Embryology: Week 4-8

Week 4-8  

11 cards   |   Total Attempts: 183
  

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Cards In This Set

Front Back
Describe what happens to the neural tube in week 4.
It is converted from a flat disc to a cylinder which is curved at both ends.
How does the NT bend?
THe bending is brought about the by the early growth of somites.
What are somites and what do they develop into?
They are blocks of mesodermal tissue either side of the neural tube and they develop into muscle, dermis and the vertebral column.
Who is the gut tube formed?
By bending of the endoderm. leading to constriction of the embryo which constricts the yolk sac.
Why does a midgut herniation occur?
The gut tube grows at too fast a rate which cannot be contained by the embryo, which results in it being herniated between weeks 5-10.
When can organogenesis begin.
When the 3 germ layers are defined.
When does the heart begin development?
Week 3, it starts contraction about day 22 and it must function as it develops.
List 3 things which happen in week 5.
1. Development and differentiation of brain and facial prominences 2. Limb buds develop 3. Heart valves and septum develop
List 6 events of week 6.
1. Upper limb differentiation 2. Noticeable eyes due to retinal pirmentation 3. Spontaneous and reflex movement 4. Bone Ossification 5. Sex differentiation 6. Gland like lungs
List 2 events of week 7.
1. Further limb development 2. Roughly time of midgut herniation
List 3 events of week 8.
1. Digits seperated but webbed 2. Region of limbs differentiated 3. Purposeful movement