1.What is menstruation?
Menstruation refers to the periodic exfoliation and bleeding of the endometrium that accompanies the cyclical changes of the ovaries. In women with normal ovulation, at the end of an ovarian cycle, if the ovum is not fertilized, the corpus luteum degenerates, the level of estrogen and progesterone in the blood drops, and menstruation occurs. The age of menarche for girls is mostly between 13-15 years old.
2.What is a normal menstrual cycle?
The first day of bleeding is the beginning of the menstrual cycle, the interval between the first day of two menstrual periods is a menstrual cycle, regular for 28 days, but often shows irregularity, the normal cycle fluctuation range of 25-35 days; the duration of each menstruation is called the period, usually 2-8 days, the average of 4-6 days; the volume of menstruation is the total blood loss of a menstruation, the average of 20-60 ml. menstrual blood is dark red, in addition to blood In addition to blood, there are endometrial debris, inflammatory cells, cervical mucus and shed vaginal epithelial cells, etc.
In general, the length of the menstrual cycle depends mainly on the variation of the length of the follicular phase, and the length of the luteal phase of the cycle is relatively fixed, 95% between 10 and 16 days.
3. How many functional phases can the menstrual cycle be divided into?
The human menstrual cycle can be divided into four functional phases according to the structure and morphology of the ovaries and the production of steroid hormones.
1. Follicular phase: the first half of the menstrual cycle. Proliferative changes occur in the endometrium. After follicular recruitment is complete, a single follicle is selected from the follicular cluster (days 5-7) to become the dominant follicle (days 8-12) and eventually ovulation occurs (days 13-15). This process lasts for about 13 days and culminates in the formation of a preovulatory follicle, while all other follicles degenerate and atrophy.
2. Ovulation phase (follicle-luteal transition): After ovulation, the endometrium transforms from the proliferative phase to the secretory phase. the exact interval between the appearance of the LH wave and ovulation is about 35-44 hours after the wave initiation.
3. Luteal phase: The luteal phase is marked by a significant increase in progesterone secretion from the corpus luteum. Lysis of the corpus luteum occurs when there is no implantation of the embryonic follicle after ovulation.
4. Menstrual phase (luteal-follicular transition phase): initiation of the next cycle of follicular development depends on the degeneration of the corpus luteum in the preceding week, and the follicular recruitment of the next cycle is initiated by elevated FSH levels two days before the onset of menstruation.
4. What are the endometrial cyclic changes?
(1) Functional layer of the endometrium: 2/3 of the surface of the endometrium, which is influenced by ovarian secretion, is shed to form menstruation during menstruation.
Basal layer of the endometrium: the lower part of the functional layer, which is not affected by hormonal changes during the menstrual cycle and does not shed during menstruation. Regenerates and repairs the endometrial trauma after menstruation and re
formation of the functional endometrial layer.
(2) Histological changes of endometrium: Taking a normal menstrual cycle of 28 days as an example, the histological changes of endometrium are divided into.
1.Proliferative phase: the 5th-14th days of the menstrual cycle, the normal cycle usually lasts for 2 weeks and corresponds to the follicular phase of the ovarian cycle.
2. Secretory phase: 15th-28th day of the menstrual cycle.
3.Menstrual phase: the 1st-4th days of the menstrual cycle.
5.What are the physiological characteristics of each stage of a woman’s life?
(1) Fetal stage: It is the period from the fertilization of the egg to birth, which is 266 days on average.
After fertilization, a normal human embryo consists of 46, of which 22 autosomes originate from both parents. 46, XY embryos develop into males and 46, XX embryos develop into females. Y chromosomes determine the development of undifferentiated gonads into testes or ovaries. The sex chromosomes X and Y determine the sex of the fetus.
(2) Neonatal period: Infants within 4 weeks after birth. The female fetus is influenced by the maternal gonads and the sex hormones (mainly estrogen) produced by the placenta in utero, and its uterus, ovaries and breasts can develop to a certain extent, and some have the phenomenon of emulsion secretion. After birth, when separated from the maternal environment, the concentration of female hormones suddenly decreases, which may cause a small amount of vaginal bleeding, which is a physiological phenomenon and mostly disappears quickly.
Female fetuses are affected by female hormones produced by the placenta and maternal gonads in the mother’s body, and after birth, a fuller vulva can be seen, with slightly elevated breasts or a little lactation. After birth, when separated from the placental circulation, the level of female hormones decreases rapidly and a small amount of vaginal bleeding can occur.
(3) Childhood: from birth 4 weeks to about 12 years old, from the age of 8 years old, female characteristics gradually appear, after 10 years old slightly developed.
Before the age of 10, the child continues to grow and develop physically, but the genitalia are still infantile (small uterus, 1:2 ratio of uterine body to cervix). The uterus, fallopian tubes and ovaries are located in the abdominal cavity, near the entrance to the pelvis. From about 10 years of age, the follicles in the ovaries develop and secrete sex hormones under the influence of pituitary gonadotropins, but they still do not reach the mature stage. Female characteristics begin to appear, the uterus, fallopian tubes and ovaries gradually descend into the pelvic cavity, and breasts begin to develop.
(4) Puberty: The period from the first menstruation to the gradual development and maturity of the reproductive organs (WHO: 10-19 years old).
1. Breast eruption: the initial signs of female secondary sexual characteristics. Generally, girls’ breasts start to develop when they are close to 10 years old, and they develop into mature type after about 3-5 years.
2.First appearance of adrenal function: pubic hair and axillary hair appear.
3, growth acceleration: 11-12 years old adolescent girls physical growth is linear acceleration, the average annual growth of 9cm, the study of the first tide after the slow growth.
4, the onset of menstruation: estrogen levels reach a certain height and decline, causing uterine withdrawal bleeding that is the first menstruation, generally 11-12 years old. The first menstruation is on average 2.5 years later than breast development. It is an important sign of the beginning of puberty. It lacks regularity because the ovaries are not yet functioning properly. After the menarche, menstruation usually takes a few months, half a year or more before it becomes regular, and after 5-7 years of establishing a regular cycle of ovulation, menstruation gradually becomes normal. If a girl does not see menstruation at the age of 18, the reason should be identified.
5.Change of hormone level during puberty: At the beginning, there is no LH peak formation, and there is no ovulation. Later, the estrogen level rises, together with the rise of FSH level, there is LH peak formation and ovulation.
(5) Sexual maturity: the period when the ovaries mature and secrete sex hormones and ovulate periodically.
It generally starts to mature at the age of 18 and lasts for about 30 years. This is the period when women’s fertility is at its peak, also known as the fertility period.
(6) Menopausal transition: It used to be called menopause, but now it is called perimenopause. Ovarian function gradually decline, the reproductive organs began to atrophy to decline change. The menstrual flow is low and finally menopause starts at the age of 40 and lasts for 10-20 years. 1994, WHO proposed.
Including the period before and after menopause, it is also divided into.
1, pre-menopause: a decrease in the number of follicles, irregular menstruation, and generally no ovulation.
2, Menopause: natural menopause is usually the last menstruation in a woman’s life, with natural depletion of follicles in the ovaries or loss of response to pituitary gonadotropins in the remaining follicles. Age: average 49.5 years, 80% between 44-54.
3. Late menopause: further atrophy of the ovaries, endocrine function fades, and atrophy of the reproductive organs.
(7) Old age: Generally after 60 years old, ovarian function has completely disappeared, the whole body tissues are atrophied and aging, the vagina is obviously eh, even with senile vaginitis, difficulty in sexual intercourse, urinary tract infection, urinary incontinence, etc. Vaginal atresia occurs in severe cases. Osteoporosis and coronary heart disease increase significantly in older women, and prevention should be actively started from menopause.