Gastrulation and Neurulation Flashcards
What is gastrulation?
Changing the bilaminar into the tri-laminar layers
What happens in week 3 of development?
A groove forms in the epiblast called the primitive streak with it ending with a primitive node at the centre
The anterior visceral endoderm of hypoblast defines the anterior side/ head
What function does the primitive pit give?
Gives the disc left and right
What occurs along the primitive streak and primitive node?
Epiblast cells start to differentiate and multiply and start to invade into the embryo
They then replace the hypoblast layer and turn it into the endoderm
They also invade outwards creating a third layer, the mesoderm
They also migrate anteriorly to from the notochord
Where does the notochord lie?
Beneath the epiblast
What occurs once the notochord has been formed?
The cells that lie anteriorly for the neural plate, made from columnar epithelium
At what day does a midline groove become apparent in the neural plate?
19
What happens in days 20-21?
Cells on neural plate thicken forming the neural fold and groove
What happens from day 22?
The edges of the neural tube close together and fuse
It is done this by actin filaments tightening and creating curvature
What are the two ends of the neural tube?
Rostral neuropore
Caudal neuropore
How long does it take for closure of the rostral neuropore?
25 days
How long does it take for closure of the caudal neuropore?
27 days
What happens if the rostral neuropore fails to close?
Anencephaly
What happens if the caudal neuropore fails to close?
Spina bifida
Where are neural crest cells found and what do they do?
They derive from the edges of the neural tube and undergo an epithelial to mesenchymal transition
