IN THE NAME OF GOD

Female Horonal Cycle MENSTRUAL CYCLE E.Naghshineh MD

Reproductive hormons: 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

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

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

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

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

MENSTRUAL CYCLE varies from female to female (21-35 days) 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

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

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

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

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

3. 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

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

7.Progesteron levels rise after ovulation; presumptive sign of ovulation 8.Progesteron;estrogen and inhibin-A : suppress gonadotropin secretion and new follicular growth

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

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

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

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

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

2 days before menses:dramatic increases in PMN migrate from vascular system

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

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

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

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

THE END