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Reproduction and Development
Chapter 26, part C Reproduction and Development
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Procreation: Delivering the Sperm to the Egg
Prevention: abstinence, barriers, surgical, & pills Phases of Coitus (sexual intercourse or copulation) Excitement Plateau Orgasm Resolution Erection Reflex CNS & spinal integration
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Procreation: Delivering the Sperm to the Egg
Figure 26-15: The erection reflex
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Fertilization: Union of Male & Female Chromosomes
Sperm capacitation Swimming & attractants Egg contact Penetration Nuclear fusion (Zygote) Figure 26-16b: Fertilization
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Fertilization: Union of Male & Female Chromosomes
Figure 26-17: Fusion of sperm and egg to form a zygote
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Zygote Development: Cell Division & Implantation
Cell divisions Blastocyst Migration to Uterus Implantation
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Zygote Development: Cell Division & Implantation
Figure 26-18: Ovulation, fertilization, and implantation of an ovum
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Placenta and Further Embroynic Development
Amnion Chorion Placenta Exchange Hormones Human chorionic Gonadotropin-hCG Progesterone
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Placenta and Further Embroynic Development
Figure a, b: The placenta
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Birth: Parturition Labor Rhythmic Uterine Contractions
Cervical dilation Delivery Baby Placenta
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Figure 26-20: Parturition: the birth process
Birth: Parturition Figure 26-20: Parturition: the birth process
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Regulators of Parturition
Labor onset Stretch stimulus Oxytocin Prostaglandins Positive feedback Stretch Oxytocin Birth ends Stimulus Figure 26-21: The positive feedback loop of parturition
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Lactation: Producing and Releasing Milk
Estrogen & progesterone Preps mammary tissues Prolactin inhibiting H: Prolactin milk production (other roles in fertility) Sucking stimulus Oxytocin "Milk let-down" reflex
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Lactation: Producing and Releasing Milk
Figure 26-23: The hormonal control of milk secretion and release
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Reproductive Maturation: Puberty
Increase production of sex hormones Maturation of reproductive organs & gamete production 20 sexual characteristics Males: pubic hair, beard, deep voice, "wedge" body form & muscle mass Females: menarche, pubic hair, breasts & "pear shape" body form
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Later in Life Menopause: Female "Change-of Life"
Ovaries responding to GnRH Levels of estrogen & progesterone produced Cease egg development "Hot flashes" , osteoporosis risk (hormone replacement debate) "Andropause" (?): Male changes are gradual Sex hormones: muscle mass, libido, erections Viagra: PNS NO cGMP degradation
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Summary Genes and hormones direct bipotential reproductive tissues to differentiate into males or females Spermatogenesis is regulated by FSH & LH, testosterone and inhibin influence on spermatocytes, Sertoli & Leydig cells Menstrual cycle coordinates egg maturation with endometrium, and is regulated by GnRH, LH & FSH estrogen, progesterone & inhibin (and placental hCG)
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Summary Fertilization, implantation, placental nutrition, lead to parturition (driven by oxytocin in a positive feedback reflex) Puberty initiates reproductive maturity, menopause the end of it
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