BIO 120 Chapter 46

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BIO 120 Chapter 46
2010-12-10 21:43:29
BIO animal reproduction

Chapter 46 Animal Reproduction
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  1. Most eukaryotes reproduce how
  2. What are the positive and negative effects of asexual reproduction?
    gives many offspring (positive), but are genetically identical (negative)
  3. Why do testes hang outside the body?
    Normal sperm production can't occur at body temperature
  4. What is the only way the egg goes through Meiosis II?
    If sperm fertilizes the egg
  5. GnRH
    "big boss" hormone
  6. Sexual reproduction
    creation of an offspring by fusion of a male gamete (sperm) and female gamete (egg) to form a zygote
  7. Asexual reproduction
    creation of offspring without the fusion of egg and sperm
  8. Ovulation
    release of mature eggs at the midpoint of female cycle
  9. Hermaphroditism
    each individual has male and female reproductive systems
  10. Fertilization
    can occur externally or internally
  11. Ensuring the survival of offspring
    all species produces more offspring than the number that can survive
  12. Human reproduction
    Reproductive organs produce and transport gametes
  13. Female anatomy: ovaries
    • Contains many follicles
    • partially developed egg (oocyte) surrounded by support cells
  14. Oocyte
    develops into ovum (egg) by process of oogenesis
  15. If egg is fertilized after ovulation:
    Remaining follicular tissue forms corpus luteum, which secretes hormones to help maintain pregnancy
  16. If egg is not fertilized:
    corpus luteum degenerates
  17. Male anatomy: testes
    • Sperm form in seminiferous tubules
    • Leydig cells produce hormones; scattered between tubules
    • normal sperm production can't occur at body temperature of most mammals
  18. Gametogenesis
    production of gametes
  19. Spermatogenesis
    production of mature sperm
  20. Oogenesis
    production of mature egg
  21. Gonadotropin-releasing hormone (GnRH)
    • secreted by hypothalamus
    • directs release of follicle-stimulation hormone (FSH) and luteinizing hormone (LH)
  22. FSH and LH
    regulate gametogenesis and regulate sex hormone production
  23. Sex hormones
    androgens, estrogens, and progesterone
  24. Sex hormones regulate:
    • The development of primary sex characteristics during embryogenesis
    • The development of secondary sex characteristics at puberty
    • Sexual behavior and sex drive
  25. Menstruation
    shedding of endometrium (lining of the uterus)
  26. Hormones closely link the two cycles of female reproduction:
    • changes in the uterus define the menstrual cycle (aka the uterine cycle)
    • changes in the ovaries define the ovarian cycle
  27. Menopause
    • after about 500 cycles, human females undergo menopause
    • mood changes/heat flashes occur from hormonal changes
  28. Menopause
    the cessation of ovulation and menstruation
  29. Cleavages
    early cell divisions
  30. Development: conception
    • monozygote = one fertilized egg - it splits after fertilization from 1 sperm
    • dizygotic = 2 eggs got released, fertilized by different sperm
  31. Development: First trimester
    • begins when egg is released (period)
    • implantation
    • formation of placenta from trophoblast
    • organogenesis
    • becomes fetus at 8 weeks
  32. Human gestation
    takes roughly 40 weeks
  33. Development: Second trimester
    • mostly about growing
    • chances of miscarriage lowers
    • the fetus grows and is very active
    • the mother may feel fetal movements
    • the uterus grows enough for the pregnancy to become obvious (baby bump!)
  34. Development: Third trimester
    oxytocin causes contraction, which stimulates more oxytocin. This continues until they get harder and more frequent, and the baby comes out.
  35. Conception
    • vasectomy - guy gets vas deferons but (no sperm)
    • birth control - prevents ovulation
    • abstinence
    • condoms
    • coitus interruptus - fails. aka pull and pray method
    • tubal ligation - blocking fallopian tubes (similar to vasectomy for females)
    • preogestin only pill, spermicides, cervical cap
    • morning after pill - causes big spike in hormones, inducing uterine shedding