Embryology Flashcards
what is a fertilised egg called?
zygote
what is a morula and when does it appear?
solid mass of cells from 4-6 days
what is a blastocyst and when does it appear?
a hollow ball of cells from 6-10 days
what are the two parts of a blastocyst?
inner cell mass and trophoblast
what is the baby’s blood replenished by?
the mothers blood
what are the mothers and baby’s circulations mixed by?
a thin barrier
what happens at 10-12 days?
the implanted trophoblast contains an embryo which has 2 cell layers
what are the two layers of the bilaminar embyro?
epiblast and hypoblast
what does the epiblast give rise to?
the embryonic ectoderm, mesoderm and endoderm
what does the hypoblast give rise to?
endoderm and extraembryonic mesoderm
what does the embryo develop during gastrulation?
an axis (to become bilaterally symmetrical) and the third embrionic cell layer
where does the mesoderm come from?
ectodermal cells which migrate through the primitive streak towards the hypoblast
what forms the endoderm?
an interaction between the mesoderm and the hypoblast
what forms the third layer of the embryo?
the mesodermal cells pushing through the primitive streak
what is organogenesis and when does it happen?
the major organs developing from basic germ cell layers and it happens at week 3-8
what is the neural tube?
the forerunner of the central nervous system
where does the neural crest come from?
the ectoderm but has characteristics of the mesenchyme
what is the neural crest also called?
the ectomesenchyme
what organs appear when the embryo folds around the yolk sac?
the heart liver and lungs
what are stem cells?
unspecialised cells that can develop into more specialised cells
what are totipotent cells?
inner cell mass
what are pluripotent cells?
cells in the 3 germ layers that are more restricted in potential
what does stem cell development involve?
genes and various signalling molecules
what are the 3 primary embryonic layers?
ectoderm, mesoderm and endoderm
