Lecture 24: Gastrulation Flashcards
gastrulation
formation of the endoderm, mesoderm, and ectoderm from epiblast and hypoblast, axes development also occurs at this time
ingression
movement of cells from the outside to the inside of the embryo, AKA epithelial to mesenchymal transformation
invagination
cells fold inward
involution
cells folding over each other
spreading/convergent extension
cells move into a narrow line, helps lengthen the tissue, move it forward, or form tubular structures, process occurs via cell surface lampellipodia
bilaminar disc
contains an epiblast and hypoblast layer, also has buccopharyngeal membrane and cloacal membrane
buccopharyngeal membrane
forms into mouth
cloacal membrane
forms into anus
gastrulation process
1.) cells from epiderm ingress through primitive streak to form the definitive endoderm 2.) ingresssing cells replace the hypoblast 3.) once suffice definitive endoderm cells have ingressed, the ingressing cells form the mesoderm 4.) mesodermal cells migrate via spreading convergent extension after leaving the primitive streak 5.) cells with different cranial/caudal positions who leave the primitive streaks have different fates
hyaluronic acid
prevents mesodermal cells from clumping together
morphogenesis
process by which tissue and organs form
ectoderm
skin and nervous system
mesoderm
muscle, bone, blood
endoderm
guts, lungs, liver, pancreas
differentiation
occurs at the level of CELLS (process by which cells take on their separate identity)
morphogenesis
occurs at the level of TISSUES (process the gives rise to the shape and form of tissue and organs)