The Early Embryo Flashcards
What happens to the zygote as it moved along the oviduct?
It develops!
On what day does the blastocyst implant to the uterine wall?
8
What does the placenta do?
Links mother and baby whilst keeping their blood circulations separate.
Does the embryos size increase during early stages of development?
No
What role do the outside cells play?
Aid implantation to the uterine wall
What are the 2 cell populations that the ICM will give rise to?
Epiblast (primitive ectoderm) and hypoblast (primitive endoderm).
What are the 3 lineages that the epiblast will give rise to?
Endoderm, mesoderm, endoderm
What is ZGA?
The kickstart of gene expression in the 2 cell embryo
What might happen if the embryo does not start expressing its own genes at the 2 cell stage?
It won’t be at the blastocyst stage by the time it reaches the uterus and won’t be able to implant
What are the 3 models that describe how the inside and outside lineages are determined?
- Pre-patterning model
- Inside outside model
- Cell polarity model
What gene expression is increased in inside cells?
Oct4
Increased expression of what gene occurs in outside cells?
Cdx2
What effect does increased cdx2 expression have on oct4 expression?
It represses it
What 2 ways can a cell know if it is an inside or outside cell?
- It’s access to the outside environment
2. Only inside cells give activation to hippo signaling factor
