Cardiac embryology and congenital heart disease 1 Flashcards
Early cardiogenesis
male and female gametes fuse –> ____
fertilization
Early cardiogenesis
Unicellular zygote goes through a _____ resulting in ___ –> morula
series of cleave
increased number of cells
Early cardiogenesis
Morula transforms into a ___
blastocyst
early cardiogenesis process
1) male/female gamete fuse –> fertilization
2) unicellular zygote undergoes many cleavages –> morula
3) morula transform into a blastocyst
3 components of blastocyst
1) outer cell mass = trophoblast
2) inner cell mast = embryoblast
3) central cavity = blastocyst cavity
what is outer cell mass in blastocyst called
trophoblast
what is inner cell mass in blastocyst called
embryoblast
2 layers of embryoblast
external = epiblast
internal = hypoblast
what do the 2 layers of embryoblast form?
flat disc = embryonic disc
where are the precardiac cells located in blastocyst stage?
located in epiblast on either side of primitive streak
what happens to epiblast cells in blastocyst stage
epiblast cells invaginate down thru prim streak
–> intraembryonic mesoderm
what do epiblast cells become after migrating through prim treak
intraembryonic mesoderm
how many layers in gastrula
what are the layers called
3 layers
1) external = ectoderm
2) middle = mesoderm
3) internal = endoderm
where are precardiac cells in gastrula
precardiac cells in mesoderm
what happens to precardiac cells in gastrula
precardiac cells migrate cephalically (toward head)
when does heart begin developing in embryo?
day 16
where are pre-cardiac cells on day 16
in the cardiogenic area near cranial end
derived from mesodermal cells
what is cardiogenic area derived from
mesoderm
what happens to precardiac cells in cardiogenic area
on day 19
migrate so now ventral to forebrain and foregut
coalesce to form 2 endocardial tubes
when do precardiac cells in cardiogenic area begin to form 2 endocardial tubes
day 19
what happens after heart tube forms on day 19
heart tubes become lined with endothelial cell
splanchnic mesoderm surrounds heart tube
what surrounds heart tubes on day 19
splanchnic mesoderm
what happens by day 21-22
tubes fuse together due to cephalic and lateral folding of embryo –> primitive hear ttube
when does heart begin to beat
DAY 22
WHAT HAPPENS AFTER PRIMITIVE heart tube formed?
pre-loop
loop
post-loop with septation
when does pre-loop stage form?
day 22
what happens in preloop stage on day 22
AV sulcus becomes the intraventricular septum
primitive ventricle = trabeculated portion of LV
proximal portion of bulbus cordis = trabeculated portion of RV
blood flow
what creates the primitive ventricle
when happens?
day 22
comes from trabeculated portion of LV
what is the proximal portion of Bulbus Cordis
trabeculated portion of RV
what is the primordium of the trabeculated portion of RV also correspond to
proximal Bulbus cordis
when does blood flow begin
day 22
what happens to inner and outer layers of hear ttube
inner layer = endothelial lining –> endocardium
outer layer = mesoderm (epimyocardium) –> myocardium and epicardium
what is in between the inner and outer layer of heart tube
cardiac jelly (important in looping and septation)
what happens in looping stage during day 23-25
cardiac tube grows longitudinally at faster rate than rest of embryo
heart loops to right of embryo (D-loop)
what direct does heart loop?
to the right of embryo (D-loop)
how do primitive atria rotate during looping?
rotate posteriorly behind the RV and LV
how does axis of AV canal change with looping?
initially cephalic to caudal
–> becomes posterior to anterior
what happens in early post-loop stage
day 26-28
ventricles and atria now aligned
SEPTATION BEGINS
ventricular septum visible as outpouching
when does septation begin?
day 26-28
post-loop
what is anatomic correlate of bulbis cordis
trabeulated portion of RV
what is anatomic correlate of primitive ventricle
trabeculated portion of LV
what is anatomic correlate of conus
infundibula (outflow tract) of both ventricles
what is anatomic correlate of primtiive atria
left and right atrial appendages
what is anatomic correlate of truncus
aortic and pulm valves
aoscending aorta
pulm trunk
how does blood flow begin?
day 25
1) blood enter heart tube THROUGH SINUS VENOSUS VIA 3 SETS OF VEINS
1) umbilical vein (brings O2 blood) and disappears after birth
2) vitelline vein (brings nutrients from yolk sac)
3) cardinal vein (drains waste)
what is sinus venosus
where blood flow initially enters heart tube thru 3 veins
what is fxn of umbilical vein
drains blood from placenta thru sinus venosus
what is fxn of vitelline vein
drains blood from yolk sac thru sinus venosus
what is fxn of cardinal vein
drains blood from embryo thru sinus venosus
how do systemic veins develop
1) sinus venosus communicate with primitive atria via SA orifice
2) right and left sinus venous valve prevent flow reversal into sinus venosus w/ atrial contraction
what are components of right sinus venous valve
1) eustachion valve
2) IVC
3) thebsian vlave (guards coronary sinus)
what happens to left sinus venous valve
absorbed into atrial septum
what is anatomic correlate of right umbilical vein
disappears
what is anatomic correlate of left umbilical vein
distal –> ductus venosus (disappear after birth)
what is anatomic correlate of right vitelline vein
distal –> superior mesenteric artery
proximal –> suprahepatic IVC
(contribute to hepatic sinusoids)
what is anatomic correlate of left vitelline vein
contribute to hepatic sinusoids
what is anatomic correlate of right cardinal vein
SVC
brachiocephalic vein
inominate veins
what is anatomic correlate of left cardinal vein
ligament of Marshall
what is anatomic correlate of left sinus horn skip
distal –> ligament of Marshall
proximal –> coronary sinus
what is anatomic correlate of right sinus horn skip
absorbed into RA
how do pulm veins develop
part of splanchnic plexus –> pulm venous plexus –> pulm veins
how does common pulm vein develop
endothelail projection from LA connects pulm venous plexus
how does right and left pulm veins develop
lumen forms and common vein branches
when does atrial and ventricular septation occur
days 28-42
when does great artery form
days 35-56
great artery formation
septation of conus
1) in early post-loop stage, 4 masses on inside wall of conus moving inward
- -> dextrodorsal and sinstroventral conal crests
2) conal crests (moving down) fuse with ventricular septum (moving up) caudally
great artery formation
what are the 4 masses on inside wall of conus in septation of conus
dextrodorsal and sinistroventral conal crests
great artery formation
septation of truncus
1) mass in truncus
dextrosuperior and sinistroinferior truncal swelling
great artery formation
septation of truncus
what does right intercalated swelling become
noncoronary aortic cusp
great artery formation
septation of truncus
what does left intercalated swelling become
anteiror pulm cusp
great artery formation
spiraling of septation
forms in spiral
aorticopulm septum originates as extracardiac septum in aortic sac and separates aorta and pulm
superioventral conal crest continuous with sinistroinferior truncal swelling
dextrodorsal CC continuous with dextrosuperior truncal swelling
a
a
a
a
view of pulmonary artery
at great artery level
pulm artery is posterior and to left
aorta anterior and to right
view of pulmonary valve
at semiunar valve level
pulm valve is anterior and to left
aorta valve posterior to right
view of pulmonary infundibulum
at infundibular level
pulm infundibulum is anterior and to right of aortic infudnibulum
aortic infundibulum is now posterior to left
where do ascending and descending aorta come from
ascending aorta = aortic sac
descending aorta = left dorsal
what is anatomic correlate of 1st aortic arch
1st to disappear
maxillary and external carotid arteries
what is anatomic correlate of 2nd aortic arch
disappears
dorsal –> stapedial artery
what is anatomic correlate of 3rd aortic arch
carotid arteries
what is anatomic correlate of 4th aortic arch
right –> right brachiocephalic/right subclavian
left –> transverse aortic arch
what is anatomic correlate of 5th aortic arch
disappears
what is anatomic correlate of 6th aortic arch
prox, right –> prox right pulm artery
prox, left –> prox left pulm artery
distal, left –> ductus arteriosus