19 - Gastrulation Flashcards
1
Q
what occurs at day 5 to the blastocyst?
A
differeciates into trophoblast and embryoblast
2
Q
which cells are pluripotent?
A
the inner cell mass cells are pluripotent
can dfferenciate into any cells
3
Q
what does the inner cell masss/embryoblast differecniate into at day 5?
A
- into 2 layers
- epiblast (top)
- hypoblast (bottom)
- together is bilaminar embry. disc
4
Q
What is the amniotic cavity?
A
- a cavity that forms between the epi and hypoblast
2 cavitys now, blastocyst cavity and amniotic cavity during implantation
5
Q
How is the Chorionic cavity formed?
A
- hypoblast cells move to cytotrophoblast cells
- form a extracoelemic membrane
- cells between the extracoleomic membrane and the cytoTB become the extra embryonic mesoderm
- cavity forms in extra embryonic mesoderm - Chorionic Cavity
- surrounds embryo
- gast begins
6
Q
when does gastrulation occur?
A
- 3rd week
7
Q
how does gastrulation begin?
A
- primitive streak forms in surface of epiblast cells at the CAUDAL end (tail)
- primitive node formed facing cranial end
8
Q
invagination?
A
- epiblast cells migrate toward primitive streak
- cells change their shape and detach from epiblast
9
Q
formation of the 3 germ layers?
A
ENDODERM
- cells that enter groove that displace hypoblast cells
MESODERM
- cells that do invaginate and lie between endo and ectoderm
ECTODERM
- epiblast cells that didn’t invaginate and remain
