstruation in a woman's life, which occurs on average at the age of 50.8 years. During this period, the activity of the gonads fades, the basis of which is a violation of receptor connections in the hypothalamus-pituitary-ovarian system. A distinctive sign of the onset of the premenopausal period is a change in the rhythm and duration of menstruation, as well as the volume of menstrual blood loss: menstruation becomes less abundant (hypomenorrhea), their duration is shortened (oligomenorrhea), and the intervals between them increase (opsomenorrhea).

The following phases of the premenopausal period are conventionally distinguished:

1) hypoluteal - there are no clinical symptoms, there is a slight decrease in lutropin in the adenohypophysis and progesterone in the ovaries;

2) hyperestrogenic - characterized by the absence of ovulation (anovulatory menstrual cycle), cyclical secretion of FSH and LH, an increase in estrogen content, the consequence of these processes is a delay in menstruation for 2-3 months, often followed by bleeding; since luteinization of the cells of the granular layer of the inner shell of the follicle does not occur, the concentration of gestagens is minimal;

3) hypoestrogenic - amenorrhea is observed (absence of menstruation for 6 months or more), a significant decrease in estrogen levels - the follicle does not mature and atrophies early, the secretion of gonadotropins increases;

4) ahormonal - the functional activity of the ovaries stops, estrogens are synthesized in small quantities only by the adrenal cortex (compensatory hypertrophy of the cortex), the production of gonadotropins increases; clinically characterized by persistent amenorrhea.

It should be noted that the phases of the physiology of the menopausal period are distinguished rather arbitrarily, since normally there is no clear distinction between them.

The ahormonal phase coincides with the beginning of the postmenopausal period. Postmenopause is characterized by atrophy of the internal genital organs (the mass of the uterus decreases, its muscular elements are replaced by connective tissue, the vaginal epithelium becomes thinner due to a decrease in its layering), urethra, Bladder, pelvic floor muscles. In postmenopause, metabolism is disrupted, and pathological conditions cardiovascular, skeletal and other systems.

Selected lectures on obstetrics and gynecology

Ed. A.N. Strizhakova, A.I. Davydova, L.D. Belotserkovtseva

The human body is a complex of physiological systems (nervous, cardiovascular, respiratory, digestive, excretory, etc.). Normal operation These systems ensure the existence of man as an individual. If any of them is violated, disorders occur that are often incompatible with life. But there is a system that does not participate in life support processes, but its significance is extremely great - it ensures the continuation of the human race. This is the reproductive system. If all other vital systems function from the moment of birth to death, then the reproductive system “works” only when a woman’s body can bear, give birth and feed a child, i.e. in a certain age period, in the flourishing phase of all vital forces. This is the highest biological expediency. Genetically, this period is programmed for the age of 18-45 years. Reproductive system a woman has a complex structure due to the complexity of its function.

It includes higher regulatory mechanisms located at the base of the brain, closely connected by neural and vascular pathways with the brain appendage - the pituitary gland. In it, under the influence of impulses emanating from the brain, specific substances are formed - pituitary hormones. Through the bloodstream, these hormones reach the female reproductive gland - the ovary, in which female sex hormones - estrogens and progesterone are formed. Pituitary hormones play a decisive role in the development and formation of not only the genital organs, but also the entire female body. The genital organs include both external and internal genitalia (vagina, cervix, tubes and ovaries).

Female genital organs:
1 - vaginal mucosa; 2 - cervix; 3 - fallopian tube; 4 - fundus of the uterus; 5 - body of the uterus; 6 - corpus luteum; 7 - funnel of the oviduct; 8 - fimbria of the oviduct: 9 - ovary; 10 - uterine cavity

The ovary is a unique endocrine gland. In addition to the fact that it functions like any endocrine gland, secreting hormones, female reproductive cells - eggs - mature in it.

At the time of birth, the ovary contains about 7,000 eggs. Theoretically, each of them, after fertilization, can give rise to a new life. However, with age, their number progressively decreases: by the age of 20 it is 600,000, by the age of 40 - about 40,000, at the age of 50 there are only a few thousand, and after 60 years they cannot be detected. This excess supply of eggs preserves the possibility of childbearing even after the removal of one and a significant part of the other ovary.

Each egg is contained in a sac called a follicle. Its walls consist of cells that produce sex hormones. As the egg matures, the follicle grows and the production of estrogen increases. A mature egg is released from the ovary, and in place of the follicle a so-called corpus luteum is formed, which also secretes the hormonal substance progesterone. This hormone has multifaceted biological effects.

The uterus is a hollow muscular organ. The muscles of the uterus, which have a special structure, tend to increase in size and weight. Thus, the uterus of an adult non-pregnant woman weighs about 50 g. By the end of pregnancy, its weight increases to 1200 g and a fetus weighing more than 3 kg is inserted. The inner surface of the uterus is covered with a monthly lining that falls off and grows back. From the upper part of the uterus, its bottom, fallopian tubes (oviducts), consisting of a thin layer of muscles, lined inside with a mucous membrane covered with cilia. Wave-like movements of the tubes and vibrations of the cilia push the fertilized egg into the uterine cavity.

So, the female reproductive system consists of higher regulatory brain centers, endocrine glands (pituitary gland and ovaries), internal and external genital organs. Like all body systems, the reproductive system is established and begins to develop during fetal development. After birth, it functions differently depending on the woman's age. The following periods of functioning of the reproductive system are distinguished: childhood, puberty, reproductive (childbearing) period, menopause and postmenopause.

The period of childhood (from birth to 10 years) is also called the period of sexual rest, since the system practically does not function at this time. However, as studies have shown, even then negligible amounts of sex hormones are formed in the ovary, which play a certain role in the overall metabolism of the body. At this age, there is a gradual slight increase in the size of the internal and external genital organs in accordance with the overall growth of the body.

Puberty is characterized by significant changes in the girl’s entire body, which are a consequence of the action of female sex hormones. From the age of 10, the secretion of sex hormones in the ovary begins to increase. Signals for their formation and release come from certain structures of the brain, which by this age reach a certain degree of maturity. The first sign of the action of sex hormones is a growth spurt. Every mother knows that after a period of gradual growth at the age of 10-12 years, a girl immediately gains 8-10 cm, her body weight increases, and the formation of a female body type begins: the distribution of adipose tissue with predominant deposition on the hips, buttocks, and abdomen. The development of secondary sexual characteristics is noted: the mammary glands enlarge, their growth begins with darkening and enlargement of the nipples. At the age of 11, hair appears on the external genitalia, and at the age of 13, axillary hair appears. At about 13 years of age (with variations of a few months), menstruation begins, the first menstruation is called menarche. During this time, the internal and external genitalia increase in size. The appearance of menstruation does not mean the end of the period of sexual development - its first stage is over. The second stage lasts up to 16 (18) years and ends with the cessation of growth in length, i.e., with the formation of the skeleton. The pelvic bones are the last to stop growing, since bony pelvis is the basis of the so-called birth canal, through which the child is born. Body growth in length ends 2-2.5 years after the first menstruation, and growth of the pelvic bones by 18 years. In the second stage of puberty, the development of the mammary glands, genital and axillary hair is completed, and the internal genital organs reach their final size.

These changes occur under the influence of sex hormones. Many tissues of the body are the target of the action of sex hormones; they are called target tissues of sex hormones. These primarily include the genitals, mammary glands, as well as fatty, muscle, bones, hair follicles, sebaceous glands, leather. Even the blood is affected by ovarian hormones, changing its clotting ability. Hormones influence the central nervous system (processes of excitation and inhibition in the cerebral cortex), the behavior and mental activity of a woman, distinguishing her from a man, largely depend on them. During the second stage of puberty, the cyclic function of the entire reproductive system is formed: the periodicity of nerve signals and the release of pituitary hormones, as well as the cyclic function of the ovaries. Over a certain period of time, the egg matures and is released, and sex hormones are produced and released into the blood.

It is known that human body obeys certain biological rhythms - hourly, daily, seasonal. The ovaries also have a certain rhythm of work: within 2 weeks, an egg matures in the follicle and is released from the ovaries; over the next 2 weeks, a corpus luteum forms in its place. It reaches its peak and undergoes a reverse development. During the same time, the uterine cycle occurs in the uterus: under the influence of estrogen, the mucous membrane grows within 2 weeks, then, under the influence of progesterone, changes occur in it, preparing it for the reception of the egg in the event of its fertilization. Glands filled with mucus form in it, and it loosens. If pregnancy does not occur, the uterine mucosa is shed, the underlying vessels are exposed, and so-called menstrual bleeding occurs within 3-5 days. This ovarian and uterine cycle lasts 28 days in 75% of women: 15% - 21 days, 10% - 32 days and is stable. It does not change throughout the entire period of functioning of the reproductive system, stopping only during pregnancy. It can only be broken serious illnesses, stress, sudden changes in living conditions.

The reproductive (childbearing) period lasts from 18 to 45 years. This is the period of flowering of the whole organism, the time of its greatest physical and intellectual activity, when the body of a healthy woman can easily cope with the load (pregnancy and childbirth).

The climacteric period occurs at the age of 45-55 years. Klimax means “ladder” in Greek. At this age, the function of the reproductive system gradually declines: menstruation becomes scarcer, the interval between them lengthens. the process of follicle growth and egg maturation is disrupted, ovulation does not occur, and the corpus luteum does not form. Pregnancy is impossible. After the cessation of childbearing, the hormonal function of the ovaries also fades, and the formation and release of the hormone progesterone (hormone of the corpus luteum) is the first to be disrupted, while the formation and release of estrogens is still sufficient. Then the formation of estrogen decreases.

Speaking about the period of puberty, we noted that the signal for the beginning of the secretion of ovarian hormones comes from certain structures of the brain. In these same structures, aging processes begin, leading to disruption of cyclicity and a decrease in the hormone-forming function of the ovaries. However, during the menopause, sex hormones are formed in the ovaries, albeit in ever-decreasing quantities, but sufficient for the normal functioning of the whole organism. The culmination of the menopause is the last menstruation, which is called menopause. It occurs on average at the age of 50 years. Sometimes menstruation continues until age 55 (late menopause).

The postmenopausal period is divided into early postmenopause (the first 6 years after menopause) and late postmenopause (the terms are defined differently). At this age, the hormonal function of the ovaries ceases, and the ovary practically does not secrete sex hormones. Many manifestations of the aging process in the body are caused precisely by a deficiency of sex hormones. First of all, these are atrophic (reduction in size) changes in the genital organs - both external and internal. Atrophic changes also occur in the mammary glands, the glandular tissue of which is replaced by adipose tissue. The skin loses elasticity, becomes wrinkled, and becomes thinner. Changes occur in bone tissue - bones become more fragile, fractures occur much more often than in youth and heal more slowly. Perhaps there is no such process of a woman’s aging in which a deficiency of sex hormones would not be involved, if not directly, then indirectly, through metabolism. However, it would be incorrect to assume that aging is associated only with a decrease in the level of sex hormones in the body. Aging is an inevitable process, genetically programmed. starting in the brain, in the centers that regulate the function of all organs and systems of the body.

Each age period in a woman’s life is characterized by specific disorders and diseases of the reproductive system. Thus, gynecological diseases are rare in childhood. Almost the only disease in girls under 8-10 years of age is inflammation of the vagina and external genitalia. The cause of inflammation is banal microorganisms (streptococci and staphylococci), always present on the mucous membranes, including the vagina. But in weakened children, after infectious diseases (measles, scarlet fever, tonsillitis, influenza, pneumonia), especially if hygiene rules are not observed (daily washing), these microorganisms multiply and acquire aggressive properties, causing inflammatory changes. Pus-like discharge appears. redness, sometimes itching. These diseases do not require special treatment measures. It is recommended to carefully maintain cleanliness of the body, washing with light disinfectant solutions (a slightly pink solution of potassium permanganate or a solution of calendula tincture diluted in boiled water 1:100) and general measures. aimed at quickly restoring health after illness (good nutrition, physical education, hardening).

During puberty, menstrual irregularities are often observed. We must remember that after the first menstruation, approximately 10-15% of girls have regular menstruation within 1-1.5 years. If during this period your periods come irregularly at intervals of up to 40-60 days, then you should not worry. If after this period the cycle is not established, we can talk about a deviation from the norm and look for its cause. Sometimes this is due to intense exercise and irregular nutrition. Many girls during puberty follow a “cosmetic diet”. Afraid of gaining weight, they deliberately limit themselves in the proteins, fats and carbohydrates necessary for a growing body (for example, they do not eat bread, butter, meat). Weight loss at this age usually leads to disruption of the menstrual cycle, even to the point of cessation of menstruation if it occurs over a short period of time. It will be possible to restore the menstrual cycle with the help of a balanced diet and normalization of body weight. Medications, stimulating ovarian function, are used only for long-term (more than a year) delays in menstruation. A serious complication of puberty is the so-called juvenile uterine bleeding. They require hospital treatment, and after discharge, long-term medical observation and treatment to normalize ovarian function. At the same time, uterine bleeding at this age can be a symptom of non-gynecological diseases (for example, a disorder of the blood coagulation system). Bleeding during puberty requires careful examination to determine its true cause.

Pathology that requires examination is the late (after 16 years) onset of menstruation, the appearance of excess hair unusual for the female type, the absence of menstruation, especially against the background of pronounced underdevelopment of secondary sexual characteristics (for example, mammary glands). Delayed puberty, as a rule, is a sign of endocrine diseases, and sometimes congenital, genetically determined malformations of the reproductive system. The examination of such girls should not be postponed until after the age of 16. Timely identification of the causes of developmental disorders will allow them to be corrected in a timely manner. This is important not only for normalizing the functions of the reproductive system, but also relieves the girl from the consciousness of her inferiority, to which adolescents are especially sensitive at this age. Normal puberty is the key to the further function of the reproductive system. It is at this age that ovarian disorders develop, which subsequently lead to infertility, as well as miscarriage, disorders during pregnancy and childbirth.

The formation of the reproductive system begins in the antenatal period. The next stages of its development are the periods of childhood and adolescence. They are the determining factors in the formation of reproductive health. Knowledge of the characteristics of sexual development at these stages is necessary for proper prevention of reproductive disorders in women.

Development of the reproductive system in the antenatal period

The formation of the female reproductive system begins in the early antenatal period and ends in the period of biological maturity (the body's ability to reproduce).

Genetic sexual determination is realized from the moment
connections of female and male reproductive cells - gametes, i.e. from the period of conception.

According to genetic determination, primary germ cells that arise in the first 4-5 weeks differentiate into oogonia or spermatogonia, which in turn induce the formation of male or disturbances in the development of the adrenal glands from the surrounding somatic cells, more often to hyperplasia of their cortex and increased production of androgens, which is manifested by adrenogenital syndrome and other diseases.

In development ovaries The following stages are distinguished: 5-7 weeks - the period of indifferent gonads, 7-8 weeks - the beginning of sexual differentiation, 8-10 weeks - the period of oogonia reproduction, 10-20 weeks - the period of unseparated oocytes, 20-38 weeks - the period of primary follicles. Hormonal activity of the ovaries up to 28 weeks is accompanied by the death of the germinal elements of the gonads (oogonium, primordial follicles, etc.). Then the maturation of the follicles begins, and at 32-34 weeks the greatest hormonal activity takes place, which persists until the end of pregnancy. The structural development and hormonal activity of the ovaries are disrupted and delayed during the pathological course of pregnancy, which is manifested by ovarian disorders in the puberty period (disorders of sexual development, uterine bleeding, amenorrhea, etc.).

Laying of the external buttock organs occurs equally in embryos, regardless of gender, in the area of ​​the cloacal membrane at 5-7 weeks. Then a urorectal fold is formed, which divides the cloaca and its membrane into the anal and genitourinary parts, after which the isolated formation of the intestine and genitourinary system occurs. The development of the external genital organs, differentiated according to gender, occurs from the 3rd month of the intrauterine period (male at 9-10 weeks, female at 17-18 weeks).

Specific feminine traits genitals are acquired as early as 17-19 weeks of pregnancy. Further development and feminization of the genital organs occurs in parallel with the endocrine activity of the endocrine glands. Adverse effects during the pathological course of pregnancy can lead to a slowdown, less often to acceleration, or to other disturbances in the development of the external genitalia.

Vagina is formed from the 8th week, and its accelerated growth occurs after the 19th week of intrauterine life. In parallel with this, starting from the 8-10th week, differentiation of the vaginal mucosa occurs, desquamation of the epithelium of which occurs from the 30th week of pregnancy, and the processes of proliferation of the mucosa are especially pronounced in the last weeks of pregnancy.

The cytological picture of a vaginal smear in the antenatal period is characterized by wave-like changes depending on the predominant influence of estrogens (20-28 weeks, 37-40 weeks) or progesterone (29-36 weeks). The level of sex chromatin depends on the degree of saturation of the fetus with estrogen. Its highest level (41.5 ± 2%) in the vaginal epithelium is observed at 20-22 weeks of pregnancy, followed by a decrease (up to 11%) until the 29th week, a repeated increase (up to 21%) at the 34th week and a decrease ( up to 6%) by the end of pregnancy. These changes are due to the influence of estrogens on the state of the X chromosome in somatic cells, i.e. as this influence increases, the amount of sex chromatin decreases.
Development.tgtk;m also begins in early dates, first the cervix appears, then the body of the uterus, which are differentiated at the 4-5th month.

Their especially intensive growth is observed in the 6th month and at the end of the intrauterine period. By the 27-28th week of pregnancy, myometrial histogenesis is completed. The histogenesis of the endometrium ends by the 24th week, proliferative changes by the 32nd week, and secretory changes by the 33-34th week of the intrauterine period. Morphological and functional changes up to 32 weeks correspond to the stage of proliferation, and from the 33rd week of the intrauterine period - to the stage of secretory changes.

The movement of the boundaries of the endocervix epithelium near the vaginal epithelium deserves special attention. Thus, from the 33rd week, the prismatic epithelium of the endocervix covers the vaginal part of the cervix, and the persistence of this phenomenon in later stages of pregnancy and after birth can cause “congenital erosion” of the cervix, which should probably be considered a physiological phenomenon caused by hormonal influences.

The fallopian tubes are laid in 8-10 weeks of pregnancy, and by the 1st 6th week they are anatomically formed. Then, gradually until the end of pregnancy, their structural and functional differentiation occurs. Damaging factors during the pathological course of pregnancy disrupt the development of the uterus and tubes, both anatomically and functionally, or cause various malformations of the uterus.

Occurred in the antenatal period genital disorders may also affect the postnatal period (malformations of the uterus, tortuosity or obstruction of the fallopian tubes, infantilism, uterine hypoplasia, etc.).

Thus, the formation of the reproductive system begins in the early antenatal period in parallel with the formation of the endocrine system, i.e. with the development of the hypothalamus and pituitary gland, as well as peripheral endocrine glands - ovaries, adrenal glands and thyroid gland.

Antenatal period of puberty characterized by the wave-like processes of both the development of individual endocrine structures and the formation of correlative relationships between them. In this case, an increase in the activity of one of the peripheral endocrine glands is accompanied by a change in the activity of other glands and usually a decrease in it in the adenohypophysis.

Typically, endocrine activity of the adrenal glands and ovaries is preceded by its increase in the pituitary gland and thyroid gland.

First, functional activity pituitary gland, adrenal glands, thyroid gland and ovaries is under the controlling influence of the placenta, and in particular chorionic gonadotropin, the peaks of which are associated with the activation of endocrine organs in 9-10 and 32-34 weeks of pregnancy. This pattern determines the unity of the fetoplacental system. Correlative relationships in the pituitary gland - thyroid gland - adrenal glands - ovaries system are clearly defined already after 27-28 weeks of pregnancy.

Processes puberty and correlative relationships in the endocrine system in the antenatal period of ontogenesis are disrupted when exposed to harmful factors, which can also manifest themselves in the postnatal period. These disorders are characterized by activation, inhibition or other abnormal changes in puberty that occur after damage to even one of the endocrine organs. Typically, the thyroid gland and adrenal glands are more sensitive to harmful factors, developmental disorders of which lead to pathology of the maturation of the central nervous system and a decrease in adaptive mechanisms, especially during the neonatal period. Further, puberty is disrupted in the antenatal and postnatal periods. This manifests itself in the prepubertal and pubertal periods.

Development of the reproductive system in childhood and adolescence

The following periods of a girl’s sexual development are distinguished: newborn, “neutral” childhood (up to 7 years), prepubertal (from 8 years to the year of menarche), puberty (from the year of menarche to 16 years) and adolescence (16-18 years).

A newborn girl has differentiated female phenotype on the external genitalia: their skin is pigmented, the labia are swollen and hyperemic, the labia majora partially cover the labia minora, the clitoris is relatively large, the hymen is located deep in the genital cleft. The vagina with folded edematous mucosa has a length of 25-35 mm. The reaction of the vaginal contents is acidic, Dederlein's rods are found in it.

Vaginal smears show a high eosinophilic and karyopyknotic index. This picture is due to the estrogenic effect of the mother on the girl’s genitals. Already a week after birth, parabasal and basal cells predominate in smears, and coccal flora is noted. The uterus, 30 mm long, is located high in the abdominal cavity, in an anterior position, with a predominance of the size of the cervix over the body (3:1). The myometrium is well defined; erosion is often detected on the cervix due to movement of the boundaries of the prismatic epithelium of the endocervix. The endometrium is in the stage of secretory changes, often with menstrual-like discharge.

The fallopian tubes are relatively long (up to 35 mm), tortuous, with a pronounced muscular layer, and are well passable. The ovaries, measuring 15x2 5 mm with maturing follicles, are located in the abdominal cavity. They contain an abundance of primordial follicles (500,000-700,000 each) with a pronounced atresia process at various stages of development without ovulatory changes. Well-defined interstitial cells (theca cells) with high endocrine activity. There is a thin tunica albuginea, absence of the zona pellucida, moderate luteinization of theca cells, granulosa anisocytosis and an abundance of degenerated oocytes. The right ovary and tube are larger in size than the left ones.

IN "neutral" period There is a slow development of the genital organs with a number of features. The labia majora cover the labia minora only towards the end of the period; at 3-4 years, small vestibular glands appear, which mature at 6-7 years, and the large ones become poorly differentiated. There is a gradual descent of the uterus and ovaries into the small pelvis, a slow increase in the length of the vagina (up to 40 mm), a change in the ratio of the body to the cervix (from 3:1 to 1:1.5). Vaginal contents have an alkaline or neutral reaction with various coccal and rod flora. There are ripening, mature and atretic follicles without cyclic changes, their number is halved compared to the neonatal period.

Genitals girls in the prepubertal period continue to develop with their own characteristics. The genital organs become enlarged due to adipose tissue. By the end of this period, the vagina lengthens to 60-65 mm, the fornix is ​​formed, especially the posterior one with pronounced folding of the walls and thickened epithelium (CPI - up to 30%, EI - up to 20%). The reaction of vaginal contents is acidic, with Dederlein's rods.

The uterus increases to the size as at birth or more (weight 5-7 g), its body makes up 2/3, and the cervix 1/3. The endometrial glands hypertrophy and branch, and the functional and basal layers are clearly distinguished. The weight of the ovaries increases to 4-5 g, follicles intensively ripen in them, ovulation is possible, the number of follicles decreases to 100,000-300,000. Thus, all parts of the reproductive system intensively ripen and are ready for full functioning.

IN puberty the genital organs become similar to the organs of an adult woman: the vagina lengthens to 8-10 cm with folded mucosa, colpocytology characterizes cyclic changes, the weight of the uterus increases to 2-5 g, tubal peristalsis appears, and the integrating system for regulating reproductive function improves.

Puberty and puberty

Puberty is a transitional age between childhood and adulthood, during which not only the development of the genital organs occurs, but also general somatic development. Along with physical development, during this period the so-called secondary sexual characteristics begin to emerge more and more clearly, i.e. all those features that distinguish the female body from the male one.

In the process of normal physical development in childhood, body mass and length are important to characterize sexual characteristics. Body weight is more variable, as it depends to a greater extent on external conditions and nutrition. In healthy children, changes in body weight and length occur naturally. Girls reach their final height at puberty, when ossification of the epiphyseal cartilages is completed.

Because during puberty Growth is regulated not only by the brain, as in childhood, but also by the ovaries (“steroid growth”), then with the earlier onset of puberty, growth stops. Taking into account this relationship, two periods of increased growth are distinguished: the first at 4-7 years with a slowdown in body weight gain and at 14-15 years, when weight also increases. The development of children and adolescents can be divided into three stages. The first stage is characterized by increased growth without gender differences and continues until 6-7 years of age.

At the second stage (from 7 years to the onset of menarche), along with growth, the function of the gonads is already activated, especially pronounced after 10 years of age. If at the first stage girls and boys differ little in their physical development, then at the second these differences are clearly expressed. During this so-called prepubertal period, traits of one’s own gender appear: facial expression, body shape, and propensity for activities change, the development of secondary sexual characteristics begins, and menstruation appears.

At the third stage secondary sexual characteristics develop progressively: a mature mammary gland is formed, hair growth in the pubic and axillary areas is noted, and the secretion of the sebaceous glands of the face increases, often with the formation of acne. Differences in somatic characteristics also appear more clearly during this period. A typical female pelvis is formed: it becomes wider, the angle of inclination increases, the promantorium (promontory) protrudes into the entrance of the pelvis. The girl's body becomes round with the deposition of fatty tissue on the pubis, shoulders and sacro-gluteal region.

The process of puberty is regulated sex hormones which are produced by the gonads. Even before the appearance of the first menstruation, there is an increase in the function of the pituitary gland and ovaries. It is believed that the function of these glands already during this period occurs cyclically, although ovulation does not occur even in the first time after menarche. The beginning of the functioning of the ovaries is associated with the hypothalamus, where the so-called reproductive center is located. The release of follicular and gonadotropic hormones gradually increases, which leads to qualitative changes, the initial manifestation of which is menarche. Some time (from several months to 2-3 years) after the first menstruation, the follicles reach full maturity, which is accompanied by the release of an egg, which means the menstrual cycle becomes two-phase.

During puberty The release of hormones also increases. Steroid sex hormones stimulate the function of other endocrine glands, especially the adrenal glands. In the adrenal cortex, the production of mineral o- and glucocorticoids progresses, but the amount of androgens especially increases. It is their action that explains the appearance of hair on the pubis and armpits, and the increased growth of girls during puberty.

In recent years, new mechanisms for the formation and regulation of reproductive function have been discovered. The leading place is given to brain neurotransmitters (catecholamines, serotonin, GABA, glutamic acid, acetylcholine, enkephalins), which regulate the development and functioning of the hypothalamus (secretion and rhythmic release of liberins and statins) and the gonadotropic function of the pituitary gland. The role of catecholamines has been most studied: thus, norepinephrine activates, and dopamine suppresses the secretion of luliberin and the release of prolactin in hyperprolactinemia.

Neurotransmitter mechanisms, and primarily the sympathoadrenal system, provide a circhoral (within an hour) rhythm of the release of hormones from the hypothalamus and pituitary gland and circadian fluctuations in the level of gonadal hormones according to the phases of the menstrual cycle. Circadian fluctuations in hormone levels determine the body's hormonal homeostasis.

Important role in the regulation of reproductive function belongs to endogenous opiates (enkephalins and their derivatives, pre- and proenkephalins - leumorphine, neoendorphins, dynorphin), which have a morphine-like effect and were isolated in the central and peripheral structures of the nervous system in the mid-1970s 0. Hughes, 197 5). Endogenous opiates stimulate the secretion of prolactin and growth hormone, inhibit the production of ACTH and LH, and sex hormones affect the activity of endogenous opiates.

The latter are found in all areas of the central nervous system, in the peripheral nervous system, spinal cord, hypothalamus, pituitary gland, peripheral endocrine glands, gastrointestinal tract, placenta, sperm, and in follicular and peritoneal fluid their amount is 10-40 times higher than in blood plasma, which suggests their local production (V.P. Smetniks et al., 1997). Endogenous opiates, sex steroid hormones, hormones of the pituitary gland and hypothalamus interconnectedly regulate reproductive function. In this relationship, the most important role is played by catecholamines, which was established by the example of dopamine blockade of the synthesis and release of prolactin. Data on the role of neurotransmitters and the influence of endogenous opiates through them on the regulation of reproductive function open up new opportunities to substantiate the development of various variants of pathology of reproductive function and, accordingly, pathogenetic therapy using endogenous opiates or their already known antagonists (nalokean and naltrexone).

Along with neurotransmitters, an important place in the neuroendocrine homeostasis of the body is given to the pineal gland, which was previously considered an inactive gland. It secretes monoamines and oligopeptide hormones. The role of melatonin has been most studied. The influence of this hormone on the hypothalamic-pituitary system, the formation of gonadotropins and prolactin is known.

Role pineal gland in the regulation of reproductive function is indicated both for physiological (formation and development, menstrual function, labor, lactation) and pathological (menstrual dysfunction, infertility, neuro-endocrine syndromes) conditions.

Thus, regulation of puberty and development of reproductive function carried out by a single complex functional system, including the higher parts of the central nervous system (hypothalamus, pituitary gland and pineal gland), peripheral endocrine glands (ovaries, adrenal glands and thyroid gland), as well as the female genital organs. In the process of interaction of these structures, the development of secondary sexual characteristics and the formation of menstrual function occur.

Stages of development secondary sexual characteristics and the menstrual cycle have certain characteristics. Sexual development determined by the severity of the following indicators: Ma - mammary glands, P - pubic hair, Ax - armpit hair, Me - age of first menstruation and the nature of menstrual function. Each sign is determined in points that characterize the degree (stage) of its development.

The first menstruation appears at the age of 11 - 15 years. At the age of menarche, heredity, climate, as well as living and nutritional conditions play a certain role. These same factors influence puberty in general. IN Lately The world has seen an acceleration in the physical and sexual development of children and adolescents (acceleration), which is due to urbanization, improved living conditions, and widespread participation of the population in physical education and sports.

If secondary sexual characteristics and the first menstruation appear in girls after 15 years of age, then delayed puberty occurs or various deviations of sexual development and the formation of generative function are noted. The appearance of menarche and other signs of puberty before the age of 10 characterizes precocious puberty.

Signs of puberty are assessed in points: Ma - 0-4; P - 0-3; Ah - 0-3; Me - 0-3.

Ma0- the mammary gland is not enlarged, the nipple is small, not pigmented. Ma - the gland is slightly enlarged, protrudes above the surface of the body, the nipple is swollen, enlarged in size, not pigmented.

Ma2- a conical gland with an enlarged nipple without pigmentation around it. Ma - a round breast with a nipple raised above it and a pigmented circle around it. Ma4 - breast shapes and sizes characteristic of an adult woman.

P 0- no hair, P, - single straight hair appears, P2 - thick and long hair in the central part of the pubis, P, - thick and curly hair in the area of ​​the entire triangle and labia.

Ah0- lack of hair, Ah, - single hair, Ah2 - thick and long hair in the middle part of the armpit, Ah, - thick, long, curly hair throughout the armpit.

Me0- absence of menstruation, Me, - menstruation in the year of examination, Me2 - irregular menstruation, Me3 - regular, with a certain rhythm of menstruation.

To assess puberty and its disorders, the severity of hair growth on the skin of other locations is determined: upper lip, chin, chest, upper and lower half of the back and abdomen, shoulder, forearm, thigh and lower leg.

The severity of hair growth in these places is assessed on a 4-point scale:

1 - individual scattered hairs,

2 - moderate scattered hair growth,

3 - moderate continuous or diffuse total hair growth,

4 - intense continuous hair growth.

The sum of the hairiness scores of the forearms and legs is the indifferent number (IN), and for all other parts of the body - the hormonal number (HN). The sum of the HI and HF forms the hirsut number, which on average is 4-5 points with the standard being less than 10-12. A higher number of points for these indicators indicates hormonal disorders.

Approximate standards for puberty of girls by age: 10-12 years old Po Ax0 Ma, - P2 Ax2 Ma2, 13-14 years P2 Ax2 Ma2 Me, - P, Ax3Ma5Me, 15-16 years P, Ax3Ma, Me3.

Throughout her life, a woman goes through a wonderful journey from a girl to a woman capable of giving life to another person. It is the stage when this ability can and should be used that is called childbearing. A woman's reproductive age is assessed differently in different countries and by different experts. But there is unity in one thing - the opinion that a woman should give birth from 20 to 35 is supported everywhere. It is optimal to give birth to your first child before the age of 25-27, when the body is already fully mature and ready for bearing, but, at the same time, is not worn out.

It is believed that after 45-50 years, eggs stop being produced, as a result of which a woman’s ability to conceive disappears. However, in the world there are cases of children being born to women over 50 years of age. This is largely facilitated by modern technology.

Childbearing age - early and late pregnancy

It is believed that early pregnancy is dangerous for both the woman and the baby she is carrying. Mothers who are too young have an increased risk of spontaneous miscarriage, bleeding and toxicosis. Babies born to mothers who have not yet turned 20 years old are often underweight, do not gain weight well after birth, and do not adapt well to new conditions for them. In addition, the girl may not be psychologically ready for motherhood. She does not have all the necessary knowledge to implement proper care for the child.

If pregnancy is planned late, problems may arise with conception and pregnancy, because a woman aged 36 or more, as a rule, has certain diseases and health conditions that prevent her from conceiving or giving birth to a baby. In addition, after 40 years of age, there is a high probability of having a child with genetic disorders.

DMC of reproductive age

The question of a woman’s reproductive age is often associated with the question (DMK). Women are concerned about whether they are manifestations of menopause. According to statistics, DMC occurs in 4-5 women of reproductive age. They manifest themselves in the form of menstrual irregularities, when menstruation occurs after a significant delay or before the expected due date. Most often, the cause of DUB is a disruption of the ovaries. Other causes may include lung, kidney or liver disease. With DUB, ovulation does not occur, the corpus luteum does not form, and progesterone levels are reduced. All this makes it impossible to conceive a child. Typically, DUB occurs in women who have had abortions. ectopic pregnancy, infection or a disease of the endocrine system.

NMC in reproductive age

Menstrual irregularities (IMC) during the reproductive period are a common occurrence. NMCs include:

• amenorrhea – absence of menstruation;
• hypomenorrhea – scanty menstruation occurring on time;
• hypermenorrhea - too heavy menstruation that occurs on time;
• polymenorrhea – too long (6-8 days) menstruation;
• – periods are too short (1-2 days);
• tachymenorrhea – shortened menstrual cycle;
• opsomenorea – too infrequent menstruation (with a cycle of more than 35 days).

Reproductive age of women in different countries

In Russia and other European countries, there is an established opinion that a woman of reproductive age should be between 18 and 45 years old. During this period, it is believed that Slavic and European women can conceive and give birth to a child. At the same time, among women of southern national groups, reproductive age begins and ends much earlier. Eastern girls mature and get married early, and as mature women they age much faster. In Western European countries, the opposite trend is observed - towards a shift at a later date: childbirth well beyond 30 and even 40 years of age is considered normal, and accordingly, menopausal age is delayed, which is also facilitated by the widespread use of hormonal drugs.

How to extend a woman's reproductive age?

To extend their childbearing age, women need to closely monitor their health, treat any diseases in a timely manner, and monitor their hormonal levels. Preventing abortion is the key to prolonging the reproductive age.