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Human Reproduction and Development. Starr/Taggart’s Biology: The Unity and Diversity of Life , 9e Chapter 45. Key Concepts:. The human reproductive system consists of a pair of gonads and accessory glands
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Human Reproductionand Development Starr/Taggart’s Biology: The Unity and Diversity of Life, 9e Chapter 45
Key Concepts: • The human reproductive system consists of a pair of gonads and accessory glands • In response to signals from the hypothalamus and the pituitary gland, gonads release sex hormones • Testosterone, LH, and FSH control male reproductive function
Key Concepts: • Human females are fertile on a cyclic basis • Estrogen, progesterone, FSH and LH are hormones that dominate cyclic activity • Human embryonic development starts with gamete formation and proceeds through different stages after fertilization
Sperm Formation • In testis • Seminiferous tubules • Spermatogenesis • Spermatocytes • Vas deferens • Glands • Prostate • Seminal vesicles • Bulbourethral
Hormonal ControlNegative Feedback Loop • Hypothalamus • GnRH • Anterior pituitary • LH, FSH • Leydig cells in testes • Testosterone
Menstrual Cycle Overview • Follicular Phase • Menstruation • Endometrium breakdown and buildup • Maturation of oocyte • Ovulation • Release of oocyte from ovary • Luteal Phase • Corpus luteum • Endometrium gets ready for pregnancy
Cyclic Changes in the Ovary • Granulosa cells • Follicle • Zona pellucida • Corpus luteum
Hormonal Control in the Menstrual Cycle • Hypothalamus • GnRH • Anterior Pituitary • FSH • LH • Ovaries • Estrogen • Progesterone
Changes in the Ovary and Uterus Hormonal changes Ovarian and Uterine changes
Fertilization • Sperm surround ovum • Cap releases acrosomal enzyme • Zona pellucida of ovum • One sperm penetrates • Oocyte completes meiosis II • Sperm and egg nuclei fuse • Zygote
Amniotic cavity Amnion Yolk sac Chorion Allantois Cells of blastocyst secrete HCG Stimulation of Corpus luteum Progesterone Estrogen Extra - Embryonic Membranes
Embryonic Period of Vertebrate • Primitive streak • Notochord • Brain and spinal cord
Maternal and Fetal Blood Circulation • Diffusion of O2, CO2 and other solutes
Fetus at 16 Weeks • Reflex actions • Limb differentiation
Nutrition Diet Extra vitamins Increased calories Infections Bacteria Rubella virus Prescription drugs Tranquilizers Barbiturates Anti-acne medication Antibiotics Alcohol Cocaine Cigarettes What Can Affect Development?
Birth • Labor • Oxytocin • Uterine contractions
Nourishing the Newborn • Lactation • Glands activated • Prolactin
AIDS HIV Gonorrhea Neisseria gonorrhoeae Syphillis Treponema pallidum Chlamydial Infection Chlamydia trachomatis Pelvic Inflammatory Disease Chlamydiaand Gonorrhea Genital Herpes Herpes simplex virus Genital warts Papilloma virus Sexually Transmitted Diseases
In Conclusion • Humans have reproductive organs which produce either sperm or oocytes • In males, the hormones LH, FSH, and testosterone control spermatogenesis • The hormones estrogen, progesterone, FSH, and LH control the maturation and release of oocytes
In Conclusion • A menstrual cycle includes a follicular phase, ovulation, and luteal phase • After fertilization, cleavage produces a blastocyst that implants in the endometrium • Four extraembryonic membranes form as the embryo develops: the amnion, yolk sac, chorion and blood vessels for the placenta
In Conclusion • The placenta allows embryonic blood vessels to develop independently from the mother’s allowing diffusion of nutrients and wastes • Nutritional deficiencies, infections, drugs, alcohol and cigarettes can affect the developing fetus • Mammary glands are stimulated by prolactin to produce milk after birth • developed by M. Roig