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The Reproductive System Anatomy of the reproductive system Hormonal control

The Reproductive System Anatomy of the reproductive system Hormonal control Fertilization and development Contraception “Assisted reproduction”. Formation of gametes Sperm Eggs Fertilization- fusion of gametes zygote Zygote divides repeatedly; differentiates

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The Reproductive System Anatomy of the reproductive system Hormonal control

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  1. The Reproductive System • Anatomy of the reproductive system • Hormonal control • Fertilization and development • Contraception • “Assisted reproduction”

  2. Formation of gametes Sperm Eggs Fertilization- fusion of gametes zygote Zygote divides repeatedly; differentiates into unique cells and tissues

  3. Features of reproductive system Gonads produce gametes and hormones ducts to trasnport the gametes accessory glands and organs (secrete fluids) external genitalia

  4. Testes are formed in abdomen and descend into scrotum at 7th month of development Temperature in scrotum is slightly lower than in body Spermatogenesis (formation of sperm) sperm-forming cells Sertoli cells interstitial cells-produce testosterone Process takes about 9 weeks

  5. Spermatazoa in testes are not yet capable of fertilization Epididymis- is actually over 20 feet long! spermatazoa complete maturation as they move through epididymis (about 2 weeks)  Ductus deferens (vas deferens)  Ejaculatory duct

  6. Ejaculatory duct Sperm Seminal fluid secretions from prostate seminal vesicles bulbourethral glands (Cowper’s glands) Activate sperm Provide nutrients Contractions help move sperm Buffers

  7. Control of erection Hypothalamus (conscious control) Parasympathetic nerves neurotransmitter- nitric oxide? promotes blood flow into penis (Viagra- promotes vasodilation) Control of emission and ejaculation sympathetic nerves- muscle contraction

  8. Female reproductive system Ovaries Accessory organs uterus uterine (Fallopian) tubes vagina external genitalia

  9. Hormonal control of the female reproductive cycle Pituitary and gonadal hormones Must coordinate ovarian and uterine cycles

  10. Evaluation of contraceptive methods Do they work? Are they safe? Are they available? Are they affordable? Do they protect against sexually transmitted diseases (STDs)

  11. Abstinence Surgical sterilization essentially permanent

  12. Oral contraception Prevents ovulation Is reversible Does NOT protect against STDs

  13. Risks of oral contraception Requires discipline Antibiotics can inhibit effect Can increase risk of heart attack or stroke can promote clot formation (estrogen) can promote atherosclerosis (progesterone) Can promote vaginal and cervical infections Can promote cervical cancer from HPV

  14. Progesterone-only contraceptives may be a little safer but not quite as effective Minipill (every day) Depo-Provera (3 months) Norplant (5 years)

  15. Is there a male pill? Strategies: shut off testosterone lowers sperm count, but linked with reduced sex drive and erectile dysfunction supplemental dose of testosterone Inhibit FSH? high rate of permanent sterility Inhibit GnRH? does not completely inhibit sperm production in everyone, but is reversible Answer: not yet

  16. IUD Safe and effective Risk of inflammatory disease, and subsequent sterility Recommended for women who don’t want future pregnancy or are not at risk for STD

  17. Barrier methods Diaphragms Cervical caps Condoms (male and female) Spermicides Not as effective in pregnancy prevention Do provide protection against STDs Availability

  18. Fertility awareness (“natural family planning”) Minute knowledge of woman’s cycle Indicators of ovulation body temperature cervical mucus

  19. Future methods? Vaccines against sperm, eggs, hCG, hormones Diaphragms with spermicide Vaginal rings with progestins Skin patches

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