Reproductive organs. Reproductive organs of the reproductive system Reproductive female and male reproductive organs

All methods of family planning, regardless of whether they are aimed at preventing pregnancy or ensuring its occurrence, are based on the information we have about the body’s ability to conceive (fertility). Natural methods are based on knowledge of physiological signs, allowing a married couple to determine the period when they should abstain from sexual intercourse if they are trying to avoid pregnancy, or engage in sexual intercourse if pregnancy is desired. To successfully use this method, it is necessary to have a good understanding of how the human reproduction process occurs and what are the signs of fertility in women.

Reproduction in humans

The process of reproduction begins with the fertilization of an egg by a sperm. After the egg is fertilized, it attaches to the uterine cavity and begins to develop.

Physiology of reproduction in men

After reaching puberty, a man's testicles begin to produce sperm, a process that continues throughout his life. During sexual intercourse, sperm in the seminal fluid travel from the penis into the woman's genital tract. In most cases, sperm remains viable for 24 to 120 hours. Millions of sperm are ejaculated at a time, but in order for any of them to reach the egg and fertilization occurs, a number of conditions are needed. It matters whether the sperm is able to pass through the woman’s reproductive tract to the egg, whether the liquid environment in them is sufficiently favorable, how quickly the sperm move, etc.

Physiology of reproduction in women

The ability of a woman's body to produce an egg and the possibility of pregnancy change cyclically every day. The first day of the cycle is considered the first day of menstruation.

At the beginning of each cycle, small structures called follicles mature in a woman's ovaries. The follicles produce the female sex hormone estrogen. Under the influence of accumulating estrogen in the body, glands located in the cervix (the lower part of the uterus that descends into the vagina) secrete a thin, viscous mucous lubricant, sometimes called fertile mucus, which a woman usually feels on her genitals several days before ovulation. When estrogen levels reach a maximum, one or sometimes several follicles rupture, releasing the egg. The life span of an egg is very short - usually about 12 hours, rarely more than a day. The egg passes into one of the fallopian tubes and enters the uterus. If, at the time the egg passes through the fallopian tube, there are healthy sperm in the latter, one of them can fertilize the egg. Under the influence of increased estrogen levels during the ovulation stage, the cervix becomes softer, takes a higher position in the vagina, moisturizes and opens. During this time, women experience lower abdominal pain and sometimes spotting or bleeding (called ovulatory or intermenstrual bleeding). If the egg is fertilized, it continues on its way to the uterus and attaches to the wall of its cavity.

After ovulation, the follicle that releases the egg turns into the corpus luteum, which secretes estrogen and progesterone. If fertilization has occurred, these two hormones hold the endometrium lining the uterine cavity in place, in which the fertilized egg is implanted. Under the influence of progesterone, cervical mucus turns from moist lubricant into a thick and sticky environment, and a woman may experience a feeling of dryness in the vulva area. Increasing levels of progesterone require an increase in basal body temperature (body temperature at rest) of at least 0.2 °C. If the egg is not fertilized, it disintegrates and estrogen and progesterone levels remain high for 10 to 16 days, after which they begin to decline. A decrease in the level of hormones in the blood leads to the rejection of the lining layer of the uterus, and menstruation occurs. The first day of menstruation is the first day of a new menstrual cycle. Typically, a woman's cycle lasts about 28-30 days, although in some cases it can be longer or shorter.

Thus, in a woman’s menstrual cycle there are three phases: 1) a relatively infertile (early infertile) phase, which begins simultaneously with menstruation; 2) the fertile phase, which includes the day of ovulation and those days immediately before and after ovulation during which sexual intercourse can lead to pregnancy; 3) postovulatory (late) infertile phase, which begins after the end of the fertile phase and lasts until the onset of menstruation.

The human body is a complex of physiological systems (nervous, cardiovascular, respiratory, digestive, excretory, etc.) that ensure the existence of a person as an individual. If any of them is violated, disorders occur that are often incompatible with life. The functions of the sexual or reproductive system are aimed primarily at the continued existence of humans as a biological species. All life-supporting systems function from birth to death; the reproductive system “works” only in a certain age period, corresponding to the optimal increase in physiological capabilities. This temporary conditionality is associated with biological expediency - bearing and raising offspring requires significant resources of the body. Genetically, this period is programmed for the age of 18–45 years.

Reproductive function is a complex of processes that covers the differentiation and maturation of germ cells, the process of fertilization, pregnancy, childbirth, lactation and subsequent care of the offspring. The interaction and regulation of these processes is ensured by a system whose center is the neuroendocrine complex: hypothalamus - pituitary gland - gonads. The reproductive, or genital, organs play a central role in the reproductive function. The genital organs are divided into internal and external.

Structure and age characteristics of the male reproductive system

In men, the internal genital organs include the gonads (testes with appendages), vas deferens, vas deferens, seminal vesicles, prostate gland and bulbourethral (Cooper's) glands; to the external genitalia - the scrotum and penis (Fig. 9.2).

Fig. 9.2.

Testicle – a paired male gonad that performs exocrine and endocrine functions in the body. The testicles produce sperm (external secretion) and sex hormones that influence the development of primary and secondary sexual characteristics (internal secretion). The shape of the testicle (testis) is an oval body, slightly compressed from the sides, lying in the scrotum. The right testicle is larger, heavier and located higher than the left one.

The testicles form in the abdominal cavity of the fetus and descend into the scrotum before birth (at the end of pregnancy). The movement of the testicles occurs along the so-called inguinal canal - an anatomical formation that serves to guide the testicles to the scrotum, and after the descent process is completed, to locate the vas deferens. The testicles, having passed the inguinal canal, descend to the bottom of the scrotum and are fixed there by the time the child is born. Undescended testicle (cryptorchidism) leads to disruption of its thermal regime, blood supply, and trauma, which contributes to the development of dystrophic processes in it and requires medical intervention.

In a newborn, the length of the testicle is 10 mm, weight - 0.4 g. Until puberty, the testicle grows slowly, and then its development accelerates. By the age of 14, it has a length of 20–25 mm and a weight of 2 g. At 18–20 years, its length is 38–40 mm, weight - 20 g. Later, the size and weight of the testicle increase slightly, and after 60 years they decrease slightly.

The testicle is covered with a dense connective tissue membrane, which forms a thickening at the posterior edge called mediastinum. Radial connective tissue septa extend from the mediastinum into the testicle, dividing the testis into many lobules (100–300). Each lobule includes 3–4 blindly closed convoluted seminiferous tubules, connective tissue and interstitial Leydig cells. Leydig cells produce male sex hormones, and the spermatogenic epithelium of the seminiferous tubules produces spermatozoa, consisting of a head, neck and tail. The convoluted seminiferous tubules become straight seminiferous tubules, which open into the ducts of the testicular network located in the mediastinum. In a newborn, convoluted and straight seminiferous tubules do not have a lumen - it appears during puberty. In adolescence, the diameter of the seminiferous tubules doubles, and in adult men it triples.

Efferent tubules (15–20) emerge from the testicular network, which, twisting strongly, form cone-shaped structures. The combination of these structures is the epididymis, adjacent to the upper pole and posterolateral edge of the testicle; it contains the head, body, and tail. The epididymis of a newborn is large, its length is 20 mm, its weight is 0.12 g. During the first 10 years, the epididymis grows slowly, and then its growth accelerates.

In the area of ​​the body of the epididymis, the efferent tubules merge into the epididymal duct, which passes into the area of ​​the tail into vas deferens , which contains mature but immobile sperm, has a diameter of about 3 mm and reaches a length of 50 cm. Its wall consists of mucous, muscular and connective tissue membranes. At the level of the lower pole of the testicle, the vas deferens turns upward and, as part of the spermatic cord, which also includes vessels, nerves, membranes and the muscle that lifts the testicle, follows to the inguinal canal into the abdominal cavity. There it separates from the spermatic cord and, without passing through the peritoneum, descends into the pelvis. Near the bottom of the bladder, the duct expands, forming an ampulla, and, having accepted the excretory ducts of the seminal vesicles, continues as ejaculatory duct. The latter passes through the prostate gland and opens into the prostatic part of the urethra.

In a child, the vas deferens is thin, its longitudinal muscular layer appears only by the age of 5. The muscle that lifts the testicle is poorly developed. The diameter of the spermatic cord in a newborn is 4.5 mm, at 15 years old - 6 mm. The spermatic cord and vas deferens grow slowly until the age of 14–15 years, and then their growth accelerates. Spermatozoa, mixing with the secretions of the seminal vesicles and prostate gland, acquire the ability to move and form seminal fluid (sperm).

Seminal vesicles They are a paired oblong organ, about 4–5 cm long, located between the bottom of the bladder and the rectum. They produce a secretion that is part of the seminal fluid. The seminal vesicles of a newborn are poorly developed, with a small cavity, only 1 mm long. Until 12–14 years of age, they grow slowly; at 13–16 years of age, growth accelerates, and the size and cavity increase. At the same time, their position also changes. In a newborn, the seminal vesicles are located high (due to the high position of the bladder) and are covered on all sides by the peritoneum. By the age of two, they descend and lie retroperitoneally.

Prostate gland (prostate) ) is located in the pelvic area under the bottom of the bladder. Its length in an adult man is 3 cm, weight is 18–22 g. The prostate consists of glandular and smooth muscle tissue. The glandular tissue forms lobules of the gland, the ducts of which open into the prostatic part of the urethra. The mass of the prostate gland in a newborn is about

0.82 g, at 3 years – 1.5 g, after 10 years, accelerated growth of the gland is observed and by the age of 16 its weight reaches 8–10 g. The shape of the gland in a newborn is spherical, since the lobules are not yet expressed, it is located high, It has a soft consistency and lacks glandular tissue. By the end of puberty, the internal opening of the urethra shifts to its anterior-superior edge, glandular parenchyma and prostatic ducts are formed, and the gland acquires a dense consistency.

Bulbourethral (Cooper's gland - a paired organ the size of a pea - located in the urogenital diaphragm. Its function is to secrete a mucous secretion that promotes the movement of sperm through the urethra. Its excretory duct is very thin, 3–4 cm long, and opens into the lumen of the urethra.

Scrotum is a receptacle for the testicles and appendages. In a healthy man, it contracts due to the presence of muscle cells – myocytes – in its walls. The scrotum is like a “physiological thermostat” that maintains the temperature of the testicles at a lower level than body temperature. This is a necessary condition for the normal development of sperm. A newborn's scrotum is small in size, and intensive growth is observed during puberty.

Penis has a head, neck, body and root. The glans is the thickened end of the penis, at which the external opening of the urethra opens. Between the head and the body of the penis there is a narrowed part - the neck. The root of the penis is attached to the pubic bones. The penis consists of three cavernous bodies, two of which are called the corpora cavernosa of the penis, the third is called the corpus spongiosum urethra (the urethra passes through it). The anterior section of the corpus spongiosum is thickened and forms the glans penis. Each corpus cavernosum is covered on the outside with a dense connective tissue membrane, and on the inside has a spongy structure: thanks to numerous partitions, small cavities (“caves”) are formed, which during sexual intercourse are filled with blood, the penis swells and becomes erect. The length of the penis in a newborn is 2–2.5 cm, the foreskin is long and completely covers its head (phimosis). In children of the first years of life, the state of phimosis is physiological, but with pronounced narrowing, swelling of the foreskin may be observed, leading to difficulty urinating. Under the foreskin, a whitish sebaceous substance (smegma) accumulates, produced by glands located on the head of the penis. If personal hygiene is not observed and an infection occurs, smegma decomposes, causing inflammation of the head and foreskin.

Before puberty, the penis grows slowly, and then its growth accelerates.

Spermatogenesis – the process of development of male reproductive cells, ending with the formation of sperm. Spermatogenesis begins under the influence of sex hormones during puberty in adolescence and then proceeds continuously, and in most men almost until the end of life.

The process of sperm maturation occurs inside the convoluted seminiferous tubules and lasts on average 74 days. On the inner wall of the tubules there are spermatogonia (the earliest, first cells of spermatogenesis), containing a double set of chromosomes. After a series of successive divisions, during which the number of chromosomes in each cell is halved, and after a long differentiation phase, spermatogonia turn into spermatozoa. This happens by gradually stretching the cell, changing and lengthening its shape, as a result of which the cell nucleus forms the head of the sperm, and the membrane and cytoplasm form the neck and tail. Each sperm carries half a set of chromosomes, which, when combined with a female reproductive cell, will give the full set necessary for the development of the embryo. After this, mature sperm enter the lumen of the testicular tubule and then into the epididymis, where they accumulate and are excreted from the body during ejaculation. 1 ml of sperm contains up to 100 million sperm.

A mature normal human sperm consists of a head, neck, body and tail, or flagellum, which ends in a thin terminal filament (Fig. 9.3). The total length of the sperm is about 50–60 µm (head 5–6 µm, neck and body 6–7 and tail 40–50 µm). The head contains the nucleus, which carries the paternal hereditary material. At its anterior end there is an acrosome, which ensures the penetration of sperm through the membranes of the female egg. The neck and body contain mitochondria and spiral filaments, which are the source of motor activity of the sperm. An axial filament (axoneme) extends from the neck through the body and tail, surrounded by a shell, under which 8–10 smaller fibrils are located around the axial filament, performing motor or skeletal functions in the cell. Motility is the most characteristic property of the sperm and is carried out with the help of uniform blows of the tail by rotating around its own axis in a clockwise direction. The duration of sperm existence in the vagina reaches 2.5 hours, in the cervix - 48 hours or more. Normally, the sperm always moves against the flow of fluid, which allows it to move upward at a speed of 3 mm/min along the female reproductive tract before meeting the egg.

Human reproduction

Human reproduction (human reproduction), a physiological function necessary for the preservation of humans as a biological species. The process of reproduction in humans begins with conception (fertilization), i.e. from the moment of penetration of the male reproductive cell (sperm) into the female reproductive cell (egg, or ovum). The fusion of the nuclei of these two cells is the beginning of the formation of a new individual. A human embryo develops in a woman's uterus during pregnancy, which lasts 265–270 days. At the end of this period, the uterus begins to spontaneously contract rhythmically, contractions become stronger and more frequent; the amniotic sac (fetal sac) ruptures and, finally, the mature fetus is “expelled” through the vagina - a child is born. Soon the placenta (afterbirth) also leaves. The entire process, starting with uterine contractions and ending with the expulsion of the fetus and placenta, is called childbirth.

In more than 98% of cases, during conception, only one egg is fertilized, which causes the development of one fetus. Twins (twins) develop in 1.5% of cases. About one in 7,500 pregnancies result in triplets.

Only biologically mature individuals have the ability to reproduce. During puberty (puberty), a physiological restructuring of the body occurs, manifested in physical and chemical changes that mark the onset of biological maturity. During this period, the girl’s fat deposits around the pelvis and hips increase, the mammary glands grow and become round, and hair growth develops on the external genitalia and armpits. Soon after the appearance of these so-called secondary sexual characteristics, the menstrual cycle is established.

Boys' physique changes noticeably during puberty; the amount of fat on the stomach and hips decreases, the shoulders become wider, the timbre of the voice decreases, and hair appears on the body and face. Spermatogenesis (production of sperm) in boys begins somewhat later than menstruation in girls.

Female reproductive system

Reproductive organs. The female internal reproductive organs include the ovaries, fallopian tubes, uterus, and vagina.

The ovaries - two glandular organs weighing 2-3.5 g each - are located behind the uterus on both sides. In a newborn girl, each ovary contains an estimated 700,000 immature eggs. All of them are enclosed in small round transparent sacs - follicles. The latter ripen one by one, increasing in size. The mature follicle, also called the Graafian vesicle, ruptures, releasing the egg. This process is called ovulation. The egg then enters the fallopian tube. Typically, during the entire reproductive period of life, approximately 400 eggs capable of fertilization are released from the ovaries. Ovulation occurs monthly (around the middle of the menstrual cycle). The burst follicle sinks into the thickness of the ovary, is overgrown with scar connective tissue and turns into a temporary endocrine gland - the so-called. corpus luteum, which produces the hormone progesterone.

The fallopian tubes, like the ovaries, are paired formations. Each of them extends from the ovary and connects to the uterus (from two different sides). The length of the pipes is approximately 8 cm; they bend slightly. The lumen of the tubes passes into the uterine cavity. The walls of the tubes contain inner and outer layers of smooth muscle fibers, which constantly contract rhythmically, which ensures the wave-like movements of the tubes. The inside walls of the tubes are lined with a thin membrane containing ciliated (ciliated) cells. Once the egg enters the tube, these cells, along with muscle contractions of the walls, ensure its movement into the uterine cavity.

The uterus is a hollow muscular organ, 2.55located in the pelvic abdominal cavity. Its dimensions are approximately 8 cm. Pipes enter into it from above, and from below its cavity communicates with the vagina. The main part of the uterus is called the body. The non-pregnant uterus has only a slit-like cavity. The lower part of the uterus, the cervix, is about 2.5 cm long, protruding into the vagina, into which a cavity called the cervical canal opens. When a fertilized egg enters the uterus, it is immersed in its wall, where it develops throughout pregnancy.

The vagina is a hollow cylindrical formation 7–9 cm long. It is connected to the cervix along its circumference and extends to the external genitalia. Its main functions are the outflow of menstrual blood, the reception of the male sexual organ and male seed during copulation, and the provision of passage for the newborn fetus. In virgins, the external opening to the vagina is partially covered by a crescent-shaped fold of tissue, the hymen. This fold usually leaves enough space for the flow of menstrual blood; After the first copulation, the vaginal opening widens.

Mammary gland. Full-fledged (mature) milk in women usually appears approximately 4–5 days after birth. When a baby suckles at the breast, there is an additional powerful reflex stimulus to the glands producing milk (lactation).

The menstrual cycle is established soon after the onset of puberty under the influence of hormones produced by the endocrine glands. In the early stages of puberty, pituitary hormones initiate the activity of the ovaries, triggering a complex of processes that occur in the female body from puberty to menopause, i.e. for approximately 35 years. The pituitary gland cyclically secretes three hormones that are involved in the process of reproduction. The first, follicle-stimulating hormone, determines the development and maturation of the follicle; the second - luteinizing hormone - stimulates the synthesis of sex hormones in the follicles and initiates ovulation; the third - prolactin - prepares the mammary glands for lactation.

Under the influence of the first two hormones, the follicle grows, its cells divide, and a large fluid-filled cavity is formed in which the oocyte is located. The growth and activity of follicular cells is accompanied by the secretion of estrogens, or female sex hormones. These hormones can be found both in follicular fluid and in the blood. The term estrogen comes from the Greek oistros (“fury”) and is used to refer to a group of compounds that can cause estrus (“estrus”) in animals. Estrogens are present not only in the human body, but also in other mammals.

Luteinizing hormone stimulates the follicle to rupture and release the egg. After this, the follicle cells undergo significant changes, and a new structure develops from them - the corpus luteum. Under the influence of luteinizing hormone, it, in turn, produces the hormone progesterone. Progesterone inhibits the secretory activity of the pituitary gland and changes the state of the mucous membrane (endometrium) of the uterus, preparing it to receive a fertilized egg, which must penetrate (implantate) into the wall of the uterus for subsequent development. As a result, the wall of the uterus thickens significantly, its mucous membrane, containing a lot of glycogen and rich in blood vessels, creates favorable conditions for the development of the embryo. The coordinated action of estrogen and progesterone ensures the formation of the environment necessary for the survival of the embryo and the maintenance of pregnancy.

The pituitary gland stimulates ovarian activity approximately every four weeks (ovulatory cycle). If fertilization does not occur, most of the mucous membrane, along with the blood, is rejected and enters the vagina through the cervix. Such cyclically repeating bleeding is called menstruation. For most women, bleeding occurs approximately every 27–30 days and lasts 3–5 days. The entire cycle that ends with the shedding of the uterine lining is called the menstrual cycle. It is regularly repeated throughout the reproductive period of a woman’s life. The first periods after puberty may be irregular, and in many cases they are not preceded by ovulation. Menstrual cycles without ovulation, often found in young girls, are called anovulatory.

Menstruation is not at all the release of “spoiled” blood. In fact, the discharge contains very small amounts of blood mixed with mucus and tissue from the lining of the uterus. The amount of blood lost during menstruation varies from woman to woman, but on average does not exceed 5–8 tablespoons. Sometimes minor bleeding occurs in the middle of the cycle, which is often accompanied by mild abdominal pain, characteristic of ovulation. Such pains are called mittelschmerz (German: “middle pains”). Pain experienced during menstruation is called dysmenorrhea. Typically, dysmenorrhea occurs at the very beginning of menstruation and lasts 1–2 days.

Pregnancy. In most cases, the release of the egg from the follicle occurs approximately in the middle of the menstrual cycle, i.e. 10–15 days after the first day of the previous menstruation. Within 4 days, the egg moves through the fallopian tube. Conception, i.e. Fertilization of an egg by a sperm occurs in the upper part of the tube. This is where the development of the fertilized egg begins. Then it gradually descends through the tube into the uterine cavity, where it remains free for 3-4 days, and then penetrates the wall of the uterus, and from it the embryo and structures such as the placenta, umbilical cord, etc. develop.

Pregnancy is accompanied by many physical and physiological changes in the body. Menstruation stops, the size and weight of the uterus sharply increase, and the mammary glands swell, preparing for lactation. During pregnancy, the volume of circulating blood exceeds the original by 50%, which significantly increases the work of the heart. In general, the pregnancy period is a heavy physical activity.

Pregnancy ends with the expulsion of the fetus through the vagina. After childbirth, after about 6 weeks, the size of the uterus returns to its original size.

Menopause. The term "menopause" is made up of the Greek words meno ("monthly") and pausis ("cessation"). Thus, menopause means the cessation of menstruation. The entire period of decline of sexual functions, including menopause, is called menopause.

Menstruation also stops after surgical removal of both ovaries, performed for certain diseases. Exposure of the ovaries to ionizing radiation can also lead to cessation of their activity and menopause.

About 90% of women stop menstruating between the ages of 45 and 50. This can happen abruptly or gradually over many months, when menstruation becomes irregular, the intervals between them increase, the bleeding periods themselves gradually shorten and the amount of blood lost decreases. Sometimes menopause occurs in women under 40 years of age. Equally rare are women with regular menstruation at 55 years of age. Any bleeding from the vagina that occurs after menopause requires immediate medical attention.

Symptoms of menopause. During the period of cessation of menstruation or immediately before it, many women develop a complex set of symptoms that together constitute the so-called. menopausal syndrome. It consists of various combinations of the following symptoms: “hot flashes” (sudden redness or a feeling of heat in the neck and head), headaches, dizziness, irritability, mental instability and joint pain. Most women only complain about hot flashes, which can occur several times a day and are usually more severe at night. Approximately 15% of women do not feel anything, noting only the cessation of menstruation, and remain in excellent health.

Many women have misconceptions about what to expect during menopause and menopause. They are worried about the possibility of loss of sexual attractiveness or sudden cessation of sexual activity. Some fear mental illness or general decline. These fears are based primarily on rumors rather than medical facts.

Male reproductive system

The reproductive function in men is reduced to the production of a sufficient number of sperm that have normal motility and are capable of fertilizing mature eggs. The male genital organs include the testes (testes) with their ducts, the penis, and an auxiliary organ, the prostate gland.

Testicles (testes, testicles) are oval-shaped paired glands; each of them weighs 10–14 g and is suspended in the scrotum on the spermatic cord. The testicle consists of a large number of seminiferous tubules, which, merging, form the epididymis - epididymis. This is an oblong body adjacent to the top of each testicle. The testicles secrete male sex hormones, androgens, and produce sperm containing male reproductive cells - sperm.

Spermatozoa are small, very motile cells, consisting of a head containing a nucleus, a neck, a body and a flagellum or tail. They develop from special cells in thin convoluted seminiferous tubules. Maturing spermatozoa (so-called spermatocytes) move from these tubules into larger ducts that flow into spiral tubes (efferent, or excretory, tubules). From these, spermatocytes enter the epididymis, where their transformation into sperm is completed. The epididymis contains a duct that opens into the vas deferens of the testicle, which, connecting with the seminal vesicle, forms the ejaculatory (ejaculatory) duct of the prostate gland. At the moment of orgasm, sperm, together with the fluid produced by the cells of the prostate gland, vas deferens, seminal vesicle and mucous glands, are released from the seminal vesicle into the ejaculatory duct and then into the urethra of the penis. Normally, the volume of ejaculate (semen) is 2.5–3 ml, and each milliliter contains more than 100 million sperm.

Fertilization. Once in the vagina, sperm move into the fallopian tubes in about 6 hours using the movements of the tail, as well as due to the contraction of the vaginal walls. The chaotic movement of millions of sperm in the tubes creates the possibility of their contact with the egg, and if one of them penetrates it, the nuclei of the two cells merge and fertilization is completed.

Infertility

Infertility, or the inability to reproduce, can be due to many reasons. Only in rare cases is it caused by the absence of eggs or sperm.

Female infertility. A woman’s ability to conceive is directly related to her age, general health, stage of the menstrual cycle, as well as her psychological mood and lack of nervous tension. Physiological causes of infertility in women include lack of ovulation, unresponsiveness of the endometrium of the uterus, genital tract infections, narrowing or blockage of the fallopian tubes, and congenital abnormalities of the reproductive organs. Other pathological conditions can lead to infertility if left untreated, including various chronic diseases, nutritional disorders, anemia and endocrine disorders.

Diagnostic tests. Determining the cause of infertility requires a complete medical examination and diagnostic laboratory tests. The patency of the fallopian tubes is checked by blowing them. To assess the condition of the endometrium, a biopsy is performed (removal of a small piece of tissue) followed by microscopic examination. The function of the reproductive organs can be judged by analyzing the level of hormones in the blood.

Male infertility. If the semen sample contains more than 25% abnormal sperm, fertilization is rare. Normally, 3 hours after ejaculation, about 80% of sperm retain sufficient mobility, and after 24 hours only a few of them show sluggish movements. Approximately 10% of men suffer from infertility due to insufficient sperm. Such men usually exhibit one or more of the following defects: a small number of sperm, a large number of abnormal forms, decreased or complete absence of sperm motility, and small ejaculate volume. The cause of infertility (sterility) may be inflammation of the testicles caused by mumps (mumps). If the testicles have not yet descended into the scrotum at the onset of puberty, the cells that make sperm may be permanently damaged. The outflow of seminal fluid and the movement of sperm are hindered by obstruction of the seminal vesicles. Finally, fertility (the ability to reproduce) may be reduced as a result of infectious diseases or endocrine disorders.

Diagnostic tests. In semen samples, the total number of sperm, the number of normal forms and their motility, as well as the volume of the ejaculate are determined. A biopsy is performed to examine the testicular tissue and the condition of the tubular cells microscopically. The secretion of hormones can be judged by determining their concentration in the urine.

Psychological (functional) infertility. Fertility is also affected by emotional factors. It is believed that a state of anxiety may be accompanied by a spasm of the tubes, which prevents the passage of the egg and sperm. Overcoming feelings of tension and anxiety in women in many cases creates the conditions for successful conception.

Treatment and research. Much progress has been made in the treatment of infertility. Modern methods of hormonal therapy can stimulate spermatogenesis in men and ovulation in women. With the help of special instruments, it is possible to examine the pelvic organs for diagnostic purposes without surgical intervention, and new microsurgical methods make it possible to restore the patency of pipes and ducts.

In vitro fertilization (in vitro fertilization). An outstanding event in the fight against infertility was the birth in 1978 of the first child developed from an egg fertilized outside the mother’s body, i.e. extracorporeally. This test tube child was the daughter of Leslie and Gilbert Brown, born in Oldham (UK). Her birth completed years of research work by two British scientists, gynecologist P. Steptoe and physiologist R. Edwards. Due to pathology of the fallopian tubes, the woman could not become pregnant for 9 years. To get around this obstacle, eggs taken from her ovary were placed in a test tube, where they were fertilized by adding her husband's sperm, and then incubated under special conditions. When the fertilized eggs began to divide, one of them was transferred to the mother's uterus, where implantation occurred and the natural development of the embryo continued. The baby, born by caesarean section, was normal in all respects. After this, in vitro fertilization (literally “in glass”) became widespread. Currently, similar assistance to infertile couples is provided in many clinics in different countries and as a result, thousands of “test tube” children have already appeared.

Freezing of embryos. Recently, a modified method has been proposed that has raised a number of ethical and legal issues: freezing fertilized eggs for later use. This technique, developed mainly in Australia, allows a woman to avoid having to undergo repeated egg retrieval procedures if the first attempt at implantation fails. It also makes it possible to implant an embryo into the uterus at the appropriate time in a woman's menstrual cycle. Freezing the embryo (at the very initial stages of development) and then thawing it also allows for successful pregnancy and childbirth.

Egg transfer. In the first half of the 1980s, another promising method of combating infertility was developed, called egg transfer, or in vivo fertilization - literally “in a living” (organism). This method involves artificial insemination of a woman who has agreed to become a donor with the sperm of the future father. After a few days, the fertilized egg, which is a tiny embryo (embryo), is carefully washed out of the donor's uterus and placed in the uterus of the expectant mother, who carries the fetus and gives birth. In January 1984, the first child born after an egg transfer was born in the United States.

Egg transfer is a non-surgical procedure; it can be done in a doctor's office without anesthesia. This method can help women who cannot produce eggs or have genetic disorders. It can also be used for tubal obstruction if a woman does not want to undergo the repeated procedures often required for in vitro fertilization. However, a child born in this way does not inherit the genes of the mother who carried him.

Bibliography

Bayer K., Sheinberg L. Healthy lifestyle. M., 1997

To prepare this work, materials from the site http://bio.freehostia.com were used

The biological species human, like other species of vertebrate animals, is divided into male and female individuals to ensure the sexual nature of reproduction, which gives genetic diversity to the offspring through a different combination of genes obtained from parental organisms; their reproductive organs are called reproductive organs. Male and female reproductive (genital) organs complement each other's functions during the reproduction process. As in other mammals, in humans, fertilization (and subsequent gestation of the embryo) is internal, occurring within the female internal genital organs, which explains the fact that the bulk of the female pelvic reproductive organs is internal (see Female Internal Genital Organs ). To carry out such fertilization, male representatives must have an organ external to the cavities of their body capable of penetrating into the fertilization zone - this is the male penis, the penis.

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Tasks of the reproductive system of men and women

The main task of the male reproductive system is the production of male gametes (sperm) and their delivery to the fertilization zone during sexual intercourse.

The tasks of the female reproductive system are more numerous. These include:

• production of female reproductive cells (eggs),
• delivering them to the fertilization zone,
• performing sexual acts,
• implementation of fertilization,
• carrying an embryo (fetus) throughout the entire period of pregnancy, ensuring its vital activity, protection and development to the extent that will allow it to live outside the mother’s body after birth;
• labor activity,
• production of breast milk for the entire period of feeding the baby.

Similar tasks in men and women are served by the functionally, and sometimes structurally, male and female genital organs:

• the production of germ cells and the secretion of hormones is carried out by the gonads (ovaries in women and testes in men);
• delivery of cells produced by the glands to the fertilization zone is carried out by the excretory ducts of the glands, which are hollow (tubular) organs - the vas deferens and the urethra in men and the fallopian tubes in women;
• sexual arousal and sensual satisfaction from sexual intercourse are provided by erogenous zones, rich in sensory nerve endings, of which the most specialized are those represented by the male penis, the penis, and the female clitoris, and especially by their outer extremities - the heads of the penis and the clitoris. (At the same time, there are differences: in addition to the genitals, the male penis also has the function of urination, and in order for it to go into erection mode to perform sexual intercourse and eject seminal fluid, it absolutely needs sexual stimulation, while the clitoris is an organ of exclusively erogenous sensuality, located outside direct passage of germ cells and is not involved in reproduction as such);
• protection of internal structures from undesirable influences of the external environment is provided by the integumentary elements of the reproductive system: the labia majora (external) and minora (internal) and the foreskin of the clitoris in women and the skin of the penis with its foreskin and the scrotum in men.

Relationship between the human reproductive system and other organ systems

Analogy between male (left) and female pelvic organs

The human reproductive system in representatives of both sexes is closely connected with the work of other organ systems and, above all, the endocrine system of the body, with which it has common elements, such as the gonads, which participate, together with other endocrine organs, in the production of hormones that regulate the body’s activities. The endocrine system ensures the process of puberty to enable reproductive function, supports the functioning of the reproductive organs during childbearing years and controls the decline of this function in old age.

Together with other endocrine glands, the sex glands participate in the formation of the entire appearance of a person through the production of hormones. Thus, men have on average higher height and muscle mass than women, which is determined by the development of the musculoskeletal system, differences in the proportions of the chest and pelvis areas, a slightly different nature of the distribution of fat and muscle tissue in the body, and a different nature of the distribution of hair. on the body. During the period of decline of reproductive function, women have a stronger and more frequent decrease in bone density than men and osteoporosis, which is dangerous for bone fractures.

The human reproductive system is connected to the urinary system, the lower part of which is also located in the pelvic region, although this connection is different in men and women. In women, the external opening of the urethra is located in the area of ​​the external genitalia (vulva), opening in the vestibule of the vagina, but the route of the canal runs separately from the genital tract (vagina), while in men, the release of both urine and seminal fluid occurs through the same duct - the urethra, which passes mostly inside the male penis. Due to pathological changes in the prostate gland that produces seminal fluid, associated with its growth, usually in old age, it, increasing in size, can compress the lumen of the urethra and make it difficult for men to urinate, while women, due to their shorter length and larger diameter, urethra, which facilitate easier penetration of pathogenic bacteria, more often suffer from infectious and inflammatory diseases of the bladder (cystitis) and urethra (urethritis), associated with frequent urination and even incontinence.

Development of the human reproductive system. Its similarities and differences between men and women

Embryos in the initial periods of their development are not differentiated by sex and both the female and male reproductive systems are formed from the same previous embryonic structures, which leads to homology of structure and part of the functions between the male and female genital organs on the one hand (sex glands, excretory tubular organs, integumentary structures) - see List of homologous organs of the human reproductive system. With certain genetic failures, mutations, the sexual differentiation of the fetus and newborn may be disrupted, and then its genital organs will either have an appearance intermediate between those characteristic of normal development according to the male or female type, or will not correspond to the properties of its internal genital organs (external organs of the male type, and internal female and vice versa); such disorders are called hermaphroditism or intersexuality.

The largest part of the human reproductive system is located in the pelvic region - the lower part of the body, while the mammary glands necessary for feeding a born child are located on the upper half of the body - the chest.

Under the influence of specific hormones, the mammary glands normally develop and can fully function, producing breast milk, only in females, and in males, in the absence of a specific hormonal pathology (gynecomastia), they remain in an undeveloped, rudimentary state.

On the contrary, among the pelvic reproductive organs, the external genitalia in men receive comparatively greater development and size under the influence of male sex hormones. The male penis, as necessary for internal fertilization, becomes several times larger in length and width than its homologue in women, which is not intended for this purpose - the clitoris, and the fused folds of skin under the penis form the scrotum, into which in boys the gonads protected by it normally descend (testes), while the female gonads (ovaries) do not emerge from the pelvic cavity into the labia majora corresponding to the scrotum, which cover and protect the entire area of ​​the genital slit. The embryonic urogenital groove should close in boys, and in girls it should form a genital fissure with the vestibule of the vagina, containing the external openings of the vagina and the female urethra, covered by the labia minora and majora.

With various genetic and hormonal disorders, the appearance and structural elements of the male and female genital organs can become closer, in particular due to hormonal imbalance. The gonads of both women and men produce both female and male sex hormones, but in different ratios characteristic of each sex, and if these ratios are violated, then feminization of men or masculinization of women can occur, that is, a change in their primary and secondary sexual characteristics in in a direction opposite to the nature of their gonads. Thus, the penis may appear too small and underdeveloped (micropenia), while the clitoris may be unusually enlarged (clitoromegaly). The urogenital groove in boys may not be sufficiently closed and the urethra and part of their penis may be split, and the external opening of the canal may be lower than usual, while in girls there are fusions (adhesions, synechiae) of the labia. The testicles, like the ovaries, may not descend into the scrotum. Some of these phenomena may be transient, temporary, for example, when female bodybuilders take hormonal stimulants.

The reproductive function of humans is less seasonal than that of many other species. However, in women, unlike men, its implementation is periodic, associated with the alternate maturation and release of female germ cells. During the reproductive period of a woman’s life, it occurs monthly. If such a cell is fertilized, pregnancy occurs, otherwise the inner layer of the uterus is renewed and the old epithelium with blood is released through the vagina to the outside, which represents menstruation. This constitutes a woman's menstrual cycle.

Exercising reproductive function

Human reproduction occurs as a result of internal fertilization, which completes sexual intercourse:

• During sexual intercourse, the man's erect penis is inserted into the woman's vagina. At the end of sexual intercourse, ejaculation occurs - the release of sperm from the penis into the vagina.
• The sperm contained in semen move through the vagina towards the uterus or fallopian tubes to fertilize an egg.
• After successful fertilization and implantation of the zygote, development of the human embryo occurs in the woman's uterus for approximately nine months. This process is called pregnancy, which ends in childbirth.
• During labor, the muscles of the uterus contract, the cervix dilates, and the fetus is pushed out of the uterus.
• Infants and children are virtually helpless and require parental care for many years. During the first year of life, a woman usually uses the mammary glands located in her breasts to feed her baby.

Humans, as one of the biological species, are characterized by a high degree of sexual dimorphism. In addition to the difference in primary sexual characteristics (genitals), there are differences in secondary sexual characteristics and sexual behavior.

Male reproductive system

Labia minora

Unlike the male penis, which has two longitudinal corpora cavernosa at the top and a corpus spongiosum at the bottom, which extends into the glans penis and contains the male urethra, the clitoris contains only the corpora cavernosa and does not usually have a urethra running through it.

A very large number of nerve endings contained in clitoris, as well as in labia minora react to irritation of an erotic nature, therefore stimulation (stroking and similar actions) of the clitoris can lead to sexual arousal of a woman.

Behind (below) the clitoris is the external opening of the urethra (urethra). In women, it serves only to remove urine from the bladder. Above the clitoris itself in the lower abdomen there is a small thickening of adipose tissue, which in adult women is covered with hair. It's called tubercle of venus.

Diseases of the human reproductive system

Like other complex organ systems, the human reproductive system is affected by a large number of diseases. There are four main categories of diseases:

• congenital or congenital;
• infections, often sexually transmitted;
• functional impairment caused by environmental factors, injury, psychosomatic factors and autoimmune diseases. The most well-known type of functional disorder is infertility, which can be caused by many diseases.

Congenital anomalies

Congenital defects include malformations of the reproductive organs, which may in the present or future lead to disruptions in their functioning to varying degrees, and their early detection is an important medical task.

Thus, after the birth of a child or even during intrauterine diagnosis, the need arises to determine his sex, which becomes difficult in cases of insufficient differentiation of his external genitalia according to the male or female type or the discrepancy between their structure and the type of gonads. Then we can talk about hermaphroditism

Female reproductive system– a closely connected complex of internal/external organs of the female body, primarily responsible for the reproductive function. This complex includes the genitals, as well as the mammary glands, which are connected with the former on a functional, rather than an anatomical level. A woman's reproductive system is immature after birth and develops before reaching maturity during puberty (puberty), gaining the ability to produce female gametes (eggs) and carry a fetus to full term.

Formation of a woman's reproductive system

Chromosomal characteristics determine the genetic sex of the fetus at the time of conception. Twenty-three pairs of chromosomes, which are inherited, form the basis of this concept. Since the mother's egg contains X chromosomes, and the father's sperm contains two different chromosomes - X or Y, it is the man who determines the sex of the fetus:

• The fetus will be female if it inherits the X chromosome from the father. In this situation, testosterone will not be synthesized, so the Wolffian canal (male urogenital structure) will begin to degrade, and the Müllerian duct (female urogenital structure) will transform into female genitalia. In the third month of the embryo’s life, the formation of the vagina and uterine organ begins, and approximately in the fifth or sixth month the vaginal lumen is formed. The clitoris is a remnant of the Wolffian canal, and the hymen is a remnant of the Müllerian duct.
• If the fetus inherits a Y chromosome from its father, it will be male. The presence of testosterone will stimulate the growth of the Wolffian canal, which will lead to the development of male genitalia. The Müllerian course, in turn, will degrade.

Reproductive organs are formed in the womb and their subsequent development occurs as the child grows. The process of puberty begins in adolescence, the key signs of which are:

• enlargement of the pelvic area;
• the beginning of menstruation;
• hair growth in the pubic area and armpits;
• maturation of female gametes.
• Puberty results in sexual maturity, that is, the ability to bear and give birth to children. The childbearing period is usually limited in time. After its completion, the menstrual cycle stops and menopause develops, lasting until death.

Female reproductive system: functions

The female reproductive system is designed to perform a number of functions. Firstly, it produces eggs and ensures their transportation to the site of fertilization by sperm. Conception, i.e. Fertilization of the female gamete by the male usually occurs inside the fallopian tubes. Secondly, the reproductive system ensures the implantation of the embryo into the uterine wall, this occurs in the early stages of pregnancy. Thirdly, it is intended for menstruation (in the absence of fertilization/implantation of the embryo). Finally, the female reproductive system produces sex hormones that are required to support the reproductive cycle.

Internal organs of the female reproductive system

They are located in the lower part of the pelvic cavity, that is, inside the small pelvis.

Vagina

The vagina is a muscular-elastic canal that connects the cervix (aka the cervix - the lower element of the uterine organ) and the external part of the body. In virgins, the vagina is closed by the hymen. In relation to the uterus, it forms an angle that is open in front.

Uterus

The smooth muscle organ of the woman’s reproductive system, where the embryo develops and the fetus is born. It is divided into 3 parts - the bottom, the body (corpus) and the cervix. The body is able to expand significantly to accommodate the growing fetus. The cervix allows sperm to pass in and allows menstrual blood to pass out.

Ovaries

Small paired glands, oval-shaped and located on each side of the uterus. The basic tasks of the ovaries are generative and endocrine: generative - the ovaries serve as the site of development/maturation of female gametes; endocrine – these organs produce sex hormones, namely estrogens, weak progestins and androgens.

Fallopian tubes

Narrow tubes that are attached to the top of the uterus. They act as a tunnel for eggs moving from the ovaries into the uterine organ. This is where conception usually occurs. Then, thanks to the movements of the ciliated epithelial tissue of the tubes, the fertilized (or unfertilized) female gamete is sent to the uterus.

Hymen

The hymen (hymen) is a thin fold of mucous membrane that has one or several small holes. It covers the outside of the genital slit. The holes allow secretions to escape. During the first coitus, the hymen, as a rule, is completely or partially destroyed (so-called defloration), and after childbirth it is almost not preserved.

External organs of the female reproductive system

Have two key tasks:

• allow sperm to enter the body;
• protect the internal genital organs from all kinds of infections.

Labia

Two pairs of folds of mucous membrane and skin that surround the genital slit on the sides and go from the pubis towards the anus. The labia majora and minora are divided into:

• Large (labia majora) - larger and fleshier, comparable to the scrotum in males. They contain the exocrine glands (sweat and sebaceous), cover and protect other external reproductive organs.
• Small (labia minora) - can be small in size or reach 50 mm in width. They are located inside the labia majora and directly surround the genital opening and urethral opening.

Bartholin's glands

Large paired glands located near the vaginal opening and secrete mucus that promotes normal coitus.

Clitoris

Two labia minora converge in the clitoris, a small anatomical formation with sensitive zones, which acts as an analogue, or more precisely, a homologue, of the penis in men. The clitoris is covered with a fold of skin called the prepuce, which is similar to the foreskin of the male organ. Similar to the penis, the clitoris is quite sensitive to sexual stimulation and is capable of achieving an erect state.

Women's reproductive rights

The International Federation of Gynecology and Obstetrics (FIGO) was created in the mid-1950s. to promote the well-being of women, especially increasing the level of gynecological care and care. Reproductive rights are the basic rights of women in the documents of this international public organization. They are associated with fertility and the health of the reproductive system. Women have the right to control issues related to their sexuality, including their sexual and reproductive health. Violations of these rights include: forced pregnancy, forced sterilization, forced