Gastrulation Flashcards
Gastrulation
differentiates
archenteron created
body axis created
triploblastic (3germ layers)
Ectoderm
outer layer, will become skin cells
part of neurolation, becomes neural cells after induction from neural chord
mesoderm
middle layer,
skeleton
muscles
made of fold between ecto and endo derm
endoderm
internmost layer
gastrointestinal tract
big tube in the middle
Archenteron
blastoceol becomes this after the blastopore begins to form and depression collapses into blastoceol
1st opening becomes blastopore
blastopore
first opening in archenteron
endoderm cells flow over dorsal lip inside to line it
dorsal lip
opening into blastopore/archenteron
animal pole cells flow over it inside
formation of blastopore
blastopore forms on dorsal side
dorsal lip forms at this opening
animal pole cells roll over and into
Involution
blastopore forms circle
expand endo and mesoderm internally
arche grows asn blastocoel shrinks
yolk cells internalizes
blastopore plugged with yolk
RESULT
3 germ layers
archenteron
blastopore (with dorsal lip)
involution definition
cell movement in which expanding outer layer turns inward and spreads over surface
Convergent extension
two distinct lines of cells join to combine their length
extends archenteron
human gatrulation
4 extraembryonic membranes including amnion
Primitive streat
blastopore equivalent
epiblast cells move to midline, detach, and move in