Embryology

Front 1

where fertilization usually occurs

Back 1

ampulla

Front 2

outer cell layer of blastocyst

Back 2

trophoblast

Front 3

inner cell mass of blastocyst

Back 3

embryoblast

Front 4

attachment to endometrial epithelium occurs when?

Back 4

end of week 1

Front 5

trophoblast differentiates when?
and into what?

Back 5

after implantation (end of week 1)
syncytiotrophoblast- outer invade cell wall
cytotrophoblast- inner

Front 6

HCG is what? what cells produce it?

Back 6

Human Chorionic Gonadotrophin
produced by syncytiotrophoblast

Front 7

where is hypoblast?
when does it form?

Back 7

on surface of embryoblast facing blastocyst
end of week 1

Front 8

what is the bilaminar germ disk? when does it appear?

Back 8

epiblast and hypoblast
end of week 1 beginning of week 2

Front 9

in what cell layer does the amniotic cavity develop?

Back 9

epiblast

Front 10

cavities above and below bilaminar germ disk?

Back 10

amniotic cavity above epiblast
exocoelomic cavity (primary yolk sac) below the hypoblast

Front 11

cells lining the primary yolk sac produce layer of loose CT called...

Back 11

the extraembryonic mesoderm

Front 12

extraembryonic mesoderm surrounds what?

Back 12

yolk sac, the amnion and the bilaminar disc

Front 13

extraembryonic coelom forms from vesicles in mesoderm, separating extraembryonic mesoderm into what two layers?

Back 13

extraembryonic somatic mesoderm
extraembryonic splanchnic mesoderm

in week2

Front 14

extraembryonic coelom is renamed....

Back 14

chorionic cavity

Front 15

growth of what pinches off the primary yolk sac?

Back 15

the chorionic cavity
creating the 2ndary (definitive) yolk sac

Front 16

GI tract derived most directly from what cavity developed at the end of the 2nd week?

Back 16

secondary yolk sac

Front 17

primitive streak originates where? and when?

Back 17

at caudal (posterior end) of the bilaminar disc
week 3

Front 18

epiblast layer defines what aspect of disk? (allowing L/R sides to be determined)

Back 18

dorsal

Front 19

primitive node appears where relative to primative streak?

Back 19

develops at the anterior end of primative streak

Front 20

primative node and streak both move toward...

Back 20

the "head" of the disc

Front 21

depression in primative streak and node

Back 21

develops primative groove and pit respectively

Front 22

what is gastrulation? when does it occur?

Back 22

migration of cells from the epiblast through the primative groove and pit into area underneath (ventral)

Front 23

embryonic endoderm forms from cells from where? what layer does it replace?

Back 23

cells from epiblast
replace hypoblast to form..

Front 24

intraembryonic mesoderm forms from what kind of cells? migrating between what layers?

Back 24

epiblast cells migrate between epiblast and newly formed embryonic endoderm

Front 25

layer of epiblast cells remaining after gastrulation is called

Back 25

the embryonic ectoderm

Front 26

trilaminar embryonic disk appears in what week? what distinguishes the 3 layers?

Back 26

3rd week
3 definitive germ layers
ectoderm, mesoderm, endoderm

Front 27

notocordal process formed by...

Back 27

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

Front 28

what induces neural plate formation?

Back 28

notocord induces ectoderm to thicken and form

Front 29

neurulation comprises:

Back 29

formation of the neural plate, folding of plate into the neural folds, and closure of folds to form neural tube

Front 30

neuralation commences when? when does it end

Back 30

begins in 3rd week, completed by end of 4th week

Front 31

neural crest cells formed from what layer?

Back 31

surface ectoderm projections that form during neurulation

Front 32

folate is important for what major part of embryonic development

Back 32

neurulation, formation of the neural tube

Front 33

during neurulation mesoderm is doing what?

Back 33

differentiating into paraxial, intermedaite and lateral plate columns

Front 34

urogenital system arises from what part of mesoderm?

Back 34

intermediate mesoderm

Front 35

what mesoderm column is imporatnt in body folding?

Back 35

lateral mesoderm

Front 36

which part of mesoderm developes into somites?

Back 36

paraxial mesoderm

Front 37

in what direction does somite differentiation occur?

Back 37

craniocaudal direction

Front 38

sclerotome

Back 38

portion of each somite that will give rise to bone and cartilage

Front 39

dermomyotome

Back 39

will give rise to skeletal muscle and connective tissue

Front 40

how does ectoderm "zip up" following neurulation

Back 40

folds meet in neck region, proceed toward cranial and caudal ends with anterior neuropore closing before the posterior neuropore (late in the 4th week)

Front 41

gut tube results from what kind of folding?

Back 41

lateral folding, produced by amniotic cavity growth

Front 42

lateral plate mesoderm sub-layer lining the inside of the future body wall

Back 42

somatic or parietal mesoderm

Front 43

lateral plate mesoderm sub-layer lining the outside of the yolk sac

Back 43

splanchnic or visceral mesoderm

Front 44

intraembryonic coelom is produced by what?

Back 44

the meeting of lateral folds in the anterior midline forms the internal body cavity (first called...)