B8-031 Embryogenesis Flashcards
gastrulation begins with the formation of the
primitive streak
formation of trilaminar disc from epiblast occurs in week […]
3
layers formed during gastrulation [3]
endoderm
mesoderm
ectoderm
forms the extraembryonic endoderm and mesoderm
hypoblast
[…] cells are among the first to ingress from the primitive streak
pre-notochordal cells
acts with the primitive nodes as a second signaling regions in the head region
anterior visceral endoderm
expresses genes essential for head formation
inhibits the formation of the primitive streak in the head
anterior visceral endoderm
AVE
the anterior/cranial end of the embryo is established [before/after] gastrulation
before
dorsalizing molecules [4]
chordin
goosecoid
noggin
follistatin
dosalizing molecules dorsalize the cranial mesoderm to form [3]
head structures
notochord
paraxial mesoderm
antagonizes the dorsalizers
ventralizes mesoderm to form intermediate and lateral plate mesoderm
BMP 4
dorsalizes mesoderm in middle and caudal embryo to form paraxial mesoderm somites
brachyury T
what causes sirenomelia?
absence of Brachyury T
results in shortening of axis and fusion of limb buds
notochord forms ventral to
neural plate
notochord arises from mesoderm and induces the overlying ectoderm to form […]
neural plate
(notochord secrete the dorsalizing molecule to induce the ectoderm)
notochord and primitive streak [do/do not] overlap
do not
FGF8 establishes expression of nodal on the left, but then […] represses left-sideness genes on RIGHT
SHH
(results in right handedness)
abnormalities in cilia proteins lead to […] defects
laterality
(cilia set up directional fluid flow in the primitive node that moves the signaling molecules in specific patterns)
situs inversus and primary ciliary dyskinesia are due to defects in
cilia proteins
overexpression of […] results in conjoined twin phenotype
goosecoid
when is the embryo most sensitive to teratogenic insult
week 3
merged forebrain occurring due to high doses of alcohol consumption
holoprosencephaly
failure of eye fields to separate properly
synopthalmia
de novo formation of the endothelial tubes from precursor cells
vasculogenesis
sprouting of endothelial lined vascular tubes off existing vessels
angiogenesis
blood vessels form from […] mesoderm
LPM
unbalanced blood supply between twins in shared placenta
results in a net flow from one twin to the other
twin-twin transfusion syndrome
in twin-twin transfusion syndrome, the […] twin will present with hypovolemia and oligohydramnios
donor
in twin-twin transfusion syndrome, the […] twin will present with hypervolemia and polyhydramnios
recipient
congenital vascular malformation that is:
common
often occurs in craniofacial regions
may disappear over time
capillary hemangiomas
congenital vascular malformation that is:
less common
gets larger and darker over time
skin thickens
port-wine stains
defects of ventral body wall [4]
ectopia cordis
gastroschisis
cloacal exstrophy
bladder exstrophy
defects of ventral body wall are caused by
failure to close after lateral folding
the […] layer of the bilaminar germ disc contributes to cells that invaginate during gastrulation
epiblast
the […] consists of multinucleated cells
syncytiotrophoblast
the […] consists of small cuboidal cells
hypoblast
differentiate from the trophoblast [2]
syncytiotrophoblast
cytotrophoblast
the inner cell mass hallows to form the […] cavity
blastocyst
gastrulation starts with the formation of the [..] on the surface of the epiblast
primitive streak
dorsalized ectoderm that forms the neural tube
neural plate
notochord induces overlying […] to form
neural plate
the […] is at the cranial end of the primitive streak
primitive node
the primitive streak first extends […]
cranially
(those cells form the primitive node)
forms the non-invaginated epiblast
ectoderm
fusion of lower limbs and vertebral abnormalities
sirenomelia
transposition of the viscera in the thorax/abdomen
situs inversus
defects of cilia on node cells leads to […] defects
laterality
mesoderm is ventralized by
BMP4
nodal is expressed on the embryonic […] side
left
head genes are expressed in the
anterior visceral endoderm
responsible for dorsalization of the cranial mesoderm
chordin
lateral folding promotes formation of [4]
cardiac tube
gut tube
body cavities
ventral body wall
initial site of hematopoiesis during prenatal development
extraembryonic blood islands
hemangioblasts are derived from what germ layer?
mesoderm
hemangioblasts form [2]
hematopoietic stem cells
angioblasts
blood islands arise during the process of
vasculogenesis
epidermis is derived from
ectoderm
foregut lining is derived from
endoderm
dermis of the back is derived from
paraxial mesoderm
heart is derived from
splanchnic lateral plate mesoderm
urogenital system arises from
intermediate mesoderm
the embryonic period encompasses weeks […] of development
3-8
