3rd & 4th weeks of Development M1S1

  1. Gastrulation is
    Process forming three germ layers ectoderm, mesoderm and endoderm
  2. Gastrulation has what three main steps
    • (1) formation of the primitive streak on the surface of the epiblast
    • (2) formation of the three germ layers
    • (3) formation of the notochord
  3. Formation of the germ layers begins by
    Epiblast cells migrate to the primitive streak, detach from the epiblast and slip under . Image Upload 1
  4. Notochord cells are considered to be what germ layer
  5. The inward movement of the epiblast is called invagination and is regulated by
    FGF (fibroblast growth factor)
  6. What eventually becomes the umbilical cord and then bladder
  7. Formation of the Notochord (mesoderm)
    Epiblasts move cranially towards the prechordal plate in the primitive pit. These cells form the notochord under the epiblast (3rd Week)
  8. Neurulation
    • A cavity is formed on the surface of the ectoderm eventually becoming completely consumed
    • Remnants of ectoderm left behind become neural creat cells
    • Image Upload 2
  9. BMP-4 has what effect on development
    Causes ectoderm to form epidermis and mesoderm to form the lateral plate and intermediate mesoderm
  10. What inactivates BMP-4
    Secretion of Noggin, Chordin
  11. Neural inducers (Noggin) cause what to develop
    Forebrain and midbrain development
  12. High levels, and Low levels of BMP cause what to form
    • High levels induce Epidermis formation
    • Low levels induce Neural crest formation
  13. Inhibition of BMP causes
    Neural plate induction (eventual neural tube)
  14. Closure of the cranial neuropore occurs at day
    25-26, whereas closure of the caudal neuropore occurs at day 27-28Image Upload 3
  15. Neurulation is completed when
    The neuropores close
  16. Lens placode invaginates during 5th week to form
    The lens of the eyes
  17. Otic vesicles will develop into structures for
    Hearing and equilibrium
  18. What arises from the ectoderm
    • 1) Central nervous system
    • 2) Peripheral nervous system
    • 3) Sensory epithelium of ear, eye and nose
    • 4) Epidermis of the skin including hair, nails and mammary glands
    • 5) The anterior portion of the Pituitary gland
    • 6) Enamal of teeth
    • 7) Derivatives of Neural crest cells
  19. Mesodermal Germ Layer by the 17th day, close at the midline forming
    • a) Paraxial mesoderm
    • b) Lateral plate mesoderm
    • c) Intermediate mesodermImage Upload 4
  20. By 8th week,the intraembryonic cavity will give rise to the
    Peritoneal, pleural and pericardial cavities.
  21. Thr lateral plate seperates into what layers
    • Parietal (somatic) forms lateral and ventral body walls
    • Visceral (splanchnic) forms wall of gut
  22. The myotome (paraxial mesoderm) of the somite will differentiate
    Into muscles of the body
  23. The Sclerotome of the somite (paraxial mesoderm) will differentiate into
    Vertebrae, skull, and ribs.
  24. The outer layer of somatic cells (paraxial mesoderm) will form the dermatome which will differentiate into
    The dermis of the skin
  25. Intermediate mesoderm will form
    Kidneys and gonads
  26. The Mesoderm forms
    • 1) C.T., cartilage and bones (except in the head and neck region)
    • 2) Striated, smooth and cardiac muscles
    • 3) Blood and lymph vessels, blood cells, and heart
    • 4) Kidneys
    • 5) Gonads and ducts
    • 6) Cortex of adrenal gland
    • 7) Spleen
    • 8) Serous membranes lining the body cavities
  27. The Endoderm forms
    • 1) Epithelial lining of the gastrointestinal tract
    • 2) Epithelial lining of the respiratory tract
    • 3) Parenchyma of the tonsils, thyroid and parathyroid glands, thymus, liver and pancreas
    • 4) Epithelial lining of the urinary bladder and most of the urethra
    • 5) Epithelial lining of the tympanic cavity and auditory tube
  28. During the formation of the notocord, mesoderm is everywhere but
    The Oropharyngeal (mouth) and cloacal (anus) membranes
  29. Which grows first, the head or the tail
    Head (cephalocaudally)
  30. The buccopharyngeal membrane is where what forms
    The mouth
  31. The Gi tract is derived from what layer
  32. The Central nervous system begins to develop when, and appears as what structure
    It appears at the 3rd week as the neural plate
  33. During what weeks is the embryo most seceptible to malformation
    Weeks 3-8
  34. A functional disturbance like mental retardation is most likely to occur during what time of development
    At the 8th week on to birth
  35. The heart fuses from one tube and starts beating when
    Day 21-22
  36. What is the growth factor triggering the growth of blood vessels and other vascular epithelium
    veg-1 (Thats why you eat your veggies!)
  37. What is angiogenesis
    New vessels arising from existing vessels
  38. What is vasculogenesis
    Vessels arising from blood islands
  39. What forms the oral cavity
  40. Each myotome and dermatome retains its
    Innervation from its segment of origination no matter where they migrate
  41. Somites can be used by doctors to determine
    How far along the embryo has developed (time wise)
  42. Sacrococcygeal teratoma is
    (Tumor in the sacro coccygeal area) a tumor that arises from remnants of the primitive streak which normally degenerates and disappears
  43. Sirenomelia
    • Image Upload 5
    • Loss of mesoderm in the lumbar sacral region due to the malformaion of the lower limbs
  44. When does the notochord begin to appear
    3rd week
  45. By the end of the third week the neural folds begin to raise and join where
    5th Somite
  46. Neural Tube defect of failure to close in cranial region
    AnencephalyImage Upload 6
  47. Gastroschisis
    • Image Upload 7
    • Newborn infant with undeveloped anterior abdominal wall
  48. The CNS is derived soley of what cells
    Neural Tube
  49. The PNS is derived of soley what cells
    Nueral crest cells
  50. The cloacal membrane (ectoderm and endoderm) ruptures on week, forming
    7 to form an opening of the anus.
  51. The oropharygeal membrane (composed of ectoderm and endoderm) ruptures in what week to form what
    Week 4 to form an opening of the foregut that communicates with the amniotic fluid.
  52. Microglia is made from
    Monocytes in the bone marrow
  53. Neuroblasts and glialblasts
    • Pre neurons
    • Pre glial cells
  54. Schwann cells are dervived from
    Neural Crest cells
  55. The mantle forms what in the spinal cord
    Dorsal sensory horn
  56. Alar plate is in the pre spinal cord where
    Dorsal end
  57. The basal plate in the prespinal cord is located
  58. SHH is released from what, to induce what
    Notochord to induce the ventral side formation
  59. Nerve fibers from the CNS don't become myelinated till when
    The first year of postnatal life
  60. What are the five sections of the neural tube from top to bottom
    • Telencephalon
    • Diencephalon
    • Mesencephalon
    • Metencephalon
    • Myelencephalon
  61. What does the telencephalon end up as
    Cerebral hemispheres
  62. What does the Diencephalon end up as
    Thalamus, Optic cup, Pituitary gland, Hypothalamus, pineal gland
  63. What does the mesencephalon end up forming
    The aquaduct of the brain
  64. What does the metencephalon end up forming
    Pons and Cerebellum
  65. What does the Myelencephalon end up forming
    The medulla
  66. What is unique about the Pyramid of medulla
    This is where the crossing over of the nerves from one hemisphere to the other takes place
  67. The colliculus is derived from
    Alar plate
  68. The hippocampus controls what functions
    Smell and long term memory
  69. The superior colliculus receives info from
    The eyes
  70. The inferior colliculus receives info from
    The ears
  71. The pineal gland is derived from
  72. Rathke's pouch, what comes from
    Pituitary gland
  73. Pharyngeal hypophusis is when
    A small portion of Ranthke's pouch perists in the roof of the pharyx
  74. Foramen of monro is
    A channel that connects the third ventricle with the lateral ventriclesImage Upload 8
  75. The olfactory bulbs are dervived from
  76. The sympathetic nervous system originates from
    Neural crest
  77. What cavity fills the telencephalon and the Diencephalon
  78. The mesencephalon has what cavity in it
  79. What cavity fills the Metencephalon and the Myelencephalon spaces
  80. Where is regeneration of the nerves possible and where is it not
    It happens in the PNS not in the CNS
  81. What are the three stages of regeneration
    Chromatolysis, Anterograde, Regeneration
  82. What happens in Chromatolyisis
    The amount of Nissl bodies is decreased
  83. What is the importance of schwann cells in regeneration
    They recruit macrophages to clear the way for a new axon to be made, and create a canal for budding axons to travel
Card Set
3rd & 4th weeks of Development M1S1