BIOL432 Early Development

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  1. What 3 things make Ontogeny significant?
    • Inherited Information
    • Selection acts as a Filter
    • Embryo has own adaptations
  2. What two things make Hox Genes significant?
    • Major regulatory genes.
    • Highly conserved throughout animal kingdom.
  3. What type of cleavage occurs in all Vertebrates?
  4. Cleavage is affected by what?
    Relative quality of yolk.
  5. What does Holoblastic mean?
    Total Cleavage of Blastula.
  6. What does Meroblastic mean?
    Partial Cleavage of Blastula.
  7. What does Microlecithal mean and what kind of cleavage (holoblastic/meroblastic) is it associated with?
    Microlecithal means little yolk; holoblastic.
  8. What does Mesolecithal mean and what kind of cleavage (holoblastic/meroblastic) is it associated with?
    Mesolecithal means moderate yolk; holoblastic.
  9. What does Macrolecithal mean and what kind of cleavage (holoblastic/meroblastic) is it associated with?
    Macrolecithal means lots of yolk; meroblastic.
  10. Give 2 examples of Microlecithal.
    • Mammals
    • Amphioxus
  11. Give 2 examples of Mesolecithal.
    • Primitive Fish
    • Amphibians
  12. Give 2 examples of Macrolecithal.
    • Most fish
    • Reptiles
    • Birds
  13. What is the problem encountered with Macrolecithal?
    Due to lots of yolk, cleavage does not occur uniformly.
  14. What is the Gastrula?
    Embryo with 2-3 layers.
  15. What are the 3 main body tissues of development?
    • Ectoderm
    • Mesoderm
    • Endoderm
  16. What group is used as an outgroup regarding the formation of the gastrula and development of 3 main body tissues?
  17. Amphioxus are part of what group?
  18. What is a Coelom?
    Any space or cavity
  19. How does the Gastrocoel form in Amphioxus?
  20. How does the Mesoderm form in Amphioxus?
  21. How does Enterocoely form Gastrocoel?
    Forms it by little out-pockets.
  22. What is the Gastrocoel?
    The first opening
  23. How does the gastrocoel form in Amphibians and Primivite Fishes?
  24. How does the Mesoderm form in Amphibians and Primitive Fishes?
  25. Involution is also known as what and define its process.
    Aka Epiboly; cells migrate over the end & inward pushing the blastocoel further in.
  26. What does "schizo" mean?
  27. How does the Gastrocoel form in Fishes, Reptiles, & Birds?
    Ingression along the primitive streak
  28. How does the Mesoderm in Fishes, Reptiles, and Birds form?
  29. Why are Mammals considered special in developmental terms when compared to the other groups mentioned?
  30. List the steps of development in mammals.
    • Inner cell mass delaminates to form bilaminar embryo.
    • Gastrocoel forms by ingression along primitive streak.
    • Mesoderm forms by schizocoely.
  31. What structure is unique to mammals in development?
  32. What does the Trophoblast do?
    Gives rise to placenta
  33. What is the Neurula?
    Embryo with neural tube and regionalized mesoderm.
  34. How does the Neurula form?
    Ectodermal neural folds form, rise and meet in center to form tube.
  35. What are the three longitudinal divisions of the Mesoderm?
    • Epimere
    • Mesomere
    • Hypomere
  36. What are the three components of the Epimere?
    • Scleratome
    • Dermatome
    • Myotome
  37. What is the Epimere also known as?
  38. What is the Mesomere also known as?
    Nephric Ridge
  39. The Mesomere gives rise to what?
    • Kidneys
    • Urogential Ducts
  40. What is the Hypomere also known as?
    Lateral Plate Mesoderm
  41. What two components make up the Hypomere?
    • Splanchnopleure
    • Somatopleure
  42. What is the Splanchnopleure composed of?
    Endoderm & Mesoderm
  43. What is the Somatopleure composed of?
    Ectoderm & Mesoderm
  44. The Splanchnopleure is related to what?
    Guts / Viscera
  45. The Somatopleure is related to what?
    Everything other than the Guts / Viscera
  46. What is the Mesenchyme?
    Embryonic connective tissue
  47. The Ectoderm gives rise to what?
    • Epidermal Placodes
    • Neural Crest
  48. What does the Epidermal Placode give rise to?
    Parts of sense organs.
  49. What does the Neural Crest give rise to?
    • Parts of Nervous System
    • Head Skeleton
    • Visceral Cartilages
    • Adrenal Medulla
    • Pigment Cells
    • Sensory Nerves
  50. What two things are unique to Vertebrates?
    • Epidermal Placodes
    • Neural Crest
  51. General Ectoderm is broken down into what 3 components?
    • Epidermal ectoderm
    • Neural plate ectoderm
    • Neural crest ectoderm
  52. The Epidermal ectoderm gives rise to what?
  53. The Neural plate ectoderm gives rise to what?
    Nervous System
  54. The Neural Crest Ectoderm gives rise to what?
    Visceral skeleton
  55. The General Mesoderm is broken down into what 3 components?
    • Epimere
    • Mesomere
    • Hypomere
  56. The Epimere gives rise to what?
    • Dermis
    • Body muscularization
    • Vertebral column
  57. The Endoderm gives rise to what?
    The Gut, Gut Tube, and all its derivates
  58. What are the membranes called that are not part of the Embryo?
    Extraembryonic Membranes
  59. What are the 4 Extraembryonic Membranes?
    • Amnion
    • Chorion
    • Allantois
    • Yolk sac
  60. What 3 animal groups have Amnion?
    • Birds
    • Reptiles
    • Mammals
  61. Why is the Amnion so important?
    This layers makes the embryo free of needing to be in a sea environment.
  62. Describe the Chorion and its functions.
    Highly vascularized; adheres to inner part of the eggs and is used for exchange of gases (respiration)
  63. What is the function of the Allantois?
    Storage of Nitrogen (Waste)
  64. What is the function of the Yolk Sac?
    Nutrition for the embryo
  65. List the steps of the development of extraembryonic membranes for Reptiles and Birds.
    • Amniotic folds rise around embryo resulting in a distinct amnion.
    • Extraembryonic mesoderm splits resulting in a chorion.
    • Outpocketing of gut into splanchnic mesoderm produces allantois.
    • Connection between embryo and yolk sac develops as the yolk stalk.
  66. List the development of Extaembryonic Membranes in Mammals.
    • Same as birds and reptiles except:
    • Chorioallantoic placenta develops as intimate juxtaposition of fetal and maternal tissues from chorionic villi and allantoic vessels.
    • Smaller emphasis on yolk sac (microlecithal) so yolk stalk becomes umbilical cord; blood vessels transport food & oxygen to embryo and remove many wastes
  67. What is the Biogenetic Law and who came up with it?
    Ontogeny recapitulates (summarizes) phylogeny; Haeckel
  68. What is the Principle of Recapitulation?
    Successive stages of individual development (ontogeny) correspond to successive adult ancestors in the line of evolutionary descent (phylogeny).
  69. What was the Principle of Recapitulation used for?
    • To explain the observed order of ontogenetic events.
    • To explain features in ontogeny that were transiet (i.e. tail and gill puches in humans)
  70. What is the updated version of the Biogenetic Law?
    General to specific morphology.
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BIOL432 Early Development
2011-09-15 03:44:51
BIOL432 Early Development

BIOL432 Early Development
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