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Section 1 Anatomy and Physiology of Female Reproductive System

I. external genitalia and internal genitalia

(1) external genitalia

Female external genitalia, also known as vulva, refers to two internal areas from pubic symphysis to perineum, including * * *, size * * *, * * *, vestibule, urethral orifice, * * mouth, hymen, vestibular gland and perineum.

1.* * * is a fat pad in the pubic symphysis, which begins to grow on the skin in adolescence and is distributed in a triangle with the tip down.

2.Da * * * is a pair of skin folds near the inner side of the two strands, with the front connected to * * * and the back connected to the perineum. Unmarried women's bilateral large * * naturally closed, covering the * * * mouth and urethral orifice. Postpartum uterus is separated from both sides and atrophies after menopause.

3. Small * * * is a pair of thin folds located on the inside of big * * *, with moist surface and reddish inside, and rich nerve endings in the skin, so it feels keen. The front ends of the small * * on both sides merge with each other and are divided into two leaves, which are wound around the * * * respectively. The front leaves form the foreskin of the * * *, and the back leaves form the * * * lacing. The rear end of the small * * * is connected with the rear end of the big * * *, forming a transverse fold at the midline, which is called a * * * lace.

4.* * * is located at the top between the small * * * on both sides, similar to the spongy tissue of male * * *. * * * The head is rich in nerve endings, extremely sensitive and erect.

5.* * * The vestibule refers to the diamond-shaped area between small * * * on both sides, with * * * as the front boundary, small * * * on both sides as the inside and * * * as the back boundary. In this area, there is a urethral opening in front and a mouth in the back.

6. Vestibular glands, also known as papillary glands, are located behind the big * * * (such as soybeans), one on the left and one on the right. The glandular duct opens in the groove between the small mouth of * * * and the hymen, and secretes mucus during sexual excitement to make * * * smooth.

7. The urethral orifice is located between the mouth of * * * and the mouth of * * *, which is an oval opening of urethra. There are two paraurethral gland openings at the posterior urethral wall near the external orifice, which is a place where bacteria are easy to lurk.

8.* * * Mouth and hymen * * * Mouth are located below the urethral orifice and behind the vestibule, and their shapes and sizes are often irregular.

* * * The mouth is covered with a membrane called hymen. There is a small hole in the center of the membrane. The shape and size of the hole and the thickness of the membrane vary from person to person. The hymen is often broken for the first time, and it is further damaged during childbirth, leaving a few small raised hymen marks after childbirth.

9. The perineum refers to the soft tissue between the posterior commissure of * * * and * * *, and it is also a part of the pelvic floor.

(2) Internal genitalia

Female internal genitalia include * * *, uterus, fallopian tube and ovary, the latter two are often called uterine appendages.

1.* * * is located between uterus and vulva, which is the organ of * * * and also the channel for menstrual blood outflow and fetal delivery. The upper end surrounds the cervix, and the lower end is in the vestibular opening. * * * The upper part around the cervix is called * * * vault, which is wider than the lower part of * * * and is divided into four parts: front, back, left and right. So * * * The back wall length is 10- 12 cm, and the front wall length is 7-9 cm. Between the anterior wall and bladder and urethra, it is called bladder septum, between the posterior wall and rectum, it is called rectal septum, and between the upper segment of the posterior wall and rectum, it is the lowest part of abdominal cavity, which is called hysterorectal recess, which has important clinical significance.

2. The uterus

(1) The functional uterus is a hollow organ, and the cavity is covered with mucosa, which is called endometrium.

From adolescence to menopause, the endometrium is affected by ovarian hormones and changes periodically, resulting in menstruation; After * * *, the uterus is the channel for * * * to reach the fallopian tube; After conception, the uterus is the place where the fetus is conceived; During childbirth, the fetus and its accessories are delivered through uterine contraction.

(2) The dissected uterus is in the shape of an inverted pear, with small wall thickness, wide and free upper end and narrow lower end. The uterus of an adult woman is about 7-8 cm long, 4-5 cm wide and 2-3 cm thick. The wider part of the upper part of the uterus is called the uterine body, and the protruding part of its upper end is called the uterine bottom. The uterine horns on both sides of the bottom of the uterus communicate with the fallopian tubes. The smaller part of the lower part of the uterus is called the cervix, which is cylindrical and part of it extends into * * *. The opening that connects people with * * * is called the external cervix. The parturient is round and damaged during delivery, and the parturient turns into transverse fissure, and the cervical tissue is divided into upper and lower or front and rear lips. The ratio of uterine body to cervix is 2: 1 for adults and 1: 2 for infants.

The uterine cavity is divided into two parts: the body cavity and the cervical canal. The uterine cavity is a triangle with a wide top and a narrow bottom. Both sides of the upper part pass through the fallopian tube and enter the abdominal cavity, and the lower part communicates with the cervical canal. The narrowest part is called the isthmus of uterus. The upper end of isthmus is anatomically narrow, which is called anatomical internal orifice, and the lower end of isthmus, because the mucosal tissue here changes from endometrium to cervical endometrium, which is also called internal orifice of tissue. The cervical canal is spindle-shaped, and the cervix enters * * *, with the vault as the boundary, which is divided into the upper part of the cervix and the cervix.

(3) Tissue structure The uterine body wall is very thick and consists of three layers of tissues, the outer layer is serosa (i.e. visceral peritoneum), the middle layer is muscularis, and the inner layer is mucosa (i.e. endometrium).

Endometrium is a soft, smooth, fluffy and pink mucosal tissue, which is divided into basal layer and functional layer. The functional layer changes greatly in the middle period of menstruation and pregnancy.

The myometrium is the thickest layer of the uterine wall and consists of smooth muscle bundles and elastic fibers. Muscle bundles are staggered, the outer layer is vertical, the inner layer is round, and the middle layer is intertwined in many ways.

The uterine serosa layer covers the bottom of the uterine body and the anterior and posterior peritoneum, and is close to the muscular layer. Near the isthmus in front of the uterus, the peritoneum is loosely combined with the uterine wall, so that the peritoneum folds forward and covers the bladder, forming a bladder uterus depression; Behind the uterus, the peritoneum descends along the uterine wall, covering the back of the cervix and the posterior fornix, and then folding to the rectum, forming a uterorectal recess.

The cervix is mainly composed of connective tissue, including smooth muscle and elastic fibers. There are many glands in the mucous membrane of the cervical canal, which can secrete mucus and be alkaline, forming a mucus plug of the cervical canal. The surface of cervix is covered with squamous epithelium.

④ Uterine ligament

The round ligament starts from the front of both sides of the uterine horn and below the proximal end of the fallopian tube, and then extends forward and downward along the broad ligament to the pelvic walls on both sides, stopping at the groin, which has the function of keeping the uterus in a forward leaning posture.

Broad ligament is a pair of wing-like peritoneal folds, which starts from both sides of the uterus and extends outward to the pelvic wall, dividing the pelvic cavity into two parts. The upper edge of the ligament is free, the inner 2/3 of which surrounds the fallopian tube (the umbrella-shaped end is not covered by peritoneum), and the outer 1/3 extends from the umbrella-shaped end of the fallopian tube to the pelvic side wall, which is called pelvic infundibular ligament, which has the function of supporting the ovary, so it is also called ovarian suspensory ligament, through which ovarian blood vessels pass.

The uterosacral ligament extends from the upper side of the cervical internal opening behind the cervix to both sides, bypasses the rectum, and ends at the anterior fascia of the second and third sacrum, and is used for pulling the cervix backwards and upwards to keep the uterus in a forward leaning position.

The main ligament, also known as the transverse cervical ligament, is located at the base of the broad ligament on both sides of the uterus and reaches the pelvic wall from the side of the upper part of the cervix, which is the main force to fix the position of the cervix. Arteriovenous and ureter of uterus reach the terminal organ through the upper edge of main ligament.

3. The fallopian tube is a slender and curved tube, the inner side of which is connected with the uterine horn, and the outer end is free, which is funnel-shaped and about 8- 14cm long.

4. The ovary is a female gonad, one left and one right, which is gray flat ellipsoid. Before puberty, the surface of the ovary is smooth, and after ovulation, the surface is gradually uneven. The size of the ovaries of adult women is about 4cmX3cmXlcm, and the ovaries gradually shrink after menopause.

The ovary is located below the fallopian tube, and the part from the mesoovary to the posterior lobe of the broad ligament is the ovarian portal, and the ovarian blood vessels pass through the mesoovary and pass through the ovarian portal.

Ovary is divided into cortex and medulla. The cortex is located in the outer layer, which contains many primitive follicles and developing follicles. Medulla is located in the center of ovary and contains blood vessels, lymphatic vessels and nerves.

Second, pelvis and pelvic floor.

(1) pelvis

The female pelvis is an important part of the birth canal. Because it is bony tissue, it is called bone birth canal. The size and shape of the pelvis are closely related to the smooth delivery, so we should have a clear understanding of the structure and characteristics of the pelvis.

1. The structure of pelvis is composed of sacrum, coccyx and two hip bones, each of which is composed of ilium, ischium and pubis. The sacrum is composed of five sacrums, the inner surface of which is concave, and 1 sacrum protrudes forward to form a sacral promontory, which is an important symbol of pelvic measurement. The coccyx is composed of 4-5 coccygeal vertebrae, and its upper edge is connected with sacrum to form sacrococcygeal joint, which has a certain mobility. The anterior part of the hip bone is between two pubic bones and connected by fibrocartilage, which is called pubic symphysis. The two descending branches of the pubic bone form the pubic arch with an average angle of 90~ 100℃. Behind the pelvis, the sacrum is connected with the bilateral ilia, forming a sacroiliac joint, which is very tough. In addition, there are two strong ligaments emanating from the dorsal surface of the sacrum, which stop at the ischial tubercle and the ischial spine respectively, and are called the sacral tubercle ligament and the sacrospinous ligament. Affected by hormones during pregnancy, ligaments are slightly relaxed; Each joint has a certain degree of ductility, which is conducive to childbirth.

When the superior margin of pubic symphysis is connected with the superior margin of sacrum through iliopubic line, the pelvis can be divided into two parts: the upper part is a false pelvis and the lower part is a true pelvis. The former has little to do with delivery, and the latter is the only way for fetal delivery, so its size and shape are closely related to delivery, but it is difficult to measure it directly in clinic. Generally speaking, the size of true pelvis can be estimated indirectly by measuring the diameter of false pelvis.

2. Female pelvis is characterized by shallow and wide, cylindrical, larger entrance and exit than male pelvis, short and wide pubic symphysis, large angle of pubic arch, small sacrum promontory, short and wide sacrum, small curvature and wide ischium.

3. Pelvic plane In order to understand the process of the fetus passing through the pelvic cavity (bone birth canal) during childbirth, the pelvis can be divided into four main imaginary planes.

(1) The population plane (pelvic population) is the intersection of the true pelvis and the false pelvis, which is approximately circular or transverse oval in shape, and has four radial lines: ① the anterior and posterior diameter of the entrance, also known as the true union diameter, and the average length of the line connecting the upper edge of pubic symphysis to the upper edge of sacrum is 1 1cm. ② The transverse diameter of the population is the largest median diameter of bilateral iliopubic line, with an average of 13.5cm③ The oblique diameter of the entrance, one on the left and one on the right. The left oblique diameter is the line from the left sacroiliac joint to the right iliac crest, and the right oblique diameter is the line from the right sacroiliac joint to the left iliac crest, with an average value of 12.75cm.

(2) The widest plane of pelvis is the widest plane of pelvis, the anterior boundary is the posterior midpoint of pubic symphysis, and the posterior boundary is between the second and third sacral vertebrae. Both sides are equivalent to the center of acetabulum, and the length of its anterior-posterior diameter and transverse diameter is about 12: 5 cm.

(3) The pelvic median plane is the narrowest plane in the pelvic cavity, with the anterior boundary being the lower edge of pubic symphysis, the posterior boundary being between the 4th and 5th sacral vertebrae, and the sciatic spines on both sides, with the anteroposterior diameter of about110cm and the transverse diameter of about10 cm. The connection line between the bilateral ischial spines is an important sign to understand the descent of fetal head during labor.

(4) The exit plane actually consists of two triangular planes. The apex of the anterior triangle is the lower edge of the pubic symphysis, and the edge is the descending branch of the pubic bone on both sides; The top of the posterior triangle is the sacrococcygeal joint, and the lateral part is the ligament of the sacral tubercle. The diameter between ischial tubercles is the same as the bottom, and it is also the transverse diameter of pelvic outlet, with an average of 9cm. The diameter between ischial tubercles is longer and the angle of pubic arch is larger. The anteroposterior diameter of pelvic outlet is the distance from the lower edge of pubic symphysis to sacrococcygeal joint, with an average of 1 1.5 cm. The straight line from the lower edge of pubic symphysis to the midpoint of the diameter between ischial tubercles is called the anterior sagittal diameter of pelvic outlet, which is about 6cm long. The line from sacrococcygeal joint to the midpoint of ischial tubercle is called posterior sagittal diameter, which is about 9em long. Posterior sagittal diameter is very important in obstetric clinic.

4. Pelvic axis, also known as delivery axis, is an imaginary axis connecting the central point of pelvic plane. Its upper section is downward and backward, its middle section is downward, and its lower section is forward and downward. During delivery, the fetus is delivered along this axis.

(2) pelvic floor

Pelvic floor is composed of muscles and fascia, which closes the pelvic outlet and penetrates through urethra and rectum, and has the function of supporting pelvic organs and keeping them in normal position. If the pelvic floor tissue is damaged during delivery, the pelvic floor will relax and affect the position of pelvic organs, and uterine prolapse may occur.

The pubic symphysis is in front of the pelvic floor, the coccyx is in the back, and the descending pubic branch, the superior sciatic branch and the ischial tubercle are on both sides. The pelvic floor is divided into three layers from outside to inside: superficial fascia and muscle, urogenital septum and pelvic septum.

Third, the periodic changes of ovary and its hormones.

(a) follicular development and maturation

There are about 654.38+ 10,000-500,000 egg cells in the ovary when the newborn is born. Each oocyte is surrounded by a layer of primordial follicular cells, also called granulosa cells, and the basement membrane is also surrounded by them to form primordial follicles.

Due to the effect of follicle-stimulating hormone in the anterior pituitary gland, primordial follicles began to develop, but more than 99% of primordial follicles degenerated and atrophied into atresia follicles at different stages after development. Generally only one follicle matures and ovulates every month. In a woman's life, about 400-500 eggs can mature and ovulate. After puberty, the oocytes in some primordial follicles increase, the surrounding granular cells proliferate into multiple layers, and the FSH receptors on the cell surface increase, forming a transparent membrane around the oocytes, called zona pellucida. The granular cells outside the zona pellucida are arranged radially, which is called radiation crown. At the same time, under the action of FSH, interstitial cells around follicular development and mature follicles differentiate into the inner and outer layers of theca cells. Follicle cells secrete androgen, which is converted into estrogen by aromatase activated in granulosa cells. The synergistic effect of estrogen and FSH makes luteinizing hormone (LH) receptor synthesized on theca cells and granulosa cell membranes. These hormones, exudates from blood circulation and other protein gather in the interstices of granulosa cells, which is called follicular fluid. Follicle fluid gradually increases, the gap increases, and oocytes and proliferating granular cell layers protrude into the cavity to form cumulus. At this time, the follicle matures and moves to the surface of the ovary, showing transparent vesicles, which are called mature follicles. B-ultrasound showed that the diameter of mature follicles was about 18-25mm.

(2) Ovulation

The mature follicle is affected by luteinizing hormone (LH) in the anterior pituitary gland, the theca dissolves and ruptures, the follicular fluid flows out, and the mature oocyte and its surrounding cumulus are squeezed out of the abdominal cavity. This process is called ovulation. The mechanism of ovulation has not been fully clarified. Recently, some people think that ovulation may be related to the contraction of smooth muscle fibers around mature follicles caused by prostaglandin. Ovulation usually occurs in the middle of the 28-day menstrual cycle, or about 14 days before the next menstruation. Two ovaries ovulate alternately, or one ovary ovulates continuously.

(3) Formation and atrophy of corpus luteum

After ovulation, the follicular wall collapses, and the blood vessels in the vesicle rupture and bleed, and condense into blood clots in the vesicle, which is called blood clots. After that, the breach of follicular wall was quickly closed and repaired by fibrin, and blood was absorbed to form corpus luteum. Granular cells remaining in follicles accumulate yellow lipid-like particles to form luteal cells. 7-8 days after ovulation, the corpus luteum reached its peak, with a diameter of about 1-3cm, yellow in color and protruding from the surface of the ovary.

If the egg is fertilized, the corpus luteum will continue to develop into pregnant corpus luteum, and its function will be replaced by placenta after pregnancy 10. If the ovum is unfertilized, the corpus luteum begins to shrink on the 9th ~10 day after ovulation (i.e. the 24th ~ 25th day of menstrual cycle), the yellow color turns pale, the cell degenerates, and the secretion of sex hormones also decreases. Until the 28th day of the cycle, the endometrium can't be maintained and falls off, leading to menstrual cramps.

The atrophic corpus luteum lasted for 8- 10 weeks, and finally became a fibrotic white body with a scar shape.

(4) Hormones secreted by ovary

Ovary mainly synthesizes and secretes two kinds of estrogen, namely estrogen and progesterone, and also secretes a small amount of androgen.

1. Estrogen is mainly secreted by follicular endometrial cells and granulosa cells. In the early stage of follicular development, estrogen secretion is less. With the development and maturity of follicles, the secretion gradually increased, reaching a peak 24 hours before ovulation, and the secretion of estradiol reached 400mg, and then decreased slightly. During the development of corpus luteum, the secretion gradually increased and reached the second peak when corpus luteum matured. After that, it gradually decreased, and it dropped sharply to the lowest before menstruation. Its main physiological functions are:

(1) can promote follicular development. If it is insufficient, it will lead to follicular development stop and atresia.

(2) It can promote uterine development, endometrial hyperplasia and myometrial thickening; It can increase the sensitivity and contractility of uterine smooth muscle to oxytocin; It can increase the secretion of mucus in the cervical canal, make it thinner and easy to be drawn into filaments, which is beneficial to the passage of mucus.

(3) It can promote the development of fallopian tubes, strengthen the rhythmic contraction of fallopian tubes, and facilitate the transport of pregnant eggs.

(4) make * * * epithelial cells proliferate and keratinize, increase intracellular glycogen, and keep * * * weak acidity.

(5) Promote vessel element proliferation of mammary gland, make areola colored, accumulate tissue fat, and inhibit milk secretion by inhibiting prolactin secretion.

(6) The feedback regulation of hypothalamus and pituitary gland has both inhibitory negative feedback and promoting positive feedback, that is, inhibiting the secretion of pituitary follicle-stimulating hormone and promoting the production of pituitary luteinizing hormone, thus indirectly regulating ovarian function.

(7) Promote the retention of water and sodium.

(8) Promote the deposition of calcium in bones and accelerate the epiphyseal closure.

2. Progesterone is the intermediate of androgen and estrogen synthesis, so progesterone exists in ovary, testis, adrenal cortex and placenta, and is mainly secreted by luteal cells and follicular cells after ovulation. At the early stage of follicular phase, the content of progesterone in blood is very small. Before ovulation, the content of progesterone in the blood increased slightly because the follicle began to luteinize. After ovulation, with the development of corpus luteum, the secretion of progesterone increased significantly, reaching a peak at the maturity of corpus luteum 7-8 days after ovulation, reaching 30mg every 24 hours, and then gradually decreasing, and then dropping sharply in the second half of corpus luteum, reaching the lowest level before menstrual cramps. Its main physiological functions are:

(1) changes the endometrium from proliferative phase to secretory phase, reduces the excitability of uterine muscles, and is beneficial to the implantation of pregnant eggs and embryo development.

(2) inhibit the secretion of mucus in the cervix and endometrium, and make it sticky.

(3) Inhibition of oviduct peristalsis.

(4) make * * * epithelial cells fall off, glycogen deposition and * * * lactobacillus decrease, and the acidity decreases.

(5) Promote the development of mammary glands, and high-dose progesterone can inhibit milk secretion.

(6) It can slightly increase the body temperature of normal women, and the basal body temperature can be increased by 0.3℃-0.5℃ after ovulation.

(7) There is only inhibitory negative feedback on hypothalamus and pituitary, thus inhibiting the release of luteinizing hormone and follicle stimulating hormone in the anterior pituitary.

3. Androgen in women mainly comes from adrenal cortex, and the outer theca cells and ovarian interstitial cells can produce a very small amount of androgen. Androgen can promote axillary hair growth, protein synthesis, muscle growth and bone development, and erythropoiesis. A large number of androgens have antagonistic effects on estrogen.

Fourth, the reproductive organs and menstrual cycle changes.

Estrogen and progesterone, two main hormones produced in the process of ovarian periodic changes, affect the changes of reproductive system, most obviously the periodic changes of endometrium, which leads to menstruation. In addition, the cervix, fallopian tubes and epithelial cells also undergo corresponding periodic changes.

(a) Periodic changes of endometrium

Generally, it is divided into four periods, but it is actually a continuous development process.

1. The 5th-14th day of the menstrual cycle in proliferative phase is equivalent to the mature period of follicular development, and the significant hyperplasia of endometrium is the main feature of this period. Under the action of estrogen secreted by newborn follicles, the endometrium after menstruation is regenerated and repaired by basal cells, and then proliferates rapidly, and the glands in the endometrium increase. At the end of proliferation, the thickness of glandular duct changed from straight tube to spiral, glandular epithelial cells changed from cubic to high column, the nucleus gradually moved from bottom to center, and empty robe appeared under the nucleus. Interstitial hyperplasia is dense, cells are stellate, and arterioles are elongated and spiral.

2. The first15-24th day of menstrual cycle in secretory phase is equivalent to luteal phase. The corpus luteum secretes a large amount of progesterone and estrogen, which acts on the hyperplastic endometrium, making it continue to thicken and the glands are highly secreted, which is the main histological feature of this period. At this time, the glandular duct is further enlarged and bent, the section is serrated, and the glandular cavity contains a lot of mucus. The glandular epithelial cells are enlarged, the nuclei move to the bottom, there are many secretory granules in the cytoplasm, interstitial cells are edematous, the cytoplasm of interstitial cells is enlarged, and arterioles grow rapidly, spiral and obviously curved. In the late secretory stage, the intima can be thickened by 5-6n, which is obviously divided into three layers. ① Basal layer: Close to the myometrium of uterus, with no obvious change in menstrual cycle. The repair of endometrium after menstruation begins from this layer. ② Sponge layer: Located at the basal layer, it is the thickest layer of intima and contains hyperplastic glands and blood vessels. Its cross section is loose and spongy, with periodic changes and shedding during menstruation. ③ Dense layer: On the surface of endometrium, glands are small and have periodic changes, so it is called functional layer when laminated with sponge.

3. Premenstrual period, that is, the 25th to 28th day of menstrual cycle, is equivalent to luteal degeneration. If you are not pregnant, due to the rapid decline of estrogen and progesterone in the blood, endometrial degeneration, interstitial edema gradually disappears, tissues become dense, glandular ducts are compressed, and spiral arterioles in the endometrium are squeezed and curled, and blood flow slows down. 4 ~ 24 hours before menstruation, the spiral arteriole appears local spasmodic contraction, which leads to ischemia, hypoxia and necrosis of endometrial functional layer. When blood vessels contract for a certain period of time and relax, the terminal blood vessels are damaged and ruptured due to lack of oxygen, and blood overflows, forming a small subcutaneous hematoma.

4. Menstruation is on the first 1-4 day of the menstrual cycle, that is, the menstrual period. The main characteristics of the endometrium are bleeding and shedding. Due to the rupture of blood vessels, the outflow of blood forms many small hematomas at the bottom of sponge layer. With the decomposition of enzymes, the intima gradually falls off from the basal layer in pieces or dispersedly, and is discharged after mixing with blood, which is menstruation. When the hematocele in the uterine cavity reaches a certain amount, it excites the inner wall of the uterus, causing reflex cervical relaxation and uterine emptying contraction, so normal menstrual blood is intermittently discharged. Finally, the whole functional layer almost fell off, and there were glandular tubes and blood vessels on the surface of the intima, without epithelial coverage.

Then the intimal wound began to repair from the basal layer, and new epithelium grew from the broken end of the glandular duct to cover the intimal surface. New blood vessels grow from the broken end of the blood vessel. The new blood vessels are vertical to the intima surface, thin and long. But at this time, the intima is extremely thin, with a thickness of about 1-2mm, with small glands, straight glandular ducts and square cells at the base. So the menstrual period is actually the end of the previous cycle and the beginning of a new cycle.

(2) Periodic changes in other parts of the genitals

1. Periodic changes of fallopian tubes During the follicular phase, the epithelial cells of fallopian tubes were affected by estrogen, the ciliated cells widened, the nuclei were near the surface, the nuclei of ciliated cells were near the base, and there were no secretory granules in the cells. In luteal phase, ciliated cells become shorter under the action of progesterone, while ciliated cells protrude from the surface and contain a lot of glycogen, which is beneficial for pregnant eggs to absorb nutrients during tubal surgery.

2. Periodic changes of cervix and its secretions. The periodic changes of cervical mucosa are not obvious, but the mucus secreted by its glandular cells changes periodically. After menstruation is clean, the level of estrogen in the body is low and the secretion of cervical mucus is less. With the continuous improvement of estrogen level, cervical mucus secretion gradually increases and becomes thin and transparent, like egg white. During ovulation, secretion reaches its peak, and mucus can be elongated into filaments. After the mucus is coated on the glass slide and dried, fern leaf crystals can be seen under the microscope, which can appear in the 6-7 days of menstrual cycle, and the crystal shape before ovulation is the most typical. After ovulation, under the action of progesterone, mucus becomes sticky and turbid, with poor ductility and easy to break when drawing. After the smear is dried, the phyllodes of ferns disappear and are replaced by ellipsoids arranged in strips.

3. Periodic changes of * * * cells Before ovulation, under the action of estrogen, the bottom cells of * * * epithelium proliferate and gradually evolve into middle and surface cells. The degree of keratinization of surface cells increases, and the content of glycogen in cells increases, which is decomposed into lactic acid by * * * bacteria parasitic in * * *, so that it keeps a certain acidity in * * *, thus inhibiting the reproduction of pathogenic bacteria, which is called * *. After ovulation, the epithelial cells of * * * are accelerated to shed under the action of progesterone, and most of the shed cells are mesothelial cells or pre-keratinized cells. Clinically, ovarian function is often understood according to the changes of exfoliated cells.

Verb (abbreviation of verb) regulation of sexual cycle

After sexual maturity, due to the periodic changes of ovaries, reproductive organs also have corresponding periodic changes, which is called sexual cycle. Ovary secretes sex hormones and can act on its target organs, which are mainly regulated by hypothalamus and pituitary gland. It is called hypothalamus-pituitary-ovary axis and is controlled by the central nervous system. Menstruation is only an important sign of sexual cycle, and whether it is normal or not can reflect the regulatory function of the whole nerve-endocrine system.

(A) Hypothalamic regulation of pituitary gland

It has been proved that some neurons in hypothalamus have endocrine function and produce gonadotropin-releasing hormone (CnRH). GnRH is a decapeptide hormone with high biological activity. It reaches and acts on the anterior pituitary through the portal vein circulation, regulating the synthesis and release of two pituitary hormones, namely follicle stimulating hormone (FSH) and luteinizing hormone (LH), so that the two pituitary gonadotropins leave the cells and enter the blood circulation. The gonadotropin-releasing hormone in hypothalamus is secreted in pulses, and it is secreted every 60- 120 minutes on average. The amplitude and frequency of pulse are higher in follicular phase, but lower in luteal phase. There are sex hormone receptors in hypothalamic neurons.

(2) The pituitary gland regulates the ovary.

Two gonadotropins (FSH and LH) produced by pituitary gland under the action of GnRH are glycoprotein hormones, which can directly affect the ovarian cycle. There are FSH receptors on ovarian granulosa cells and interstitial cell membranes. Under the action of FSH, aromatase in granulosa cells is activated, and interstitial cells near follicles differentiate into the inner and outer layers of theca cells. At the same time, the synergistic effect of FSH and estrogen enables LH receptors to be synthesized on granulosa cells and follicular membranes.

Therefore, in the follicular phase, FSH can make the oocytes enlarge, the follicles mature, and the endometrial cells and granulosa cells produce estrogen. The first peak of estrogen level appeared 24 hours before ovulation.

During ovulation, FSH and LH cooperate, especially the peak of LH release, which leads to ovulation in mature follicular rupture.

In luteal phase, LH mainly acts on luteal cells (granulosa cells luteinizing) to produce progesterone, which reaches its peak 7-8 days after ovulation. At the same time, FSH acted on follicular cells to continue to produce estrogen, and the second estrogen peak appeared at the same time as progesterone.

FSH and LH in the pituitary gland are also secreted in the form of pulses. There are GnRH and estradiol receptors in pituitary gonadotropin secreting cells.

(C) the feedback effect of ovarian hormones

Sex hormones secreted by ovaries adversely affect the production and release of endocrine hormones in hypothalamus and pituitary gland, which is the so-called feedback effect of ovarian hormones. If it is promoted, it is called positive feedback; if it is inhibited, it is called negative feedback. Sex hormones have feedback effect because there are corresponding receptors on the functional cells of hypothalamus and pituitary.

Estrogen is mainly estradiol (E2), which has positive feedback and negative feedback, but its positive feedback is conditional. Estrogen increases the release pulses of GnP, H and H in hypothalamus and inhibits the release pulses of FSH in pituitary gland. Therefore, at the end of follicular phase, estrogen level is higher and LH frequency increases. At the first peak of 24 hours before ovulation, estrogen not only increased the GnRH release pulse of hypothalamus, but also made the norepinephrine function of hypothalamus have an exciting positive feedback effect when E2 secretion reached 734nmoVml, which led to the peak change of LH blood concentration and induced ovulation. It must be clear that GnRH secreted by hypothalamus mainly regulates the synthesis and release of pituitary LH. When GnRH pulse

When the amplitude and frequency of flushing increase, LH secretion increases; When the amplitude and frequency of GnRH pulse secretion decrease, it is beneficial to FSH secretion.

Progesterone (P) decreased the GnRH release pulse in hypothalamus and had no obvious feedback effect on pituitary gland. Progesterone can inhibit the positive feedback of estrogen, while the synergistic effect of progesterone and estrogen produces strong negative feedback. Therefore, when the second peak of estrogen appears in luteal phase, it is impossible for the peak of LH to change because of the presence of progesterone at the same time.

To sum up, under the control of the cerebral cortex, the pituitary-ovarian axis of subthalamic bacteria maintains the dynamic balance of endocrine through adjustment and feedback, so that the ovaries change periodically, and the reproductive organs of women of childbearing age also change periodically.

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