Physiology of the Female Reproductive System Liu Wei Department of Ob & Gy Ren Ji hospital Liu Wei...

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Physiology of the Female Reproductive System

Liu WeiDepartment of Ob & GyRen Ji hospital

Physiological StagesPhysiological Stages

• Neonatal period: birth---4 weeks• Childhood: 4 weeks----12 years• Puberty: 12 years---18 years• Sexual maturation: 18 year---50 year• Perimenopause: decline of ovarian func

tion (40 years)----1 year postmenopause

• Postmenopause:

• Neonatal period: birth---4 weeks• Childhood: 4 weeks----12 years• Puberty: 12 years---18 years• Sexual maturation: 18 year---50 year• Perimenopause: decline of ovarian func

tion (40 years)----1 year postmenopause

• Postmenopause:

MenstruationMenstruation• Menstruation cyclic endometrium sheds and bleeds due to cyclic

ovulation• Mense1. Endometrium is sloughed (progesterone withdra

wal)2. Nonclotting menstrual blood mainly comes from

artery (75%)3. Interval: 24-35 days (28 days). duration: 2-6 days.

the first day of menstrual bleeding is consideredy by day 1

4. Shedding: 30-50 ml

• Menstruation cyclic endometrium sheds and bleeds due to cyclic

ovulation• Mense1. Endometrium is sloughed (progesterone withdra

wal)2. Nonclotting menstrual blood mainly comes from

artery (75%)3. Interval: 24-35 days (28 days). duration: 2-6 days.

the first day of menstrual bleeding is consideredy by day 1

4. Shedding: 30-50 ml

Central reproductive hormones

• Hypothalamus-Pituitary-Ovary(H-P-O axis)

• Neuroendocrine regulation1. Gonadotropin-releasing hormone,GnRH1) chemical structure (pro)Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2

2) Synthesize and transport

• Neuroendocrine regulation1. Gonadotropin-releasing hormone,GnRH1) chemical structure (pro)Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2

2) Synthesize and transport

nerve cells

hypothalamus

portal vein

pitutaryanterior

3) Regulation of GnRH3) Regulation of GnRH

Hypothalams

Pituitary

FSH, LH

2. Gonadotropins1) Composition (glycoprotein) Follicle stimulating hormone,FSH Luteinizing hormone,LH2) Synthesize and transport

Gonadotroph (pulse)

Blood circulatio

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

The Ovarian cycleThe Ovarian cycle

• Function of ovary1. Reproduction development and maturation of

follicle; ovulation2. Endocrine estrogens, progesterone,

testosterone

• Function of ovary1. Reproduction development and maturation of

follicle; ovulation2. Endocrine estrogens, progesterone,

testosterone

The Ovarian cycleThe Ovarian cycle• Cyclic changes of ovary1. The development and maturation of follicle1) Primordial follicle: before meiosis2) 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 an

trum, mound, radiate coronal5) Follicular phase: day 1 to follicle mature (14 days)

• Cyclic changes of ovary1. The development and maturation of follicle1) Primordial follicle: before meiosis2) 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 an

trum, mound, radiate coronal5) Follicular phase: day 1 to follicle mature (14 days)

The Ovarian cycleThe Ovarian cycle2. Ovulation1) First meiosis completed → collagen decompo

sed → oocyte ovulated2) Regulationa) LH/FSH peakE2↑(mature follicle) → GnRH ↑ (hypothalamus)

→ LH/FSH peak (positive feedback)b) P cooperationLH ↑ → P ↑(follicle luteinized before ovulation)

→positive feedback

2. Ovulation1) First meiosis completed → collagen decompo

sed → oocyte ovulated2) Regulationa) LH/FSH peakE2↑(mature follicle) → GnRH ↑ (hypothalamus)

→ LH/FSH peak (positive feedback)b) P cooperationLH ↑ → P ↑(follicle luteinized before ovulation)

→positive feedback

3. Corpus luteum1) follicle luteinized after ovulation: luteal cell

s2) LH → VEGF → corpus hemorrhagicum3) Regression non fertilized → corpus albicans4) Luteal phase Ovulation to day 1

3. Corpus luteum1) follicle luteinized after ovulation: luteal cell

s2) LH → VEGF → corpus hemorrhagicum3) Regression non fertilized → corpus albicans4) Luteal phase Ovulation to day 1

The Ovarian cycleThe Ovarian cycle• sex hormones secreted by ovary1. Composition Estrogen, progesterone, testosterone2. Chemical structure Steroid hormone3. SynthesisCholesterol→pregnenolone→androstenedione

→testosterone→estradiolΔ5 or Δ4 pathway of estrogen production

• sex hormones secreted by ovary1. Composition Estrogen, progesterone, testosterone2. Chemical structure Steroid hormone3. SynthesisCholesterol→pregnenolone→androstenedione

→testosterone→estradiolΔ5 or Δ4 pathway of estrogen production

4. Metabolism: liver5. Cyclic change of E and P in ovary1) Estrogena) 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: liver5. Cyclic change of E and P in ovary1) Estrogena) 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

2) ProgesteroneP↑ (after ovulation) → P peak (day 7-8) →

granulosa

progesterone

Ovarian responsesOvarian responses

The Ovarian cycleThe Ovarian cycle• H-P-O axis1. Positive feedbackSex hormones (E)↑ → GnRH or LH/FSH↑E peak (≥200pg/ml) → LH/FSH peak → ovulation2. Negative feedbackSex 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 axis1. Positive feedbackSex hormones (E)↑ → GnRH or LH/FSH↑E peak (≥200pg/ml) → LH/FSH peak → ovulation2. Negative feedbackSex hormones (E)↑ → GnRH or LH/FSH↓Follicular phase: E↑ → FSH↓Luteal phase: E↑P↑ → LH/FSH↓(formation) E↓P↓ → LH/FSH↑(regression)

The endometral cycleThe endometral cycle• Proliferative phase1. E↑(mitogen)→ stroma thickens and glands

become elongated → proliferative endometrium

2. Duration: 2 weeks3. Thickness: 0.5mm → 5mm

• Proliferative phase1. E↑(mitogen)→ stroma thickens and glands

become elongated → proliferative endometrium

2. Duration: 2 weeks3. Thickness: 0.5mm → 5mm

The endometral cycleThe endometral cycle• Secretory phase1. P↑(differentiation) → secretory endometrium2. Featuresstroma becomes loose and edematousblood vessels entering the endometrium become

thickened and twistedglands become tortuous and contain secretory m

aterial within the lumina3. Duration: 2 weeks4. Thickness: 5-6mm

• Secretory phase1. P↑(differentiation) → secretory endometrium2. Featuresstroma becomes loose and edematousblood vessels entering the endometrium become

thickened and twistedglands become tortuous and contain secretory m

aterial within the lumina3. Duration: 2 weeks4. Thickness: 5-6mm

Change of Other genital organs

• Cervixendocervical glands (E↑)→ mucus(thin,clear, wa

tery) → maximal (ovulation)endocervical glands (P↑)→ mucus(thick, opaque

, tenacious)• VaginaVaginal mucosa (E↑)→ thickening and secretory

changesVaginal mucosa (P↑) → secrete↓

• Cervixendocervical glands (E↑)→ mucus(thin,clear, wa

tery) → maximal (ovulation)endocervical glands (P↑)→ mucus(thick, opaque

, tenacious)• VaginaVaginal mucosa (E↑)→ thickening and secretory

changesVaginal mucosa (P↑) → secrete↓

Physiological function of sex hormones

• Estrogen• Estrogen

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Physiology of the Female Reproductive System Liu Wei Department of Ob & Gy Ren Ji hospital Liu Wei...

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