Lecture one Flashcards
what are the key mechanisms cells rearrange themselves by at gastrulation
invagination ingression involution epiboly intercalation convergent extension
what mechanisms are use in the sea urchin at gastrulation
invagination and ingression
what mechanisms are used by the xenopus at gastrulation
involution
gastrulation in chicks and mammals
what does the hypoblast arise from
originates from delaminating cells and cells migrating from posterior marginal zone; gives rise to extraembryonic membranes
what is the primitive streak/groove
furrow forming from the posterior marginal zone through ingression of epiblast cells into the blastocoel (mesoderm) or to replace hypoblast (endoderm)
what is hensens node
where the primitve groove closes at the anterior marking the onset of organogenesis
what does the hypoblast develop into
yolk sac
what does the epiblast develop into
amnion cavity and chorion
what are the 3 resuts of gastrulation
3 germ layers
formation of the archeteron
appearance of major body axis
the process of forming somite
primitive streak closes
invagination of neural plate
somite form with neuroectoderm and mesoderm
what are the three broad derivatives of the trunk mesoderm
lateral plate mesoderm
intermediate
notochord
what does the lateral plate mesoderm develop into
- somatic: lateral & ventral dermis. limb skeleton
- splanchnic: heart & blood vessels (vasculogenesis), extraembryonic membranes
what does the intermediate of the trunk mesoderm develop into
intermediate
- kidney
- gonads
what does the notochord develop into
signalling (NS induction, somite patterning)
core of vertebral discs
defines chordate phylum (lancet fish, tunicates, vertebrates)
what is the epiblast
upper or outer layer
