Week 7 - Human Dev Flashcards
What are the key events of fertilization?
- Sperm-Zona Pellucida Binding
- The Acrosome Reaction
- Penetration of the Zona Pellucida
- Fusion of plasma membranes
- Sperm enters egg cytoplasm
morula - def/time
solid, 16 cell mass 3-4 days post fertilization within zona pellucida
blastocyst - def/time
inner cell mass + trophoblast + cavity - 5 days , eventually implants
formation of the bilaminar disc def/time
formation of epiblast and hypoblast from the ICM, making an amniotic cavity - 7-10 days
gastrulation
week 3 - formation of the ectoderm, mesoderm, and endoderm
neurulation
week 3 - notochord induces the formation of the central nervous system (CNS) by signaling the ectoderm germ layer to fold down the neural plate
Which cells in the different stages of embryogenesis are totipotent? Pluripotent?
ICM - totipotent
bilaminar/gastrulation - pluripotent
How does gastrulation occur?
Nodal signals the primitive streak, which is the first polarizing event. Beta-catenin is needed for cell adhesion. Epithelial to mesenchymal transition (EMT) is triggered by FGF8
3 germ layer resulting from gastrulation
ecto, meso, endo
a trophoblast is part of the _____ and gives rise to the _____
blastocyst, placenta
are the primitive streak and neural tube the same thing?
no
first cleavage event
24 hours
division of somatic (body) cells
mitosis
length of cleavage phase
1-3 days
the blastomeres of the morula are ______potent
toti
