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Sex, Reproduction, & Development

Sex, Reproduction, & Development. Smoking and Pregnancy In The News. Types of Reproduction. Sexual reproduction Union of male & female gametes (sex cells) Each parent supplies half genetic material Asexual reproduction No union of gametes Cloning, unless there is mutation.

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Sex, Reproduction, & Development

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  1. Sex, Reproduction, & Development

  2. Smoking and PregnancyIn The News

  3. Types of Reproduction • Sexual reproduction • Union of male & female gametes (sex cells) • Each parent supplies half genetic material • Asexual reproduction • No union of gametes • Cloning, unless there is mutation

  4. Asexual Reproduction • Occurs in all 3 domains of life • Disadvantage • Genetic sameness means less survival with changing environments • Variability only due to mutation • Advantage • Individuals can reproduce

  5. Asexual Reproduction

  6. Binary Fission • Dividing of individual into two • Common in: • Archaea • Bacteria • Many protists

  7. Asexual Reproduction by Spores • Common in fungi • Life cycle with sexual & asexual stage

  8. Asexual Reproduction by Budding • Occurs in sponges, jellyfish & anemones

  9. Asexual Reproduction by Fragmentation • Occurs in flatworms & sea stars • Fragments regenerate new parts

  10. Parthenogenesis • Eggs develop without fertilization • Some species engage in behaviors simulating mating

  11. Sexual Reproduction • Prevalent among most vertebrates • Common in many invertebrates • Zygote • Fusion of haploid egg & sperm cells • Produces diploid cell

  12. Hermaphrodite • Both male & female in same body • Some can reproduce by self-fertilization • Forms of hermaphrodite • Simultaneous • Sequential

  13. Modes of Fertilization • External Fertilization • Female sheds eggs • Male fertilizes eggs after they leave her body

  14. Modes of Fertilization • Internal Fertilization • Male deposits sperm in or near the female reproductive tract • Eggs are fertilized in female’s body

  15. Human Reproduction • Sexual with internal fertilization • Gonads = reproductive organs • Male – testes • Female –ovaries • Other organs transport & receive sex cells • Accessory glands facilitate reproduction

  16. Production of Sperm • Testes • Housed in scrotum • Placement allows for development • Temperature must be lower than body

  17. Testes Structure • Composed of seminiferous tubules • Site of sperm production (spermatogenesis) • Sperm production triggered by follicle stimulating hormone • Spermatogonia give rise to sperm cells

  18. Spermatogenesis • Spermatogonia undergo mitosis • Some daughter cells undergo meiosis

  19. Epididymis • Site of sperm cell storage • 18 hours to 10 days • Unused sperm cells are reabsorbed

  20. Vas Defrens • Long tube from epididymis thru pelvic cavity • Loops over urinary bladder • Delivers sperm to urethra

  21. Accessory Glands • Seminal vesicle • Adds fructose to nourish sperm cells • Bicarbonate buffers acidity of urethra & vagina • Prostate • Alkaline fluid • Bulbourethral glands • Mucus-like alkaline substance • Lubricant for sexual intercourse

  22. Penis • Cylinders of erectile tissue

  23. Female Reproductive System • Vagina • Accepts penis & receives sperm • External genitals • Vulva • Mons pubis • Labia majora • Labia minora • Clitoris • Erectile tissue

  24. Ovaries • Female gonad • Contain primary oocytes • Can develop into eggs

  25. Oogenesis • One primary oocyte yields in one ovum & three polar bodies

  26. Oviducts • Ovulation – mature oocyte is released • Oocyte enters oviduct • Oviducts lead to uterus • Oviduct is site of fertilization

  27. Uterus • Cervix – lower portion opens to vagina • Uterus is site of prenatal development • Endometrium – inner lining • Nourishing layer for embryo • Shed monthly if no pregnancy occurs

  28. Reproductive Cycle

  29. Birth Control Methods

  30. Birth Control Methods

  31. Birth Control Methods

  32. Birth Control Methods

  33. Birth Control Methods

  34. Birth Control Methods

  35. Sexually Transmitted Diseases

  36. Sexually Transmitted Diseases

  37. Stages of Human Development • Zygote – fusion of egg & sperm • Embryo • Morula • Blastocyst • Implantation • Gastrulation • Neurulation • Fetus

  38. Morula • 1 cell zygote begins to divide rapidly • Mitosis without growth

  39. Blastocyst • Ball of cells • Portion of interior destined to differentiate • Cells begin to migrate (morphogenesis)

  40. Implantation • Approximately 1 week after fertilization • Blastocyst secretes enzymes • Digests portion of endometrial wall • Nourished by digested uterine cells

  41. Implantation • Embryo completes implantation • Germ layers begin development (first 2) • Ectoderm • Endoderm

  42. From Ovulation to Implantation

  43. Gastrulation • Primary germ layers fully formed • Organs & tissues begin development

  44. Neurulation • Development of hollow nerve cord • Neural groove forms

  45. Embryo at Four Weeks

  46. Fetus • All organ systems are formed • Growth & development continues

  47. Fetus at Five Months

  48. Human Fetus Near Full Term

  49. Birth is Initiated by Hormones

  50. Newborn Physiological Changes • Obtains oxygen from environment • Placenta no longer the source of nutrients • Blood circulation is increased to lungs

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