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Unformatted text preview: 1 Ch. 29 Prenatal Development Prenatal development includes: Fertilization (conception) Embryological development = the first 8 weeks post-fertilization Fetal development = from 9 weeks post- fertilization to birth Fig. 29-8b, p. 1102 Fig. 29-1a, p. 1089 Fertilization (conception) = the fusion of two haploid gametes one diploid zygote 1. The spermatozoon Is relatively small Carries the paternal DNA to the secondary oocyte 2. The secondary oocyte Is relatively large (~ 2,000X bigger than the sperm) Is in suspended animation in metaphase of meiosis II Contains maternal DNA, organ- elles, and enough nutrients to main- tain the zygote for about a week Usually occurs near the ampulla of the uterine tube 12-24 hours after ovulation Sperm reach the ampulla in 30 minutes to 2 hours Their journey may be aided by contractions of the uterus and uterine tube Fewer than 1% of ejaculated sperm reach the secondary oocyte 2 Fig. 28-8b, p. 1051 Fertilization: more about sperm Capacitation Even when they are mature in the ductus deferens, sperm are not yet motile or capable of fertilization (due...
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