Chapter 28: The Reproductive System Bio 211 lecture notes

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Chapter 28 The Reproductive SystemBio 211
lecture notes
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Gametogenesis

• Mitosis produces identical diploid cells
• Common all over the body
• Meiosis produces non-identical haploid cells
  (Gametes)
• Gametogenesis occurs in males inside the
  __________.
• Gametogenesis occurs in females inside the
  __________.

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Hormonal Regulation in Males
Figure 2812
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Hormonal Regulation of Ovarian Activity
Figure 2825
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Female Reproductive Cycle
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Aging and the Reproductive System

• Female reproductive system
• changes associated with menopause
• Male reproductive system
• changes associated with andropause
• occurs gradually, over longer time period

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Perimenopause

• Is the interval immediately preceding menopause
• Ovarian and uterine cycles become irregular
• due to shortage of primordial follicles
• estrogen levels decline
• ovulation is not triggered

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Menopause

• Circulating concentrations of estrogens and
  progesterone decline
• Production of GnRH, FSH, and LH rises sharply b/c
  Estrogen levels decline

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Decline in Estrogen Levels

• Leads to
• reduction in uterus and breast size
• thinning of urethral and vaginal epithelia
• reduction in bone deposition (osteoporosis)

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Andropause

• Also called male climacteric
• Is the period of declining reproductive function
• Circulating testosterone begins to decline
  between ages 50-60
• Circulating FSH and LH increase
• Sperm production continues
• Sexual activity gradually decreases with
  declining testosterone levels

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Successful Function of Male Reproductive System

• Sperm count must be adequate
• Semen must have correct pH and nutrients
• Erection and ejaculation must function properly

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Successful Function of Female Reproductive System

• Ovarian and uterine cycles must coordinate
  properly
• Ovulation and oocyte transport must occur
  normally
• Environment of reproductive tract must support
• survival and movement of sperm
• fertilization of oocyte