Physiology of the Female Reproductive System

1
Physiology of the Female Reproductive System

• Liu Wei
• Department of Ob Gy
• Ren Ji hospital

2
Physiological 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

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Menstruation

• Menstruation
• cyclic endometrium sheds and bleeds due to
  cyclic ovulation
• Mense
• Endometrium is sloughed (progesterone withdrawal)
• Nonclotting menstrual blood mainly comes from
  artery (75)
• Interval 24-35 days (28 days). duration 2-6
  days. the first day of menstrual bleeding is
  consideredy by day 1
• Shedding 30-50 ml

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Central reproductive hormones

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

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Central reproductive hormones

• Neuroendocrine regulation
• Gonadotropin-releasing hormone,GnRH
• chemical structure
• (pro)Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly
  -NH2
• Synthesize and transport

nerve cells hypothalamus
portal vein pitutary
anterior lobe
6
Central reproductive hormones
7
Central reproductive hormones

• Regulation of GnRH

Hypothalams GnRH
Pituitary FSH, LH
Ovary E,P
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Central reproductive hormones

• Gonadotropins
• Composition (glycoprotein)
• Follicle stimulating hormone,FSH
• Luteinizing hormone,LH
• Synthesize and transport

ovary
Gonadotroph (pulse)
Blood circulation
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Central reproductive hormones

• Prolactin (PRL)
• Regulated by the prolactin inhibiting factor (PIF)

10
The Ovarian cycle

• Function of ovary
• Reproduction
• development and maturation of follicle
  ovulation
• Endocrine
• estrogens, progesterone, testosterone

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The Ovarian cycle

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

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The Ovarian cycle
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The Ovarian cycle

• Ovulation
• First meiosis completed ? collagen decomposed ?
  oocyte ovulated
• Regulation
• LH/FSH peak
• E2?(mature follicle) ? GnRH ? (hypothalamus) ?
  LH/FSH peak (positive feedback)
• P cooperation
• LH ? ? P ?(follicle luteinized before ovulation)
  ?positive feedback

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The Ovarian cycle

• Corpus luteum
• follicle luteinized after ovulation luteal cells
• LH ? VEGF ? corpus hemorrhagicum
• Regression
• non fertilized ? corpus albicans
• Luteal phase
• Ovulation to day 1

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The Ovarian cycle

• sex hormones secreted by ovary
• Composition
• Estrogen, progesterone, testosterone
• Chemical structure
• Steroid hormone
• Synthesis
• Cholesterol?pregnenolone?androstenedione?
• testosterone?estradiol
• ?5 or ?4 pathway of estrogen production

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The Ovarian cycle

• Metabolism liver
• Cyclic change of E and P in ovary
• Estrogen
• E?(day 7) ? E peak (pre-ovulate) ? E? ? E? (1 day
  after ovulate) ?E peak (day 7-8) ? E?
• theca interna cells (LH receptor) ? testosterone
• Granulosa (FSH receptor) ? estrogen

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The Ovarian cycle

• Progesterone
• P? (after ovulation) ? P peak (day 7-8) ? P?

granulosa
LH
progesterone
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Ovarian responses
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The Ovarian cycle

• H-P-O axis
• Positive feedback
• Sex hormones (E)? ? GnRH or LH/FSH?
• E peak (200pg/ml) ? LH/FSH peak ? ovulation
• 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)

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The endometral cycle

• Proliferative phase
• E?(mitogen)? stroma thickens and glands become
  elongated ? proliferative endometrium
• Duration 2 weeks
• Thickness 0.5mm ? 5mm

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The endometral cycle

• Secretory phase
• P?(differentiation) ? secretory endometrium
• 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
• Duration 2 weeks
• Thickness 5-6mm

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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?

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Physiological function of sex hormones

• Estrogen

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END