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IN THE NAME OF GOD

IN THE NAME OF GOD. Female Hormonal Cycle MENSTRUAL CYCLE by : S. Rouholamin MD. Reproductive hormones: GnRH. GnRH: decapeptide, by neurons in arcuate nucleus of hypothalamus Regulate secretion of two hormones: FSH and LH Pulsatile secretion Extremely short half-life: only 2-4 min.

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IN THE NAME OF GOD

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  1. IN THE NAME OF GOD

  2. Female Hormonal CycleMENSTRUAL CYCLEby : S. Rouholamin MD

  3. Reproductive hormones: GnRH • GnRH: decapeptide, by neurons in arcuate nucleus of hypothalamus • Regulate secretion of two hormones: FSH and LH • Pulsatile secretion • Extremely short half-life: only 2-4 min

  4. Gonodotropins • LH &FSH: by ant pituitary gonadotroph cells • Ovarian follicular stimulation • Glycoproteins, alpha &beta subunit

  5. Prolactin • Poly peptide, by ant pituitary lactotroph • Primary trophic factor responsible for the synthesis of milk by breast • PRL secretion is under tonic inhibitory control by hypothalamic secretion of dopamine • PRL stimulation: breast manipulation, drugs, stress, exercise, certain foods

  6. TSH • By ant pituitary thyrotrophs in response to TRH • TRH:by arcuate nucleus ,portal circulation, pituitary • TRH: TSH & PRL release • Hypo- and hyperthyroidism: ovulatory dysfunction

  7. Oxytocin • 9 aa peptide, by paraventricular nucleus of hypothalamus • Uterine muscular contraction, breast lactiferous duct myoepithelial contraction

  8. MENSTRUAL CYCLE • Normal cycle length is considered 28 days • varies from female to female (21-35 days) • Ovarian cycle: 1-follicular ,2-luteal • Uterine cycle: 1-proliferative ,2-secreatory

  9. 1 – Follicular phase • Development dominant follicle, mature at midcycle, ovulation • Average length:10-14 days • Variability in length: variations in total cycle length

  10. 2-luteal phase • Ovulation to menses • Average length: 14 days

  11. Normal menstrual cycle • 21-35 days • 2-6 days of flow • Average blood loss:20-60 ml

  12. Hormonal variations • At the beginning of cycle: levels of gonadal steroids are low • Demise of corpus luteum, FSH levels rise, cohort of growing follicles is recruited, rise in estrogen: stimulus for uterine endometrial proliferation

  13. Hormonal variations • Rising estrogen levels: negative feedback on pituitary FSH secretion; growing follicle produce inhibin-B: suppresses pituitary FSH secretion; Rising estrogen levels: LH initially decreases but late in follicular phase LH levels increased dramatically

  14. Hormonal variations • At the end of follicular phase (just before ovulation) FSH-induced LH receptors on granulosa cells; with LH stimulation, modulate secretion of progesterone

  15. Hormonal variations • After sufficient degree of estrogenic stimulation; pituitary LH surge triggered, proximate cause of ovulation occurs 24 to 36 hours later

  16. Hormonal variations • Estrogen level decreases through the early luteal phase from just before ovulation until midluteal phase, rise again as a result of corpus luteum secretion

  17. Hormonal variations • Progesteron levels rise after ovulation; presumptive sign of ovulation • Progesteron;estrogen and inhibin-A : suppress gonadotropin secretion and new follicular growth

  18. Cyclic changes of the Endometrium • Decidua functionalis: 2/3 superficial, proliferate and shed each cycle • Decidua basalis: deepest region, source of endometrial regeneration after each menses

  19. 1-Proliferative phase • First day of vaginal bleeding :day 1 of the menstrual cycle • Progressive mitotic growth of decidua functionalis, preparation for implantation of embryo • Thin endometrium (1-2 mm); straight, narrow, short endometrial glands become longer, tortuous structures

  20. 2-Secretory phase • 48 to 72 hours following ovulation, progesteron secretion: eosinophilic protein-rich secretory product in glandular lumen • Postovulatory day 6-7,maximal secretory activity: optimal for implantation of blastocyst • Stromal edema in late secretory phase

  21. 2-Secretory phase • 2 days before menses:dramatic increases in PMN migrate from vascular system

  22. Menses • Absence of implantations, glandular secretion ceases, irregular break-down of decidua fuctionalis • Destruction of corpus luteum and its productions estrogen and progesteron: cause of shedding • Withdrawal of sex steroids: spiral art spasm, endometrial ischemia, lysosoms breakdown, proteolytic enzymes release

  23. Ovarian follicular development • Fetus:6-7 million in 20 wks • At birth:1-2 million • At puberty:300,000 • Release during ovulation:400-500 • At menopause:rare

  24. Oogonia: only one final daughter cell (oocyte), three polar body • Oocyte arrested in prophase (diploten) until time of ovulation

  25. Two-cell two-gonadotropin theory • with LH stimulation, the ovarian theca cells produce androgens that convert by granulosa cells into estrogens under the stimulus of FSH

  26. THE END

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