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14 Cards in this Set
- Front
- Back
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When does embryonic folding begin? When is it completed |
Week 3 Week 4 |
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What is responsible for the thickening of the ectoderm in week 3? |
Notochord formation It continues to expand as notochord develops and regresses |
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Which germ layer is the nervous system derived from |
Ectoderm |
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Function of the notochord |
Signalling centre for ectoderm Restricts ectoderm from forming varied derivative tissues - only nervous tissue No hair/ nails etc. |
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Days 18- 21 |
Neural plate - Butterfly developnent Neural groove formed - future folding point Primitive streak disappears @ day 21 |
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Cranial and Caudal Folding |
Notochord induces changes in ectoderm -》 formation of neural plate Somites differentiating in mesoderm Both put on pressure Embryo expands laterally, then ventally |
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Cranio- caudal folding |
Head fold - Forebrain extends cranially - fast froth of neural plate - 180° fold - Primordial heart and oropharyngeal membrane move ventrally - Endoderm of yolk sac is encorporated in forest Tail Fold - Growth of neural tube - caudal eminence covers cloacal membrane - 180° fold - Endooderm incorporated in hindgut - connecting stalk lies ventrally |
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Lateral Folding |
Produced by rapid expansion of neural plate and somites Primordium of ventrolateral walls fold to ventral midline Formation of cylindrical embryo Endoderm incorporated in gut Formation of Intra embryonic coelum Midgut remains in broad contact w/ yolk sac until week 6 - @ wk 6 Gut is finally formed - neck of yolk sac is reduced in vitelline duct Tube within a tube |
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Embryonic folding gone wrong |
Anterior Abdomjnal wall defects Omphalocele - herniated bowel - Bowel is covered in membranous sac Gastrioshisus - Bowel protrudes on the surface - usually to the right of umbilicus Anterior thoracic wall defects Ectopia cordis - heart protruding Pentalogy of Cattrall - midline abdominal wall defect - anterior diaphragmatic hernia - cleft sternum - pericardial defects - intracranial defects |
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AAW Defects |
Anterior Abdomjnal wall defectsOmphalocele - herniated bowel - Bowel is covered in membranous sacGastrioshisus - Bowel protrudes on the surface - usually to the right of umbilicus |
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Omphalocele |
Omphalocele - herniated bowel - Bowel is covered in membranous sac |
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Pentalogy of Cattrall |
Pentalogy of Cattrall - midline abdominal wall defect - anterior diaphragmatic hernia - cleft sternum - pericardial defects - intracranial defects |
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Gastrioshisus |
Gastrioshisus - Bowel protrudes on the surface - usually to the right of Anterior thoracic wall defects |
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Ectopia cordis |
Protruding Heart |
