Physiology of the Female Reproductive System

Physiological Stages Neonatal period: birth---4 weeks Childhood: 4 weeks years Puberty: 12 years---18 years Sexual maturation: 18 year---50 year Perimenopause: decline of ovarian function (40 years)----1 year postmenopause Postmenopause: Neonatal period: birth---4 weeks Childhood: 4 weeks years Puberty: 12 years---18 years Sexual maturation: 18 year---50 year Perimenopause: decline of ovarian function (40 years)----1 year postmenopause Postmenopause:

Menstruation cyclic endometrium sheds and bleeds due to cyclic ovulation Mense 1.Endometrium is sloughed (progesterone withdrawal) 2.Nonclotting menstrual blood mainly comes from artery (75%) 3.Interval: days (28 days). duration: 2-6 days. the first day of menstrual bleeding is consideredy by day 1 4.Shedding: ml Menstruation cyclic endometrium sheds and bleeds due to cyclic ovulation Mense 1.Endometrium is sloughed (progesterone withdrawal) 2.Nonclotting menstrual blood mainly comes from artery (75%) 3.Interval: days (28 days). duration: 2-6 days. the first day of menstrual bleeding is consideredy by day 1 4.Shedding: ml

Central reproductive hormones Hypothalamus-Pituitary-Ovary(H-P-O axis)

Central reproductive hormones Neuroendocrine regulation 1.Gonadotropin-releasing hormone,GnRH 1)chemical structure (pro)Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH 2 2)Synthesize and transport Neuroendocrine regulation 1.Gonadotropin-releasing hormone,GnRH 1)chemical structure (pro)Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH 2 2)Synthesize and transport nerve cells hypothalamus portal vein pitutary anterior lobe

Central reproductive hormones

3)Regulation of GnRH Hypothalams GnRH Pituitary FSH, LH Ovary E,P

Central reproductive hormones 2.Gonadotropins 1)Composition (glycoprotein) Follicle stimulating hormone,FSH Luteinizing hormone,LH 2)Synthesize and transport 2.Gonadotropins 1)Composition (glycoprotein) Follicle stimulating hormone,FSH Luteinizing hormone,LH 2)Synthesize and transport Gonadotroph (pulse) Blood circulation ovary

Central reproductive hormones 3.Prolactin (PRL) Regulated by the prolactin inhibiting factor (PIF) 3.Prolactin (PRL) Regulated by the prolactin inhibiting factor (PIF)

The Ovarian cycle Function of ovary 1.Reproduction development and maturation of follicle; ovulation 2.Endocrine estrogens, progesterone, testosterone Function of ovary 1.Reproduction development and maturation of follicle; ovulation 2.Endocrine estrogens, progesterone, testosterone

The Ovarian cycle Cyclic changes of ovary 1.The development and maturation of follicle 1)Primordial follicle: before meiosis 2)Preantral follicle: zona pellucida, granulosa cells (FSH receptor) 3)Antral follicle: granulosa cells (LH receptor), E ↑ 4)Mature follicle: E ↑,P ↑ Theca externa, theca interna, granulosa, follicular antrum, mound, radiate coronal 5)Follicular phase: day 1 to follicle mature (14 days) Cyclic changes of ovary 1.The development and maturation of follicle 1)Primordial follicle: before meiosis 2)Preantral follicle: zona pellucida, granulosa cells (FSH receptor) 3)Antral follicle: granulosa cells (LH receptor), E ↑ 4)Mature follicle: E ↑,P ↑ Theca externa, theca interna, granulosa, follicular antrum, mound, radiate coronal 5)Follicular phase: day 1 to follicle mature (14 days)

The Ovarian cycle

2.Ovulation 1)First meiosis completed → collagen decomposed → oocyte ovulated 2)Regulation a)LH/FSH peak E 2 ↑( mature follicle ) → GnRH ↑ (hypothalamus) → LH/FSH peak (positive feedback) b)P cooperation LH ↑ → P ↑ (follicle luteinized before ovulation) → positive feedback 2.Ovulation 1)First meiosis completed → collagen decomposed → oocyte ovulated 2)Regulation a)LH/FSH peak E 2 ↑( mature follicle ) → GnRH ↑ (hypothalamus) → LH/FSH peak (positive feedback) b)P cooperation LH ↑ → P ↑ (follicle luteinized before ovulation) → positive feedback

The Ovarian cycle 3.Corpus luteum 1)follicle luteinized after ovulation: luteal cells 2)LH → VEGF → corpus hemorrhagicum 3)Regression non fertilized → corpus albicans 4)Luteal phase Ovulation to day 1 3.Corpus luteum 1)follicle luteinized after ovulation: luteal cells 2)LH → VEGF → corpus hemorrhagicum 3)Regression non fertilized → corpus albicans 4)Luteal phase Ovulation to day 1

The Ovarian cycle sex hormones secreted by ovary 1.Composition Estrogen, progesterone, testosterone 2.Chemical structure Steroid hormone 3.Synthesis Cholesterol → pregnenolone → androstenedione → testosterone → estradiol Δ 5 or Δ 4 pathway of estrogen production sex hormones secreted by ovary 1.Composition Estrogen, progesterone, testosterone 2.Chemical structure Steroid hormone 3.Synthesis Cholesterol → pregnenolone → androstenedione → testosterone → estradiol Δ 5 or Δ 4 pathway of estrogen production

The Ovarian cycle 4.Metabolism: liver 5.Cyclic change of E and P in ovary 1)Estrogen a)E ↑ (day 7) → E peak (pre-ovulate) → E ↓ → E ↑ (1 day after ovulate) → E peak (day 7-8) → E ↓ b)theca interna cells (LH receptor) → testosterone c)Granulosa (FSH receptor) → estrogen 4.Metabolism: liver 5.Cyclic change of E and P in ovary 1)Estrogen a)E ↑ (day 7) → E peak (pre-ovulate) → E ↓ → E ↑ (1 day after ovulate) → E peak (day 7-8) → E ↓ b)theca interna cells (LH receptor) → testosterone c)Granulosa (FSH receptor) → estrogen

The Ovarian cycle 2)Progesterone P ↑ (after ovulation) → P peak (day 7-8) → P ↓ 2)Progesterone P ↑ (after ovulation) → P peak (day 7-8) → P ↓ granulosa progesterone LH

Ovarian responses

The Ovarian cycle H-P-O axis 1.Positive feedback Sex hormones (E) ↑ → GnRH or LH/FSH ↑ E peak ( ≥200pg/ml ) → LH/FSH peak → ovulation 2.Negative feedback Sex hormones (E) ↑ → GnRH or LH/FSH ↓ Follicular phase: E ↑ → FSH ↓ Luteal phase: E ↑ P ↑ → LH/FSH ↓ (formation) E ↓ P ↓ → LH/FSH ↑ (regression) H-P-O axis 1.Positive feedback Sex hormones (E) ↑ → GnRH or LH/FSH ↑ E peak ( ≥200pg/ml ) → LH/FSH peak → ovulation 2.Negative feedback Sex hormones (E) ↑ → GnRH or LH/FSH ↓ Follicular phase: E ↑ → FSH ↓ Luteal phase: E ↑ P ↑ → LH/FSH ↓ (formation) E ↓ P ↓ → LH/FSH ↑ (regression)

The endometral cycle Proliferative phase 1.E ↑ (mitogen) → stroma thickens and glands become elongated → proliferative endometrium 2.Duration: 2 weeks 3.Thickness: 0.5mm → 5mm Proliferative phase 1.E ↑ (mitogen) → stroma thickens and glands become elongated → proliferative endometrium 2.Duration: 2 weeks 3.Thickness: 0.5mm → 5mm

The endometral cycle Secretory phase 1.P ↑ (differentiation) → secretory endometrium 2.Features stroma becomes loose and edematous blood vessels entering the endometrium become thickened and twisted glands become tortuous and contain secretory material within the lumina 3.Duration: 2 weeks 4.Thickness: 5-6mm Secretory phase 1.P ↑ (differentiation) → secretory endometrium 2.Features stroma becomes loose and edematous blood vessels entering the endometrium become thickened and twisted glands become tortuous and contain secretory material within the lumina 3.Duration: 2 weeks 4.Thickness: 5-6mm

Change of Other genital organs Cervix endocervical glands (E ↑ ) → mucus(thin,clear, watery) → maximal (ovulation) endocervical glands (P ↑ ) → mucus(thick, opaque, tenacious) Vagina Vaginal mucosa (E ↑)→ thickening and secretory changes Vaginal mucosa (P ↑ ) → secrete ↓ Cervix endocervical glands (E ↑ ) → mucus(thin,clear, watery) → maximal (ovulation) endocervical glands (P ↑ ) → mucus(thick, opaque, tenacious) Vagina Vaginal mucosa (E ↑)→ thickening and secretory changes Vaginal mucosa (P ↑ ) → secrete ↓

Physiological function of sex hormones Estrogen

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