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44 Cards in this Set

  • Front
  • Back
where fertilization usually occurs
outer cell layer of blastocyst
inner cell mass of blastocyst
attachment to endometrial epithelium occurs when?
end of week 1
trophoblast differentiates when?
and into what?
after implantation (end of week 1)
syncytiotrophoblast- outer invade cell wall
cytotrophoblast- inner
HCG is what? what cells produce it?
Human Chorionic Gonadotrophin
produced by syncytiotrophoblast
where is hypoblast?
when does it form?
on surface of embryoblast facing blastocyst
end of week 1
what is the bilaminar germ disk? when does it appear?
epiblast and hypoblast
end of week 1 beginning of week 2
in what cell layer does the amniotic cavity develop?
cavities above and below bilaminar germ disk?
amniotic cavity above epiblast
exocoelomic cavity (primary yolk sac) below the hypoblast
cells lining the primary yolk sac produce layer of loose CT called...
the extraembryonic mesoderm
extraembryonic mesoderm surrounds what?
yolk sac, the amnion and the bilaminar disc
extraembryonic coelom forms from vesicles in mesoderm, separating extraembryonic mesoderm into what two layers?
extraembryonic somatic mesoderm
extraembryonic splanchnic mesoderm

in week2
extraembryonic coelom is renamed....
chorionic cavity
growth of what pinches off the primary yolk sac?
the chorionic cavity
creating the 2ndary (definitive) yolk sac
GI tract derived most directly from what cavity developed at the end of the 2nd week?
secondary yolk sac
primitive streak originates where? and when?
at caudal (posterior end) of the bilaminar disc
week 3
epiblast layer defines what aspect of disk? (allowing L/R sides to be determined)
primitive node appears where relative to primative streak?
develops at the anterior end of primative streak
primative node and streak both move toward...
the "head" of the disc
depression in primative streak and node
develops primative groove and pit respectively
what is gastrulation? when does it occur?
migration of cells from the epiblast through the primative groove and pit into area underneath (ventral)
embryonic endoderm forms from cells from where? what layer does it replace?
cells from epiblast
replace hypoblast to form..
intraembryonic mesoderm forms from what kind of cells? migrating between what layers?
epiblast cells migrate between epiblast and newly formed embryonic endoderm
layer of epiblast cells remaining after gastrulation is called
the embryonic ectoderm
trilaminar embryonic disk appears in what week? what distinguishes the 3 layers?
3rd week
3 definitive germ layers
ectoderm, mesoderm, endoderm
notocordal process formed by...
subset of epiblast cells, migrating through primative pit in anterior direction in the midline of the mesodermal layer until it reaches and is stopped by orapharyngeal membrane
what induces neural plate formation?
notocord induces ectoderm to thicken and form
neurulation comprises:
formation of the neural plate, folding of plate into the neural folds, and closure of folds to form neural tube
neuralation commences when? when does it end
begins in 3rd week, completed by end of 4th week
neural crest cells formed from what layer?
surface ectoderm projections that form during neurulation
folate is important for what major part of embryonic development
neurulation, formation of the neural tube
during neurulation mesoderm is doing what?
differentiating into paraxial, intermedaite and lateral plate columns
urogenital system arises from what part of mesoderm?
intermediate mesoderm
what mesoderm column is imporatnt in body folding?
lateral mesoderm
which part of mesoderm developes into somites?
paraxial mesoderm
in what direction does somite differentiation occur?
craniocaudal direction
portion of each somite that will give rise to bone and cartilage
will give rise to skeletal muscle and connective tissue
how does ectoderm "zip up" following neurulation
folds meet in neck region, proceed toward cranial and caudal ends with anterior neuropore closing before the posterior neuropore (late in the 4th week)
gut tube results from what kind of folding?
lateral folding, produced by amniotic cavity growth
lateral plate mesoderm sub-layer lining the inside of the future body wall
somatic or parietal mesoderm
lateral plate mesoderm sub-layer lining the outside of the yolk sac
splanchnic or visceral mesoderm
intraembryonic coelom is produced by what?
the meeting of lateral folds in the anterior midline forms the internal body cavity (first called...)