Gynecological physiology lecture
The ovaries have many follicles. The number of these follicles decreases very rapidly over time. As a fetus at the age of 20 weeks, the ovaries have 1.5 to 2 million primitive follicles
Gynaecological physiology studies all the problems related to changes in a woman's sexuality and sexual performance, mainly the functioning of the female genitals.
This is a very important part of gynaecology, contributing to understanding the basics of fertility and the causes of many gynaecological disorders and diseases.
The following features can be summarized:
The function of the female genitals is reproductive function, that is, the function of fertilization, implantation and development of eggs in the uterus.
All changes of the genitals are influenced by the endocrine axis of the hypothalamus-pituitary - ovary. This axis is cyclical, manifested by menstruation occurring every month, is the most obvious clinical sign.
The active relationships between the female genitals are often studied against a woman's menstruation and genital active life, arranged by periods: pre-puberty, puberty. then (when the first menstruation), the sexually active period (the menstrual period is instructed) and the menopause (stop menstruation) are based on menstruation.
The activity of the hypothalamus stimulates the pituitary gland. The work of the pituitary gland stimulates the ovaries. In return, the strong activity of the ovaries will inhibit the activity of the hypothalamus by the feed-back mechanism.
The genital centre of the hypothalamus lies in the base of the central brain, above the visual interference, consisting of a group of nerve nuclei rich in blood vessels, capable of secreting hormones. The nucleus secretes vasopressin, the side of the ventricle secretes oxytocin, which is led to the posterior pituitary by nerve fibres.
The gray bulb, the middle abdomen, the middle back and the bowler, secrete hormones to release. These hormones are transferred down the anterior pituitary gland (also called the pituitary gland) by a system of veins called the burden veins of Popa and Fielding. Among the above-said release hormones are sexually releasing hormones, called Gn-RH (Gonadotropin Releasing Hormone).
In 1971, Shaly synthesized LH-RH (LH-Kelcasing Hormone). It is a decapeptides that stimulates the pituitary to secrete LH. But since then, a second-stage release hormone, FSH-KH, as in the stated hypothesis has not been found. At the same time, LH-RH also stimulates the pituitary gland to secrete FSH. Therefore, in recent years, many agencies have referred to the LH-RH as Gn-RH. But there are other partners still keeping the old name LH-RH, although this substance has the ability to stimulate the pituitary gland to produce FSH as mentioned above.
The pituitary gland is located in the pituitary, weighing about 0.5 g, with two lobes. The anterior lobe is an endocrine gland, so it is also called adenohypophysis. The posterior lobe is a nerve-like tissue, also known as the neural pituitary (neurohypophysis), which is not the endocrine gland.
In terms of sexual activity, the anterior pituitary gland secretes gonadotropin hormones that stimulate the gonads, and at the same time, secretes prolactin that stimulates the mammary glands.
There are two gonadotropic hormones, FSH and LH. Both are glycoproteins.
FSH (Follicle Stimulating Hormone) stimulates ovarian follicles to develop and mature (ripening).
Luteinizing Hormone (LH) stimulates the mature oocyte to release, stimulates the formation of the corpus luteum and stimulates the release of the corpus luteum. Thus, the human LH is responsible for the LTH (Luteotropic Honoree) of some rodents.
Prolactin is a protein hormone that stimulates the mammary gland to release milk.
FSH and LH have nearly parallel menstrual cycle secretion curves and have a peak in the day before ovulation. However, the FSH nail is not as sudden as the LH peak, nor does it increase as much as the peak LH. On the day of ovulation, the LH peak sometimes reaches 5 to 10 times higher than before. In the second half of the cycle, the FSH value is slightly lower than in the first half of the cycle.
As noted above, a few days before oocyte proliferation can increase dramatically, reaching a peak 1 day before ovulation, then rapidly declining, down to the level before ovulation.
Ovaries are female gonads, usually have 2 ovaries, weighing 8 - 15 g. There are two functions: exocrine function to create a maturation and endocrine function to create sex hormones.
The ovaries have many follicles. The number of these follicles decreases very rapidly over time. As a fetus at the age of 20 weeks, the ovaries have 1.5 to 2 million primitive follicles. But when the baby girl is born, the number of follicles has decreased greatly, to about 200,000-300,000, which is about 10 times less in a 20-week period. At puberty, the number of follicles is reduced to 20,000-30,000. Although the rate of decline is slower, it is also a matter to think about the fate and ability of the remaining follicles. The decrease in the number of follicles is due to the shrinking of the degenerated follicles. But the remaining cysts are also on track to regress, albeit slowly, more slowly. If the ovules in these follicles are fertilized, the embryo formed may potentially be in danger of development.
The ovaries are incapable of producing new follicles, unlike the testes that are capable of producing new sperm, and the sperm is always young.
The original oocyte was 0.05 mm in diameter. Under the action of FSH, follicles grow and ripen. The mature oocyte, also known as a Graal cyst, is 1.5-2cm in diameter. The oocyte contained in this follicle also matures and is subject to a mitotic effect. Ripe ovule diameter 0.1 mm (100 micrometres)
Usually, only one follicle develops in each menstrual cycle to become a Graaf cyst. It is the most sensitive follicle in that cycle. This cyst develops from a growing follicle from the end of the previous menstrual cycle, not from a primitive follicle as the old theories have stated.
A matured follicle is a cavity follicle (hollow follicle) with the following components:
The outer capsule is made up of connective fibres, which actually cover the follicle.
The inner capsule contains many blood vessels, is an endocrine gland, and is able to secrete estrogen.
The seed cell membrane has 10 to 15 layers of granulosa cells.
The adult oocyte has reduced mitosis and has 22 stem chromosomes and an X sex chromosome.
Liquor folliculin contain estrogen in the follicle.
Over the effect of LH, the more rapidly the follicle ripens, protrudes out the peripheral part of the ovary and then ruptures, and the oocyte is released out. That is the oocyst phenomenon.
Also, under the effect of LH, the remainder of the ovary follicle gradually turns into the corpus luteum. At the end of the menstrual cycle, when LH falls in the bloodstream, the corpus luteum shrinks, leaving a white scar, called a white object or lymphoid.
Active e Separate endocrine
The granulosa cells and the follicle cells in the capsule secrete three main hormones: estrogen, progesterone and androgen. These hormones are sex hormones, with a sterane nucleus, so they are also called sex steroids.
Capsules in estrogen secretion.
The corpus luteum granulosa cells secrete progesterone.
Cells in the umbilical ovary secrete androgens (male hormones).
The oocyte can be considered as each unit of action of the ovary in terms of both reproductive and endocrine aspects. Indeed, a ripe follicle is capable of releasing a ripe oocyte for fertilization. The hormones of the oocyte and the corpus luteum are enough to alter the uterine lining to make the egg smooth, and if the woman is not conceived, it is enough to cause menstruation.
The effect of female sex hormones
It is called estrogen because strings are estrus substances for female mice that have had two ovaries removed. The ovaries secrete estrogen under the stimulation of LH in combination with FSH. Also, because the amount of FSH and LH changes cyclically, so does the amount of estrogen periodically change.
There are three main types of estrogen of the ovary: estradiol, estrogen and estriol. On the uterine lining, estradiol is 8 -10 times more potent than estrogen. Estriol has little effect on the uterine lining.
During the menstrual cycle, estrogen has two peaks, one on the eve of the ejaculate due to the maximum increase in secretion of the maturing follicle. It was found that this elevation of estrogen led to a peak of LH 1 day before oocyte release. This is because estrogen has increased the sensitivity of the pituitary to LH-KH of the hypothalamus, so the pituitary increases LH secretion rapidly.
The second peak of estrogen occurs about a week after the release of the ovule, at the time of luteal activity.
The specific effects of estrogen are as follows:
For uterine muscles:
Develops uterine muscle fibres, increases the size, length and number of muscle fibres. That makes the uterus enlarge.
Increases the sensitivity of the uterine muscle to oxytocin. Therefore, estrogen is considered to be the factor that easily causes miscarriage.
For the uterine lining
Mitochondrial stimulation, uterine mucosal proliferation, is considered to be a hormone that causes cancer of the uterine lining, the most obvious carcinogen of all known hormones.
Since the level of estrogen in the blood fluctuates periodically, the growth of the uterine lining also changes with the menstrual cycle, leading to growth, loss and periodic menstrual bleeding. If the progesterone’s community role was added, the menstrual course was even more pronounced.
For the cervix
Stimulates secretion of cervical mucus from the cervix, increases mucus, is clear and thin, creating favourable conditions for sperm to penetrate the upper genital tract of the woman.
In parallel with the increased secretion of mucus, the cervical opening is enlarged, allowing sperm to penetrate.
For the vagina
Develops vaginal epithelium, thickens vaginal walls through the effect of maintaining, slowing down cells of the vaginal epithelium. In people with inactive ovaries such as those in perennial menopause, who have had two ovaries removed, due to a severe lack of estrogen, the vagina will be atrophy thin, easy to bleed on impact.
Make the vaginal epithelium containing glycogen. Therefore, when using Lugol in the vagina, it will be dark brown because the iodine of Lugol acts on glycogen. Without estrogen, the vagina will not catch a dark brown, but only the pale-yellow colour of Lugol.
Comparing the vaginal environment due to the glycogen of the epithelium has been converted into lactic acid by the Doderlein bacillus in the vagina, making the pH of the vagina only 4.5 - 5.5. This is the active self-defence of the sound against the growth of pathogenic bacteria, in people with poor functioning of the ovaries, the anti-inflammatory ability of the vagina is also poor.
Enlarges large lips and small lips of the vulva. A person lacking estrogen, large lips, small lips will be underdeveloped and vulva will be parted. This is the case of young girls and old menopausal women.
Glands of the vulva such as Bartholin glands and Skene glands develop, stimulating these glands to secrete sebum.
Develops the milk glands of the breast and the stroma of the breast, causing the breast to expand. Combined with the effect of progesterone, fuller breast development.
Water retention, sodium retention, causing oedema.
Arousal requires sex.
Also, the vocal cords make the connection sound high
Help keep calcium in bones, contribute to good bone structure. People with severe estrogen deficiency and perennial menopause are susceptible to osteoporosis.
Progesterone is secreted by the corpus luteum in the second half of the menstrual cycle. However, the blood progesterone curve begins 1 day before oocyte release due to the early lysis of a matured follicle, under the effect of high concentrations of LH.
For uterine muscles:
Softens the uterine muscles. Reduces the sensitivity of the uterine muscles to oxytocin. Since then, the effect of keeping pregnancy and also known as the inert fetus.
Community with estrogen increases uterine muscle growth in both the number of muscle fibers, the length and the size of the muscle fibers. Therefore, during pregnancy, under the effect of high levels of estrogen and progesterone in the blood, the muscle from the uterus develops strongly, has a capacity to accommodate the rapidly growing fetus in the uterus.
For the uterine lining
Atrophy of the uterine lining. It is a unique hormone so far that is quite capable of treating cancer of the lining of the uterus. However, progestins (all substances with progesterone-like effects) are actually used to treat metastasis of these cancers in areas of the body where surgical treatments and Radiation does not resolve or is used to treat symptomatically for patients with endometrial cancer without surgery.
Community with estrogen and especially after it has been prepared with estrogen, making the uterine lining secretion. This secretion is closely related to the implantation of the uterine lining.
For the cervix
Antagonizes estrogen, inhibits the secretion of mucus of the glands in the cervical canal, reduces the amount of mucus, the mucus becomes cloudy and thick, the cervix closes, prevents sperm penetration. an upper genital tract of a woman. So, can be used as a contraceptive.
For the vagina:
Antagonistic against estrogen, premature removal of epithelial cells of the vagina, indirectly causes atrophy of the uterine lining, reduces the ability of the vagina to protect against inflammation. People using high doses of prolonged progestin, pregnant people are more prone to vaginitis than normal people.
For the breast:
Evolution of milk ducts.
It appears to have quite a bit of ability to reduce the growth of connective tissue of the breast and to treat fibroids in the early stage.
Community estrogen effect makes the breast develop comprehensively.
High-dose progesterone reduces mammary gland development.
The other uses:
Has a diuretic effect, reduces oedema?
The pregnanediol metabolite of progesterone increases body temperature from 0.3 ° c dcn to 0.5 ° c, with an average of 0.4 ° c. Applied in the diagnosis of oocyte based on bile in the period of increased temperature.
The reproductive cycle in women
On experimental rodents, it was found that the genital centre in the hypothalamus had two regions: the cyclic pre-active area and the non-cyclical post-activity area. In female animals, the front area is active and the back area is inactive. So, in female animals, sexual activity is cyclical. In male animals, the front area was inactive and the back area was active, so sexual activity did not have a cycle.
In women who are sexually active with a cyclic activity, many authors think that the cause of the woman's cyclic activity is the feed-back mechanism.
A woman's genital cycle with an average length of 28 days ranging from 22 to 35 days is considered normal. Each cycle begins with the start date of your period and ends with the start date of your next period. So, the genital cycle is also known as the menstrual cycle or the menstrual cycle.
At the beginning of each cycle, the Gn-RH of the hypothalamus stimulates the pituitary to secrete gonadotropin. The FSH of the pituitary gland stimulates the ovarian follicle to develop. In addition to the action of LH, this follicle secretes estrogen. When estrogen reaches a certain level, it affects the hypothalamus and pituitary gland to increase LH secretion, leading to oocyte release and luteum formation.
When the estrogen and progesterone of the luteum reach their peak, they inhibit the hypothalamus. Gn-kH-releasing hormone decreases. The pituitary gland stops secreting gonadal hormones. The corpus luteum shrinks, the hormones of the corpus luteum drop, causing the uterine lining to be removed, leading to menstruation.
As the sex hormones estrogen and progesterone decrease, the hypothalamus is no longer inhibited and Gn-RH starts again, opening a new cycle, a new menstrual cycle. This is a long exchange of exchange.
Regular menstruation is what proves the repentance mechanism is well done because the endocrine glands such as the pituitary and ovaries are all working. The secretion is good, although the hypothalamic and hypothalamus inhibitory hormone levels work well once they are not reversed. In other words, a woman who has menstrual periods is more likely to have the normal functioning of the hypothalamus-pituitary - ovary axis, that is, with the ovule, fertile.
Mechanical of menstruation
Menstruation is monthly periodic bleeding from the uterus due to rupture of the uterine lining under the influence of a sudden drop in estrogen and progesterone in the body.
If the menstrual cycle does not ovulate, only estrogen, the sudden drop of estrogen is enough to cause menstruation.
If the menstrual cycle is oocyte, luteal, then a sudden drop in both estrogen and progesterone is necessary to lead to menstruation.
Regarding the menstrual mechanism, the simple progesterone drop hypothesis has been rejected because progesterone alone does not expand the uterine lining and does not detach the uterine lining when it is dropped.
According to the work of Markee conducted in 1939 by grafting the uterine lining into the anterior chamber of the eye of the female gorilla, drawing the conclusion: estrogen evolved the spiral arterioles of the superficial layer of the uterus. When estrogen falls, these arterioles contract and end with extreme dilatation, leading to rupture of the vessel wall and menstrual bleeding.
According to the study of Shleeel, at the end of the menstrual cycle, under the effect of progesterone in combination with estrogen, appeared the sinus series (shunt) dynamic-vein. When estrogen and progesterone drop, the blood rushing from the arterioles into the venules ruptures the venous sinuses and causes menstrual bleeding.
Many authors point to necrosis and ablation of uterine mucosa to constricted blood vessels that cause anaemia.
All the above hypotheses are valid and phenomena occurring at the scope of the uterine lining are mixed, varied and at different degrees. Only one thing people still wonder about the mechanism of menstrual bleeding that is due to the result of a drop in female sex hormones. It is in the practice of estrogen therapy, sometimes bleeding also occurs. In this case, the estrogen does not decrease, but increases.
Properties of menstruation
The uterine lining is unevenly removed in different areas of the uterus, some places have flaky, some are flaking and some are not. That is why the period of dexterity is 3-5 days long. If the uterine lining is quickly and neatly removed, as is the case with curettage of the uterine lining, menstruation may only occur within a few hours.
It has been a long time ago that the uterine lining has been removed to regenerate immediately. It is not explained where the mechanism of this regeneration is, while sex hormones have not increased.
In non-oocyte menstrual cycles, the uterine lining is only affected by estrogen, there will be no dynamic-venous successive sinuses, but the only rupture of the helical arteries according to the mechanism of Markee, so menstrual blood is blood. bright red artery.
During the oviductal menstrual cycles, menstrual blood is usually dark in colour, tinged to brown. Is this blood flowing from the ruptured sinuses of the dynamic-venous junctions formed under the action of estrogen in combination with progesterone by Schlegel's mechanism?
Although it is called menstrual blood, it is not just blood but an unclogged suspension of blood containing mucus of the uterus, of the cervix, of the oviduct, fragments of the uterine lining, and detachable cells. of the vagina.
Haemorrhoids contain proteins, enzymes and prostaglandins. Usually, the blood clots in the vagina do not contain blood fibres, but only accumulate red blood cells in the mucus. Strong fibrinolysis and strong protein digestion occur in the uterine cavity and cervical mucus. The breakdown products of fibrinolytic and fibrinolytic are also very effective anticoagulants.
According to many authors, when the blood clot forms in the uterus, the blood fibres are immediately dissipated. Prostacyclin is rich in menstrual blood and also has an effect on blood vessels and antiplatelet effects. Therefore, during menstruation, the effect of fibrinolytic and proteolytic effects is constantly present, causing the waste materials through the menstrual blood to loosen and menstrual blood does not clot during menstruation.
Menstrual blood has a strong odour, not fishy like bleeding from other causes.
Menstrual cycles can vary from person to person, but little for the same person and during the age of sexual activity.
The amount of blood lost in each menstrual cycle varies with age, at 50 years of age, more menstrual bleeding than age 15. In general, people consider normal menstrual blood volume to be between 60- and 80-ml. Menstrual bleeding is usually high in the middle days of your period. There was no relationship between menstrual length and menstrual volume. The amount of menstrual bleeding can vary widely, up to 4 times between one person and another, but not much between periods.
- Characteristics General of menstruation
About the menstrual cycle, the period of menstruation (menstruation), the amount of menstrual blood, in addition to the influence of genital hormonal changes also depends on the condition and the talk of the quadrilateral mucosa. If the uterine lining has lesions such as inflammation, uterine fibroids, the regions do not respond evenly to the sex hormones, irregular growth and uneven shedding of the mucosa will occur, leading to menstruation. long and heavy bleeding.
In general, menstruation is a mirror that reflects the endocrine activity of the hypothalamus-pituitary - ovary axis and the condition of the uterine lining and is also a measure of the evolution of sexual activity. Of the woman.
Periods of a woman's sexual activity
In terms of sexual activity, a woman's life can be divided into three periods based on the development of menstruation
Period children (before puberty)
Lower levels of Gn-RH are limited in the hypothalamus. The pituitary also produces less gonadotropic hormones. but also release hormones, both gonadotropin hormones are gradually increased secretion, making the ovaries also gradually increase the secretion of estrogen. Progesterone is hardly secreted because the ovarian follicles are unripe, do not have an oocyte, and have no corpus luteum.
Gradually appear female genital signs such as slightly protruding breasts, pubic hair begins to grow sparsely as it approaches puberty.
The body also develops under a parallel action of growth hormones and sex hormones.
However, because the endocrine activity of the ovaries is not enough to significantly alter the uterine lining, it is not enough to lead to menstruation. The woman has not had a period.
When the hypothalamus is ripe, it is fully secreted with the Gn-RH releasing hormone to fully stimulate the pituitary to secrete gonadotropic hormones and finally the ovaries also fully secrete female sex hormones. Visceral mucosa leads to menstruation, young women menstruate for the first time and enter puberty.
In other words, sexual puberty is marked by your first period. Parallel to sexual puberty, there is a common puberty of the whole body.
The average age of puberty is around 13-16 years old. In some countries, puberty tends to be earlier, at 11-12 years old.
The signs of a woman's genitals appear clearly such as enlarged breasts, pubic hair develops, armpit hair begins to grow, and the vocal tone of the vocal cords becomes tighter. The underarm hair appears about two years after pubic hair.
Period of sexual activity
Next to puberty is the period of sexual activity, lasting until menopause. During this period, a woman often has regular periods, the rate of menstrual cycles with ovulation increases due to the hormonal activity of the hypothalamus-pituitary - ovary is completed. The woman can conceive.
During this period, the secondary sexual properties as well as the whole body of the woman continue to develop to the maximum. Period of sexual activity lasts 30-35 years.
Menopause is a woman's menopause. If it is said that a young woman who has not had her period due to her underactive hypothalamus activity, then a woman who stops menopause at menopause is because her ovaries are already depleted, too hypersensitive to the stimulus. gonadotropic hormones, so there is no longer enough secretion of sex hormones.
The average age of menopause is 45 - 50 years old. According to some baseline surveys, the average menopause age of Vietnamese is 47 ± 3 years old.
Since menopause, a woman is no longer quite likely to become pregnant.
People also divide the stages before menopause (perimenopause) and after menopause (postmenopausal). These phases usually last a year or two. But sometimes very long, up to ten years for the premenopausal period and sometimes very short, just a few months, even without clinical manifestations of perimenopause, but immediately transition to menopause.
In the premenopausal period, women who menstruate more easily to abnormal manifestations. The menstrual cycle can be long, it may also be short. The amount of menstrual bleeding may increase, it may also be less. If the cycle is short and the volume is high, the prognosis is likely that this stage will belong. If the menstrual cycle is long (thin menstruation) and the volume is low, then hope is true for menopause. The perimenopause cycles often fail to ovulate and a woman's fertility is significantly reduced.
The postmenopausal period is usually counted for two years. During this period, if the woman does not menstruate again, she can be considered to be completely menopause and the woman enters the period of old age, old age, and the end of her sexually active life (childbirth, child-rearing), to be more precise, terminates the lifespan of reproductive activities.