Physiology of the Female Reproductive System

Physiology of the Female Reproductive System

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

function (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

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

• Postmenopause:

MenstruationMenstruation• Menstruation cyclic endometrium sheds and bleeds due

to cyclic ovulation• Mense1. Endometrium is sloughed (progesterone

withdrawal)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

withdrawal)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

Central reproductive hormones

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

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

Central reproductive hormones

Central reproductive hormones

• 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

pitutary

anterior lobe

Central reproductive hormones

Central reproductive hormones

Central reproductive hormones

Central reproductive hormones

3) Regulation of GnRH3) Regulation of GnRH

Hypothalams

GnRH

Pituitary

FSH, LH

Ovary

E,P

Central reproductive hormones

Central reproductive hormones

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

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

Gonadotroph (pulse)

Blood circulatio

n

ovary

Central reproductive hormones

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 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

antrum, 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

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

days)

The Ovarian cycleThe Ovarian cycle

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

decomposed → 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

decomposed → 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

The Ovarian cycleThe Ovarian cycle

3. Corpus luteum1) follicle luteinized after ovulation:

luteal cells2) LH → VEGF → corpus hemorrhagicum3) Regression non fertilized → corpus albicans4) Luteal phase Ovulation to day 1

3. Corpus luteum1) follicle luteinized after ovulation:

luteal cells2) 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→androstenedi

one→testosterone→estradiolΔ5 or Δ4 pathway of estrogen production

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

one→testosterone→estradiolΔ5 or Δ4 pathway of estrogen production

The Ovarian cycleThe Ovarian cycle

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

The Ovarian cycleThe Ovarian cycle

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

P↓

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

P↓

granulosa

progesterone

LH

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

Change of Other genital organs

Change of Other genital organs

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

watery) → 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,

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

opaque, tenacious)

• VaginaVaginal mucosa (E↑)→ thickening and

secretory changesVaginal mucosa (P↑) → secrete↓

Physiological function of sex hormones

Physiological function of sex hormones

• Estrogen• Estrogen

ENDEND