Early mammalian embryology Flashcards
What is the yolk and cleavage type?
Rotational holoblastic cleavage, isolecithal yolk
Define a morula
a solid ball of cells resulting from division of a fertilized ovum, and from which a blastula is formed.
In what portion of fertilization canal does the zygote undergo its first division?
In the ampula
What two types of cells appear at the 16 cell stage?
Trophoblast cells and ICM cells (Embryonic Stem Cells)
A note about polarity.
A variety of factors may need to be on one side in order to repress some factors and what not.
Define asymmetry
an uneven distribution of organelles, molecules, or functions within individual cells of the same type
Define polarity
a situation where the asymmetrically distributed entities have an invariable, noninterchangeable and irreplaceable position in all cells of the same type
Can the direction that a cell is divided cause assymetry?
yes. Just keep this in mind
Polarization of factors leads to…
…different determinants in progeny cells
Go over the videos! there will be questions
You can’t tell me what to do. But its good advice..
What are the first types of cells to flow through the primitive groove?
endoderm cells
What types of cells does the endoderm coming through the primitive groove push out?
hypoblast
What is the second kind of cell that comes through the primitive groove?
mesoderm
What is the fetal portion of the placenta called?
chorion
What is the maternal portion of the placenta called?
decidual cells
