08 Embryology


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We did not go into as much detail as shown on these slides, but hopefully they will help.

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08 Embryology

  1. 1. Embryology McKinley and O’Laughlin Chapter 3
  2. 2. Introduction <ul><li>All of the bodies cells arise from the zygote (fertilized egg). </li></ul><ul><li>We get our ~100 trillion cells from Mitosis , the production of 2 genetically identical daughter cells from 1 parental cell. </li></ul>
  3. 3. Introduction <ul><li>What is the process which results in these cells specializing? </li></ul><ul><ul><li>Differentiation </li></ul></ul>
  4. 4. Introduction <ul><li>What is the 38-week period of development in the female reproductive system? </li></ul><ul><ul><li>Prenatal period </li></ul></ul><ul><ul><ul><li>A 40 week gestation period is measured from the woman's last period, not ovulation. </li></ul></ul></ul>
  5. 5. Introduction <ul><li>What is the study of development during this period (prenatal development)? </li></ul><ul><ul><li>Embryology </li></ul></ul>
  6. 6. Introduction <ul><li>What is the biological specialty that studies anatomical and physiological changes from the conception of a new individual to that individuals death? </li></ul><ul><ul><li>Developmental Biology </li></ul></ul>
  7. 7. Introduction <ul><li>What are the 3 periods of development from the moment of conception to birth? </li></ul><ul><ul><li>Pre-embryonic period </li></ul></ul><ul><ul><li>Embryonic period </li></ul></ul><ul><ul><li>Fetal period </li></ul></ul>
  8. 8. Gametogenesis <ul><li>What are haploid cells which are capable of producing a new diploid individual? </li></ul><ul><ul><li>Gametes </li></ul></ul>
  9. 9. Gametogenesis <ul><li>What are diploid cells which are distinguished from the gametes? </li></ul><ul><ul><li>Somatic cells </li></ul></ul>
  10. 10. Gametogenesis <ul><li>What is the distinguishing characteristic of human diploid cells? </li></ul><ul><ul><li>Carry 23 pairs of chromosomes </li></ul></ul><ul><ul><ul><li>We aren’t the only species with 23 pairs, but our closest relatives have 24 pairs. </li></ul></ul></ul>
  11. 11. Gametogenesis <ul><li>What is the distinguishing characteristic of human haploid cells? </li></ul><ul><ul><li>Carry 23 chromosomes </li></ul></ul><ul><ul><ul><li>1 member of each pair </li></ul></ul></ul><ul><ul><ul><li>Crossing over makes each chromosome different than those receive from parents </li></ul></ul></ul>
  12. 12. Gametogenesis <ul><li>What type of cell division produces haploid cells? </li></ul><ul><ul><li>Meiosis </li></ul></ul>
  13. 13. Gametogenesis <ul><li>Mitosis </li></ul><ul><li>2, diploid daughter cells </li></ul><ul><li>Meiosis </li></ul><ul><li>4, haploid daughter cells </li></ul><ul><li>Crossing over: Exchange of DNA between homologues </li></ul><ul><li>How do these 2 types of cell division (Mitosis and Meiosis) differ? </li></ul>
  14. 14. Meiosis I
  15. 15. Gametogenesis <ul><li>Where in the body does reduction division occur? </li></ul><ul><ul><li>Gonads </li></ul></ul>
  16. 16. Gametogenesis <ul><li>Why is reduction division so important? </li></ul>
  17. 17. Pre-embryonic Period <ul><li>What is the fertilized egg? </li></ul><ul><ul><li>Zygote </li></ul></ul>
  18. 18. Pre-embryonic Period <ul><li>What period of development ranges from the moment of conception until the completion of implantation into the uterine wall? </li></ul><ul><ul><li>Pre-embryonic </li></ul></ul>
  19. 19. Pre-embryonic Period <ul><li>What process restores the diploid number of chromosomes, determines the sex of an individual, and initiates cleavage? </li></ul><ul><ul><li>Fertilization </li></ul></ul>
  20. 21. Pre-embryonic Period <ul><li>Where does this process usually take place? </li></ul><ul><ul><li>Uterine tube (Ampulla) </li></ul></ul>
  21. 22. Pre-embryonic Period <ul><li>What series of synchronized mitotic divisions results in an increase in the number of cells? </li></ul><ul><ul><li>Cleavage </li></ul></ul>
  22. 23. Pre-embryonic Period <ul><li>What is the compacted 16-cell stage of development? </li></ul><ul><ul><li>Morula </li></ul></ul>
  23. 24. Pre-embryonic Period <ul><li>In what stage do the products of conception enter the uterus? </li></ul><ul><ul><li>Morula </li></ul></ul>
  24. 25. Pre-embryonic Period <ul><li>What stage of development occurs as fluids enter the products of conception (Morula at this point)? </li></ul><ul><ul><li>Blastocyst </li></ul></ul>
  25. 26. Pre-embryonic Period <ul><li>What are the two distinct components of this fluid-filled sphere? Which becomes the embryo? </li></ul><ul><ul><li>Trophoblast: becomes the chorion </li></ul></ul><ul><ul><li>Embryoblast: becomes the embryo </li></ul></ul>
  26. 29. Pre-embryonic Period <ul><li>What is the process by which this sphere burrows into and embeds within the endometrium? </li></ul><ul><ul><li>Implantation </li></ul></ul>
  27. 30. Pre-embryonic Period <ul><li>When does the process (Implantation) begin? </li></ul><ul><ul><li>~7 days after fertilization </li></ul></ul>
  28. 31. Pre-embryonic Period <ul><li>The inner cell mass (embryoblast) divides into two cell layers that form a flat disc. What is the anatomical term for this disc? </li></ul><ul><ul><li>Bilaminar germinal disc (blastodisc) </li></ul></ul>
  29. 33. Pre-embryonic Period <ul><li>What is the collective term for the membranes formed to mediate the exchange between the uterus and the embryo? </li></ul><ul><ul><li>Extraembryonic membranes </li></ul></ul>
  30. 34. Pre-embryonic Period <ul><li>Which membrane forms first and is involved in the formation of blood cells and blood vessels? </li></ul><ul><ul><li>Yolk sac </li></ul></ul>
  31. 35. Pre-embryonic Period <ul><li>Which membrane forms a fluid filled sac immediately around the embryo? </li></ul><ul><ul><li>Amnion </li></ul></ul>
  32. 36. Pre-embryonic Period <ul><li>Which membrane is outermost and eventually forms the placenta? </li></ul><ul><ul><li>Chorion </li></ul></ul>
  33. 38. Pre-embryonic Period <ul><li>What is the organ of exchange between the mother and the embryo? </li></ul><ul><ul><li>Placenta </li></ul></ul>
  34. 39. Pre-embryonic Period <ul><li>What 2 layers of tissue contribute to its formation? </li></ul><ul><ul><li>Fetal: Chorion </li></ul></ul><ul><ul><li>Maternal: Endometrium </li></ul></ul>
  35. 40. Pre-embryonic Period <ul><li>What structure initially connects the embryo to the organ of exchange? </li></ul><ul><ul><li>Connecting stalk </li></ul></ul>
  36. 41. Pre-embryonic Period <ul><li>What does this initial structure develop into? </li></ul><ul><ul><li>Umbilical cord </li></ul></ul>
  37. 42. Pre-embryonic Period <ul><li>What stalk-like structures form from the chorion? </li></ul><ul><ul><li>Chorionic villi </li></ul></ul>
  38. 44. Pre-embryonic Period <ul><li>In this organ of exchange (the placenta) do the mother’s blood and the embryo’s blood mix? </li></ul><ul><ul><li>No </li></ul></ul>
  39. 45. Pre-embryonic Period <ul><li>What is the common name for this organ of exchange (the placenta)? </li></ul><ul><ul><li>Afterbirth </li></ul></ul>
  40. 46. <ul><li>http://www-medlib.med.utah.edu/WebPath/PLACHTML/PLAC032.html </li></ul>
  41. 47. Embryonic Period <ul><li>What process results in the formation of three primary germ layers? </li></ul><ul><ul><li>Gastrulation </li></ul></ul>
  42. 48. Embryonic Period <ul><li>What are the three primary germ layers? </li></ul><ul><ul><li>Ectoderm </li></ul></ul><ul><ul><li>Mesoderm </li></ul></ul><ul><ul><li>Endoderm </li></ul></ul>
  43. 49. Embryonic Period <ul><li>When does the blastocyst become an embryo? </li></ul><ul><ul><li>During gastrulation (after implantation) </li></ul></ul><ul><ul><li>3rd week </li></ul></ul>
  44. 52. Embryonic Period <ul><li>What type of folding results in the formation of the head and buttocks? </li></ul><ul><ul><li>Cephalocaudal folding </li></ul></ul>
  45. 54. Embryonic Period <ul><li>What type of folding results in the formation of the torso? </li></ul><ul><ul><li>Transverse folding </li></ul></ul>
  46. 56. Embryonic Period <ul><li>What structures form from the ectoderm? </li></ul><ul><ul><li>Nervous system </li></ul></ul><ul><ul><li>Epidermis </li></ul></ul>
  47. 58. Embryonic Period <ul><li>What inductive action transforms a portion of the ectoderm into a hollow tube which develops into the nervous system? </li></ul><ul><ul><li>Neurulation </li></ul></ul>
  48. 61. Embryonic Period <ul><li>What structures form from the mesoderm? </li></ul><ul><ul><li>Muscle </li></ul></ul><ul><ul><li>Connective tissue </li></ul></ul><ul><ul><li>Urinary system </li></ul></ul><ul><ul><li>Reproductive system </li></ul></ul><ul><ul><li>Cardiovascular system </li></ul></ul><ul><ul><li>Lining of body cavities </li></ul></ul>
  49. 63. Embryonic Period <ul><li>What structures form from the endoderm? </li></ul><ul><ul><li>Linings of </li></ul></ul><ul><ul><ul><li>Digestive tract </li></ul></ul></ul><ul><ul><ul><li>Respiratory tract </li></ul></ul></ul><ul><ul><ul><li>Urinary tract </li></ul></ul></ul><ul><ul><li>Thyroid, parathyroids, thymus </li></ul></ul><ul><ul><li>Liver, gallbladder, pancreas </li></ul></ul>
  50. 65. Embryonic Period <ul><li>What is the process by which organs develop? </li></ul><ul><ul><li>Organogenesis </li></ul></ul>
  51. 66. Embryonic Period <ul><li>What are substances that may cause birth defects? </li></ul><ul><ul><li>Teratogens </li></ul></ul>
  52. 67. Fetal Period <ul><li>During what time period does the fetal period occur? </li></ul><ul><ul><li>Week 9 (3rd month) to birth </li></ul></ul>