Embryology II

  1. Describe the process of neurulation.
    Cells invaginate through primitive pit and migrate towards buccopharyngeal membrane.
  2. What do notochrodal cell migrating forward forming a shild shape overlying structure give rise do?
  3. What does neuroectoderm give rise to?
    CNS and retina
  4. How does the neural tube form?
    Neural folds come together in midline over neural groove and fuse. Neuropore then zips up cranially and caudally.
  5. What does the neuropore communicate with?
    amnion cavity
  6. As neural folds differentiate into as they approach midline, differentiate, and detach laterally?
    neural crest cells
  7. What does the neural crest give rise to?
    • 1) Melanocytes
    • 2) Cartilage of bones in head from pharyngeal arches
    • 3) C cells of thyroid
    • 4) Aorticopulmonary septum
    • 5) Odontoblasts
    • 6) Adrenal Medulla
    • 7) Sensory and Motor Ganglia
    • 8) Schwann Cells
  8. What does the mangle layer of the spinal cord form from?
    Neuroepithelial cells that differentiate into neuroblasts
  9. What does the marginal layer of the spinal cord come from?
    Neuroblasts that differentiate into neurons and processes that extend into marginal layer
  10. What forms the ventricular layer of the spinal cord?
    Neuropithelial cells that do not differentiate
  11. What divides the mantle zone of the spinal cord into two latyers? What does this separate?
    • Sulcus limitans (Alar and Basal plate)
    • Alar = sensory
    • Basao = motor
    • Separates snesory and motor functions
  12. What layers in spinal cord are between white matter? Grey matter?
    • White - Marginal layer
    • Grey - Mantle layer
  13. What forms the wall of the thrird ventricle in the brain?
    Thalamus and hypothalamus
  14. Describe the flow of CSF.
    CSF is produces in lateral ventricle (choroid plexus) --> third ventricle --> fourth ventricle --> subarachnoid space --> reabsorbed through acahnoid villi
  15. What are the three primary vesicles the nerual tube dilates into?
    • Forebrain (proscencesphalon)
    • Midbrain (mesencephalon)
    • Hindbrain (rhombencephalon)
  16. What does the forebrain (prosencesphalon) give rise to?
    Telencephalon and Diencephalon
  17. What does telencephalon give rise to?
    Cerebral hemispheres
  18. What does diencephalon give rise to?
    Thalamus, hypothalamus
  19. What is the lateral wall of the third ventricle?
    Thalamus (dienchepalon)
  20. What dilation gives rise to midbrain?
  21. What dilation gives rise to pons and cerebellum?
  22. What dilation gives rise to medulla?
  23. What is the arrangement of the alar and basal plate in the floor of the 4th ventricle ?
    • Alar is lateral to basal
    • (Remember - alar is sensory and basal is motor)
  24. What does neurectoderm give rise to?
    • 1) CNS, retina, CN II
    • 2) Neurohypophysis
    • 3) Astrocytes, Oligodendrocytes
  25. What does the musculoskeletal system derive from mainly?
  26. What does proliferation of mesoderm near the notochord produce?
    • Paraxial mesoderm.
    • The remaining mesoderm is called lateral plate.
  27. What is between lateral plate and paraxial mesoderm?
    Intermediate mesoderm
  28. What does paraxial mesoderm form?
  29. What three regions does each somite have?
    • Sclerotome
    • Dermatome
    • Myotome
  30. What are less well organized regions of paraxial mesoderm cranially called?
  31. What is a sclerotome made of?
    Medial and ventral cells that migrate away and head toward notochord that becomes bone and cartilage of vertebral column.
  32. How many sclerotomes make up a vertebral body?
    • 2
    • Caudal and cranial portion of different sclerotomes fuse to form v. bodies.
  33. What does the remnant of the notochord form?
    Nucleus pulposus in intervertebral disk
  34. What germ layer do the bones of the face form from?
    Neural crest forms sphenoid bone, squamos portion of temporal bone, frontal, madible, etc.
  35. What does the rest of the cranial vault form from?
    Paraxial mesoderm
  36. What does a dermatome form?
    Dermis of skin
  37. What does a myotome form?
    muscles of the region and retain segmental innervation
  38. What are some clinical signs of spina bifida?
    • Tuft of hair covering lesion
    • Increased AFB and AchEsterase
  39. What happens when the neural tube fails to close caudally?
    • Spina bifida (can be spina bifida occulta - no fusion of vertebra)
    • Spina bifida meningocele (with meninges protruding)
    • Spina bifida meningomyelocele (with spinal cord and meninges)
  40. What can meningomyelocele lead to?
    Arnold Chiaria malformation
  41. What is Rachiscisis?
    failure of spinal cord to form
  42. What happens when the neuropore fails to close cranially?
  43. What causes clinical presentation of anencephaly?
    • Exposes brain to amniotic fluid which destroys brain
    • Increased amnion fluid
    • Increased AFB
  44. What vies rise to the intrinsic muscles of the back?
  45. What does hypomere give rise to?
    muscle with thoracic, lateral and medial abdominal wall (muscles of trunk), some of hypomere forms limb muscles
  46. What vies rise to limb bones?
    Parietal mesoderm
  47. What sends messages into underlying mesenchyme for limb differentiation?
    Ectodermal ridge
  48. What are the first bones of the limb to develop?
    Forearm, then hands, them humerus
  49. Where did parietal mesoderm come from?
    lateral plate mesoderm
  50. What forms the digits of the hand? What does a failure of this process cause?
    • Apoptosis (programmed cell death)
    • Syndactyly
  51. What is it called when there is a complete abscence of limbs? Partial?
    • Complete - amelia
    • Partial - melomelia
    • (thalidomide caused this)
  52. What does parietal lateral plate mesoderm give rise to?
    serous lining of peritoneal, pericardial, and pleural membranes
  53. What does visceral lateral plate mesoderm give rise to?
    cardiac and smooth muscle
  54. Describe the formation of the skeletal system.
    • Skeletal system is ALL from mesoderm
    • Sclerotome, Somite = bones of axial skeleton, cranial vault
    • Somatic layer of lateral plate mesoderm = bones of shoulder, pelvic girdle, and limbs
    • Neural crest = bones of face
  55. * The posterior neuropore provides a communication between what two spaces?
    The developing neural tube and the amnion
  56. * Cells of the adrenal medulla are derived from what?
    neural crest cells
  57. * The vertebrae are derived from segmental _______.
  58. * What part of the brain's ventricular system is derived from the diencephalon?
    third ventricle
  59. * The membrane lining the abdominal cavity is derived from what division of mesoderm?
    lateral plate
  60. * The sulcus limitans divides the developing central nervous system into what two major functional area?
    sensory and motor
Card Set
Embryology II
Embryology II