Physiology Urogenital System Genital L 5 Uterine cycle

Physiology Urogenital System Genital L 5 Uterine cycle

• Uterine cycle Endometrial cycle Menstrual cycle It is the cyclic changes of the endometrial tissues It depends on ovarian cycle.

Structure of the endometrium: Functional layer: It is supplied by the spiral arteries. It is the superficial layer of endometrium. It is shed out with menstrual B. monthly. It is replaced by new layers from the basal layer. Basal layer: It is supplied by the basal arteries. It is not changed with the menstrual cycle It is responsible for regeneration of the functional layer after shedding out.

Phases of menstrual cycle 1. The proliferative phase: 2. The secretary phase: 3. The destructive phase:

1. The proliferative phase: The pre-ovulatory The follicular or The estrogen phase. Started after menstrual flow and end at ovulation. Coincides with the follicular phase of the ovary. Its duration is about 9 days, but may vary with the variation in the duration of: a. The menstrual flow [3 -5 days] b. The time of ovulation [14 th - 17 th day]

Hormonal control of the proliferative phase The estrogen secreted from the Graafian follicle. will produce: 1. Increase in thickness of endometrium up to 2 – 3 mm due to the rapid proliferation of its stromal & epithelial cells. 2. Increase in the length of the uterine glands but there is no secretion.

2. Post-proliferative phase The secretary phase, the Luteal phase, the progesterone phase, and the premenstrual phase. Started at the 14 th days of the cycle & continue for about 14 days. It is started by the ovulation and ended by menstruation (menstrual blood flow). It is coincides with the Luteal phase of the ovarian cycle.

Hormonal control of the post-proliferative phase Endometrial changes are under the control of the Luteal hormones particularly progesterone. In this stage there will be: 1. farther increase in the thickness of the endometrium (4 – 6 mm) to be ready for implantation. 2. Deposition of fat and glycogen in the endometrial cells so forming what is called as the decidual cells. 3. Increase in the blood flow of the endometrium. 4. The endometrial glands will become tortuous (Coiled & folded) and start to secret fluid (so the endometrium become edematous). The secreted fluid is used by the fertilized ovum as nutrients before implantation.

3. The destructive phase: Menstrual phase, Bleeding phase of the uterine cycle. last for 3 -5 days. If there is no fertilization of the ovum, The corpus luteum is matured by the 21 st day of the cycle, blood level of estrogen & progesterone negative feedback mechanism causing GTH (particularly LH). Regression of the corpus luteum (luteolysis). At the 24 th days of the cycle hormonal secretion at the 26 th - 28 th day of the cycle menstruation.

Mechanism of Menses estrogen Vasoconstriction of the spiral arteries Ischemic changes, Necrosis & shedding of the functional layers of the endometrium Hemorrhage Progesterone is liberated in the endometrium to facilitate shedding & sloughing. Shedding is complete within two days but bleeding continues 1 -3 days later and stopped by vasoconstriction of the spiral arteries.

Endometrium Regeneration after menses The deep pits of the endometrial glands are remaining intact during & after menstruation it will start a new epithelial growth. Within 5 days, the inner surface of the endometrium will cover the entire inner surface of uterus The amount of blood loss during menses is about 30 – 50 ml, (75 % is arterial blood) It is not clot due to the release of anticoagulant or Fibrinolysine from the damaged tissues. It contains also serous fluid.

Dysmenorrheal pain The blood with sloughed endometrial tissue as well as the serous fluid is about 200 ml in volume and they are called as the menstrum. If this menstrum is accumulated in the uterus it will cause intermittent myometrial contractions and cramps (pain) called dysmenorrheal pain (Painful menstruation).

• Cervical Cycle Regular changes in the cervical mucus which occur secondary to the ovarian cycle It is of two stages: 1. During the follicular phase: Estrogen from the Graafian follicle make the mucus thin, alkaline which promotes survival and motility of the sperms. Thinning & alkalinization reach the peak at the time of ovulation. 2. In the Luteal phase: Progesterone from the corpus luteum make the mucus thick and tenacious and it become more cellular.

• The vaginal cycle It is the regular changes of the vagina which follow the ovarian changes It is also of two stages: 1. In the follicular phase: Estrogen induces cornification of the vaginal epithelia. 2. In the Luteal phase: Progesterone induces proliferation of the epithelia & infiltration with leukocytes & secretion of thick mucus

• Estrous cycle Estrous means heat. It is the time of increased sexual desire and interest which occur at the time of ovulation. Some mammals do not menstruate and they have estrous cycle of variable duration. In dogs there is 2 cycles / year. In rat estrous cycle occurs every 4 – 6 days. In such animals ovulation occur: 1. Spontaneous as in rat. 2. Reflex as in rabbits & cats where ovulation occur during copulation.

None ovulatory cycle A menstrual cycle that is not associated with ovulation Normally occurs in the first 1 -2 years after puberty, and after menopause. Generally failure of ovulation may happen due to either lack of LH, or due to unresponsiveness of the ovary to the secreted LH. These cycles are shorter than normal cycle due the loss of the secretary phase, but they are usually regular and associated with sterility.

None ovulatory cycle In such cycle Graafian follicle is formed and there is secretion of estrogen but it will fail to initiate LH surge at mid of the cycle. So there is no ovulation, and corpus luteum is not formed. Eventually the mature follicle with its ovum will be degenerated, and the estrogen level will be decreased. This will cause vasoconstriction of the spiral arteries and menses will be ensured

• Identification of ovulation The tests include: 1. Clinical: a. Lower abdominal pain at mid of the cycle. b. Basal body temperature: 2. Endometrial biopsy: 3. Vaginal smear & or mucus of cervex: 4. Blood GTH: 5. Blood ovarian hormones: 6. Urinary ovarian hormones:

1. Clinical: a. Lower abdominal pain at mid of the cycle: Due to peritonitis as a result of minor bleeding with ovulation. b. Basal body temperature: Daily measurement of the body temperature (Morning) will show an increase of about 0. 5 C at the middle of the cycle indicating ovulation and increased basal metabolic rate, which will continues till menstruation. These changes may be due to the effect of progesterone.

2. Endometrial biopsy: Curettage in the second half of the cycle should show the presence of the secretary pattern which indicate ovulation. 3. Vaginal smear and or mucus of cervix: This will show the changes in the vagina, cervix, that occur in the second stage of cycle due to the effect of hormonal.

4. Blood GTH: Sudden and marked increase in the level of LH (LH surge) will occur at the middle of the cycle. 5. Blood ovarian hormones: Increased estrogen and progesterone level in the second half of the cycle. 6. Urinary ovarian hormones: Increased estrogen at the middle of the cycle, then 3 – 4 days latter progesterone excretion is increased as a metabolite (pregannediol).

Contraception Substances or means that suppress fertility They are used to control growth rate of the population. 1. Rhythmical method: Avoidance of intercourse at the period when fertilization is possible, (around the time of ovulation) Normally: Ova lives for about 72 h. & it is fertile for about 24 h. Sperm live for about 48 h. in the female genital tracts. Accordingly intercourse should be avoided for 4 – 5 days before and after suspected day of ovulation (9 th – 20 th day of the cycle). This method is not save with high failure rate.

2. Intra-uterine devise (IUD) Intra-uterine implantation of a foreign body (could be plastic spiral) IUD prevent fertilization by: 1. movement & contraction of uterus so prevent implantation. 2. Disturb the normal properties of the endometrium. High success rate with least side effect. The main problem: - Slipping of the device. - Infection. - Allergy. - Penetration of uterus during device implantation.

3. Contraceptive steroids: Large dose of estrogen or progesterone or combination of both together. These will inhibit the release of GTH from the pituitary gland. Estrogen: Inhibits FSH (interfere with normal follicular maturation) Progesterone: 1. Inhibits LH (prevent LH surge and so inhibit ovulation) 2. Makes the cervical mucus thick and so reduces sperm motility. It is of high success rate Side effects: 1. Water retention 2. Hypertension 3. thrombosis 4. incidence of carcinoma of the endometrium.

Abnormality of the ovarian function: 1. Ovarian disorders. 2. Pituitary disorders. 3. Hypothalamic disorders.

Abnormality of the ovarian function 1. Non-ovulatory cycle. 2. Abnormal menstrual cycle: A. Amenorrhea: Absence of menstrual period: which may: I. Primary (never occur), II. Secondary (occurs but stops later). B. Oligomenorrhea: Scanty, or little menstrual blood flow. C. Menorrhagia: Profuse or excess menstrual blood flow. D. Metrorrhagia: Uterine bleeding between the periods.

Abnormality of the ovarian function 3. Hypo-ovarianism: (female hypogonadism) It include reduction of both functions: 1. Gametogenesis 2. Endocrine function.

Clinical manifestation of female hypogonadism According to the age of onset and the severity of the defect: Defect occurs before puberty: - Congenital absence of the ovaries - Non-functioning pituitary gland - Diseases of the hypothalamus. There is no sexual maturation: Primary amenorrhea The subject is tall, sterile, and has infantile sex organs. Defect occurs after puberty: Secondary amenorrhea The subject will have decreased sex characters and atrophy of the sex organs, but not an infantile type.

Action of estrogen: 1. On the ovary: - Growth of follicle. - Formation of corpus luteum. - Ovulation by the effect of LH surge. 2. On the secondary sex organs: Uterus: - Stimulation of endometrial growth. 1. Stimulation of growth of the glands. 2. Increased blood flow. 3. Increased uterine muscles. 4. Increased motility of fallopian tube.

Action of estrogen: Cervix: The mucus will be thin, alkaline. Vagina: 1. Proliferation of the epithelia. 2. Cornification or keratinization. 3. Increased acidity of the vagina which is essential to reduce infection. External genitalia: 1. Increased growth of Bartholin's gland. 2. Increased growth of vulva and vagina. Mammary gland: 1. Breast enlargement. 2. Increased growth of the ducts. 3. Pigmentation of the areolas during pregnancy.

Action of estrogen: 3. On secondary sex characters: Feminizing characters: Includes body configuration, fat & hair distribution, psychic behavior and sexual desire. 4. On endocrine: - Produces –ve and +ve feedback on GTH. - Increase secretion of angiotensin from the liver. - Increase formation of thyroid binding globulin (TBG). - Increased secretion of androgen from the adrenal cortex. - Increased metabolism. - Premenstrual tension syndrome due to retention of water and electrolyte.