Female Hormonal CycleFemale Hormonal CycleMENSTRUAL CYCLEMENSTRUAL CYCLE

by : S. Rouholamin MD

Female Hormonal CycleFemale Hormonal CycleMENSTRUAL CYCLEMENSTRUAL CYCLE

by : S. Rouholamin MD

Reproductive hormones: Reproductive hormones: GnRHGnRH

GnRH: decapeptide, by neurons in GnRH: decapeptide, by neurons in arcuate nucleus of hypothalamus arcuate nucleus of hypothalamus

Regulate secretion of two hormones: Regulate secretion of two hormones: FSH and LHFSH and LH

Pulsatile secretionPulsatile secretion Extremely short half-life: only 2-4 minExtremely short half-life: only 2-4 min

GonodotropinsGonodotropins

LH &FSH: by ant pituitary LH &FSH: by ant pituitary gonadotroph cellsgonadotroph cells

Ovarian follicular stimulationOvarian follicular stimulation Glycoproteins, alpha &beta subunit Glycoproteins, alpha &beta subunit

ProlactinProlactin

Poly peptide, by ant pituitary Poly peptide, by ant pituitary lactotrophlactotroph

Primary trophic factor responsible for Primary trophic factor responsible for the synthesis of milk by breastthe synthesis of milk by breast

PRL secretion is under tonic PRL secretion is under tonic inhibitory control by hypothalamic inhibitory control by hypothalamic secretion of dopaminesecretion of dopamine

PRL stimulation: breast manipulation, PRL stimulation: breast manipulation, drugs, stress, exercise, certain foodsdrugs, stress, exercise, certain foods

TSHTSH

By ant pituitary thyrotrophs in By ant pituitary thyrotrophs in response to TRHresponse to TRH

TRH:by arcuate nucleus ,portal TRH:by arcuate nucleus ,portal circulation, pituitarycirculation, pituitary

TRH: TSH & PRL releaseTRH: TSH & PRL release Hypo- and hyperthyroidism: Hypo- and hyperthyroidism:

ovulatory dysfunctionovulatory dysfunction

Oxytocin Oxytocin

9 aa peptide, by paraventricular 9 aa peptide, by paraventricular nucleus of hypothalamus nucleus of hypothalamus

Uterine muscular contraction, Uterine muscular contraction, breast lactiferous duct breast lactiferous duct myoepithelial contractionmyoepithelial contraction

MENSTRUAL CYCLEMENSTRUAL CYCLE

Normal cycle length is considered 28 daysNormal cycle length is considered 28 days

varies from female to female (21-35 varies from female to female (21-35

days)days)

Ovarian cycle: 1-follicular ,2-lutealOvarian cycle: 1-follicular ,2-luteal

Uterine cycle: 1-proliferative ,2-secreatoryUterine cycle: 1-proliferative ,2-secreatory

1 – Follicular phase1 – Follicular phase

Development dominant follicle, Development dominant follicle, mature at midcycle, ovulationmature at midcycle, ovulation

Average length:10-14 daysAverage length:10-14 days Variability in length: variations in Variability in length: variations in

total cycle lengthtotal cycle length

2-luteal phase2-luteal phase

Ovulation to mensesOvulation to menses Average length: 14 daysAverage length: 14 days

Normal menstrual Normal menstrual cyclecycle

21-35 days21-35 days 2-6 days of flow2-6 days of flow Average blood loss:20-60 Average blood loss:20-60

mlml

Hormonal Hormonal variationsvariations

1.1. At the beginning of cycle: levels At the beginning of cycle: levels of gonadal steroids are low of gonadal steroids are low

2.2. Demise of corpus luteum, FSH Demise of corpus luteum, FSH levels rise, cohort of growing levels rise, cohort of growing follicles is recruited, rise in follicles is recruited, rise in estrogen: stimulus for uterine estrogen: stimulus for uterine endometrial proliferation endometrial proliferation

3.3. Rising estrogen levels: negative Rising estrogen levels: negative feedback on pituitary FSH secretion; feedback on pituitary FSH secretion;

growing follicle produce inhibin-B: growing follicle produce inhibin-B: suppresses pituitary FSH secretion;suppresses pituitary FSH secretion;

Rising estrogen levels: LH initially Rising estrogen levels: LH initially decreasesdecreases

but late in follicular phase LH levels but late in follicular phase LH levels increased dramaticallyincreased dramatically

Hormonal Hormonal variationsvariations

4.4. At the end of follicular phase At the end of follicular phase (just before ovulation) FSH-(just before ovulation) FSH-induced LH receptors on induced LH receptors on granulosa cells;granulosa cells;

with LH stimulation, modulate with LH stimulation, modulate secretion of progesteronesecretion of progesterone

Hormonal Hormonal variationsvariations

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

Hormonal Hormonal variationsvariations

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

Hormonal Hormonal variationsvariations

7.7. Progesteron levels rise after Progesteron levels rise after ovulation; presumptive sign ovulation; presumptive sign of ovulationof ovulation

8.8. Progesteron;estrogen and Progesteron;estrogen and inhibin-A : suppress inhibin-A : suppress gonadotropin secretion and gonadotropin secretion and new follicular growthnew follicular growth

Hormonal Hormonal variationsvariations

Cyclic changes of the Cyclic changes of the EndometriumEndometrium

Decidua functionalis: 2/3 Decidua functionalis: 2/3 superficial, proliferate and shed superficial, proliferate and shed each cycleeach cycle

Decidua basalis: deepest region, Decidua basalis: deepest region, source of endometrial source of endometrial regeneration after each menses regeneration after each menses

1-Proliferative phase1-Proliferative phase

First day of vaginal bleeding :day 1 First day of vaginal bleeding :day 1 of the menstrual cycleof the menstrual cycle

Progressive mitotic growth of Progressive mitotic growth of decidua functionalis, preparation for decidua functionalis, preparation for implantation of embryoimplantation of embryo

Thin endometrium (1-2 mm); Thin endometrium (1-2 mm); straight, narrow, short endometrial straight, narrow, short endometrial glands become longer, tortuous glands become longer, tortuous structuresstructures

2-Secretory phase2-Secretory phase

48 to 72 hours following ovulation, 48 to 72 hours following ovulation, progesteron secretion: eosinophilic progesteron secretion: eosinophilic protein-rich secretory product in protein-rich secretory product in glandular lumen glandular lumen

Postovulatory day 6-7,maximal Postovulatory day 6-7,maximal secretory activity: optimal for secretory activity: optimal for implantation of blastocystimplantation of blastocyst

Stromal edema in late secretory Stromal edema in late secretory phasephase

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

2-Secretory phase2-Secretory phase

MensesMenses

Absence of implantations, glandular Absence of implantations, glandular secretion ceases, irregular break-down secretion ceases, irregular break-down of decidua fuctionalisof decidua fuctionalis

Destruction of corpus luteum and its Destruction of corpus luteum and its productions estrogen and progesteron: productions estrogen and progesteron: cause of sheddingcause of shedding

Withdrawal of sex steroids: spiral art Withdrawal of sex steroids: spiral art spasm, endometrial ischemia, spasm, endometrial ischemia, lysosoms breakdown, proteolytic lysosoms breakdown, proteolytic enzymes release enzymes release

Ovarian follicular Ovarian follicular developmentdevelopment

Fetus:6-7 million in 20 wksFetus:6-7 million in 20 wks At birth:1-2 millionAt birth:1-2 million At puberty:300,000At puberty:300,000 Release during ovulation:400-500Release during ovulation:400-500 At menopause:rareAt menopause:rare

Oogonia: only one final daughter Oogonia: only one final daughter cell (oocyte), three polar bodycell (oocyte), three polar body

Oocyte arrested in prophase Oocyte arrested in prophase (diploten) until time of ovulation(diploten) until time of ovulation

with LH stimulation, the with LH stimulation, the ovarian theca cells produce ovarian theca cells produce androgens that convert by androgens that convert by granulosa cells into estrogens granulosa cells into estrogens under the stimulus of FSHunder the stimulus of FSH

Two-cell two-gonadotropin Two-cell two-gonadotropin theorytheory