Gastrulation Flashcards
What does the ectoderm give rise to?
Hair Skin CNS PNS Cornea
What does mesoderm give rise to?
Kidneys Gonads Bones Blood vessels Heart
What does endoderm give rise to?
1. Epithelial linings of: GI Bladder Res tract Auditory tubes 2. Organs: Stomach Colon Lungs Bladder
From where do cells migrate to the primative streak?
Epiblast
Describe process of gastrulation
- Invading cells displace hypoblast forming endoderm
- Cells between epiblast and endoderm form middle layer mesoderm
- What was epiblast becomes ectoderm
What does the establishment of the body axes depend on?
Site-specific gene expression patterns
What protein initaites and maintains the primative streak?
Nodal
member of TGF-Beta family
What is produced once primative streak is formed?
- Bone morphogenetic protein (BMP)
2. Fibroblast growth factor (FGF)
Which FGF in particular induces nodal?
FGF8
What is function of the primative node?
An organiser
Why does most activity occur on the left side?
Cilia pushing FGF8 to left to make gradient
When does the primative streak regress and what happens thereafter?
End of week 4 and embryo develops cephalocaudally
What is the definitive notochord?
Underlies neural tubes and serves as basis for axial skeleton
How is definitive notochord formed?
Cells migrate through primitive streak, intercalate in endoderm (notochordal plate), and finally detach from endoderm
What is fate mapping?
Cells of the developing mesoderm migrate and give rise to regions of mesoderm with distinct fates in terms of body plan
