1. Development and Inheritance

2. Embryo The first two months following fertilization The first two months following fertilization

3. Fetus From week nine until birth From week nine until birth

4. Pregnancy Lasts about 40 weeks from the first day of the last menstrual period Lasts about 40 weeks from the first day of the last menstrual period

5. Fertilization The genetic material from a haploid sperm cell and a haploid secondary oocyte merges into a single diploid nucleus The genetic material from a haploid sperm cell and a haploid secondary oocyte merges into a single diploid nucleus

6. Fertilization Occurs in the fallopian tube Occurs in the fallopian tube

7. Fertilization Occurs within 12-24 hours after ovulation Occurs within 12-24 hours after ovulation

8. Fertilization There is a total of 3 days per month during which coitus may result in pregnancy. There is a total of 3 days per month during which coitus may result in pregnancy.

9. Fertilization Two days before ovulation and one day after Two days before ovulation and one day after

10. Fertilization Peristaltic contractions and cilia transport the oocyte through the uterine tube Peristaltic contractions and cilia transport the oocyte through the uterine tube

11. Fertilization Sperm swim up the uterus and uterine tube by movements of their tails and muscular contractions of the uterus Sperm swim up the uterus and uterine tube by movements of their tails and muscular contractions of the uterus

12. Fertilization Only 200 of the 300 million spermatozoa reach the oocyte Only 200 of the 300 million spermatozoa reach the oocyte

13. Fertilization Capacitation – the functional changes that sperm undergo in the female that allow them to fertilize an oocyte Capacitation – the functional changes that sperm undergo in the female that allow them to fertilize an oocyte

14. Fertilization A sperm must penetrate the corona radiata and zona pellucida A sperm must penetrate the corona radiata and zona pellucida

15. Fertilization Acrosomal enzymes digest a path through the zona pelucida Acrosomal enzymes digest a path through the zona pelucida

16. Fertilization The spermatozoa that penetrates the oocyte loses its tail The spermatozoa that penetrates the oocyte loses its tail

17. Fertilization Polyspermy is prevented by chemical changes that penetrate a second sperm from entering the oocyte Polyspermy is prevented by chemical changes that penetrate a second sperm from entering the oocyte

18. Fertilization Once a sperm enters a secondary oocyte, the oocyte completes meiosis Once a sperm enters a secondary oocyte, the oocyte completes meiosis

19. Fraternal Twins Produced from the independent release of two ova and the subsequent fertilization of each by different spermatozoa Produced from the independent release of two ova and the subsequent fertilization of each by different spermatozoa

20. Monozygotic twins Derived from a single fertilized ovum that splits at an early stage in development Derived from a single fertilized ovum that splits at an early stage in development

21. Formation of the Morula Cleavage – early rapid mitotic cell division of a zygote Cleavage – early rapid mitotic cell division of a zygote

23. Formation of the Morula Blastomeres - The cells produced by cleavage Blastomeres - The cells produced by cleavage

24. Formation of the Morula Morula – A solid mass of 16-32 cells Morula – A solid mass of 16-32 cells

26. Development of the Blastocyst The morula moves down the ciliated uterine tube and into the uterine cavity The morula moves down the ciliated uterine tube and into the uterine cavity

27. Development of the Blastocyst The morula develops into a blastocyst The morula develops into a blastocyst

29. Development of the Blastocyst Blastocyst – a hollow ball of cells that is differentiated into a Blastocyst – a hollow ball of cells that is differentiated into a 1. Trophoblast 2. Inner cell mass 3. blastocele

30. Development of the Blastocyst Implantation – The attachment of a blastocyst to the endometrium seven to eight days after fertilization Implantation – The attachment of a blastocyst to the endometrium seven to eight days after fertilization

32. Development of the Blastocyst The trophoblast secretes human chorionic gonadotropin The trophoblast secretes human chorionic gonadotropin

33. Development of the Blastocyst hCG – rescues the corpus luteum from degeneration and sustains its function hCG – rescues the corpus luteum from degeneration and sustains its function

34. Development of the Blastocyst Trophoblast becomes the chorion Trophoblast becomes the chorion

35. Development of the Blastocyst Chorion – a membrane outside the amniotic sac that has villi which project into the placenta Chorion – a membrane outside the amniotic sac that has villi which project into the placenta

36. Beginnings of Organ Systems Gastrulation – inner cell mass of the blastocyst differentiates into three primary germ layers Gastrulation – inner cell mass of the blastocyst differentiates into three primary germ layers

37. Development of the Blastocyst Three primary germ layers Three primary germ layers 1. Ectoderm 2. Mesoderm 3. Endoderm

38. Embryonic Membranes Lie outside the embryo and protect and nourish the embryo and later, the fetus Lie outside the embryo and protect and nourish the embryo and later, the fetus

39. Embryonic Membranes 1. Yolk sac 2. Amnion 3. Chorion 4. allantois

40. Yolk Sac It gives rise to cells that migrate to the gonads to become spermatogonia and oogonia (ICM) It gives rise to cells that migrate to the gonads to become spermatogonia and oogonia (ICM)

41. Amnion Surrounds the embryo creating a cavity filled with amniotic fluid (ICM) Surrounds the embryo creating a cavity filled with amniotic fluid (ICM)

43. Chorion Derived from the trophoblast Derived from the trophoblast

44. Chorion Surrounds the embryo and later, the fetus Surrounds the embryo and later, the fetus

45. Chorion Embryonic part of the placenta Embryonic part of the placenta

47. Allantois Small vascularized membrane (ICM) Small vascularized membrane (ICM)

48. Allantois Umbilical cord Umbilical cord

50. Umbilical cord Vascular connection between mother and fetus Vascular connection between mother and fetus

51. Umbilical Cord Consists of two umbilical arteries carrying dexoygenated fetal blood to the placenta and one umbilical vein that carries oxygenated blood from the placenta into the fetus Consists of two umbilical arteries carrying dexoygenated fetal blood to the placenta and one umbilical vein that carries oxygenated blood from the placenta into the fetus

52. Placenta Developed by the third month of pregnancy Developed by the third month of pregnancy

53. Placenta Formed by the Formed by the 1. Chorion (embryonic portion) 2. Decidua basalis (maternal portion)

55. Placenta All exchanges to and from the embryo occur here All exchanges to and from the embryo occur here

56. Placenta Stores nutrients and released into fetal circulation as required Stores nutrients and released into fetal circulation as required

57. Hormones of Pregnancy During the first 3-4 months of pregnancy, the corpus luteum secretes progesterone and estrogen During the first 3-4 months of pregnancy, the corpus luteum secretes progesterone and estrogen

58. Hormones of Pregnancy Progesterone and estrogens maintain the uterine lining and prepare the mammary glands to secrete milk Progesterone and estrogens maintain the uterine lining and prepare the mammary glands to secrete milk

59. Hormones of Pregnancy After the third, the placenta secretes estrogen and progesterone After the third, the placenta secretes estrogen and progesterone

60. Hormones of Pregnancy Estrogen inhibits prolactin, so lactation does not occur Estrogen inhibits prolactin, so lactation does not occur

61. Hormones of Pregnancy Estrogen increases the number of oxytocin receptors in the uterus Estrogen increases the number of oxytocin receptors in the uterus

62. Hormones of Pregnancy Relaxin – softens the cervix and relaxes the pubic symphysis to facilitate delivery Relaxin – softens the cervix and relaxes the pubic symphysis to facilitate delivery

63. Hormones of Pregnancy Corticotropin-releasing hormone – the clock that establishes the timing of birth Corticotropin-releasing hormone – the clock that establishes the timing of birth

64. Anatomical and Physiological Changes During Pregnancy CO, HR, and SV increases CO, HR, and SV increases

65. Anatomical and Physiological Changes During Pregnancy Breast enlargement Breast enlargement

66. Anatomical and Physiological Changes During Pregnancy Increase in appetite Increase in appetite

67. Anatomical and Physiological Changes During Pregnancy Increase in tidal volume and total body oxygen consumption Increase in tidal volume and total body oxygen consumption

68. Anatomical and Physiological Changes During Pregnancy Increase in GFR Increase in GFR

69. Anatomical and Physiological Changes During Pregnancy Increase in frequency of urination Increase in frequency of urination

70. Anatomical and Physiological Changes During Pregnancy Some women experience elevated blood pressure Some women experience elevated blood pressure