x exam 2 cardiovascular development Flashcards
cardiogenic area or plate is made from
cranial end of early embryonic disc; from mesoderm
cardiogenic area is forms _______ as body folding occurs
left and right primitive heart tubes
head and tail folds give embryo
C shape
lateral body folds give embryo
sides
as body folding occurs, right and left endocardial tubes do what
fuse
folding pushes the entire cardiogenic area ________ in the region of the caudal neck and cranial thorax
ventral body surface
what are the 3 layers of the primitve heart tube
endocardium (lines inside spaces_
myocardium (cardiac muscle tissue)
epicardium or visceral pericardium (surrounds outside)
space or pocket in mesoderm ventral to primitive heart is the
pericardial cavity
mesoderm sheet
dorsal mesocardium supsends primitive heart tube in pericardial cavity
when do blood vessels form
at the same time the primitive heart tube is forming and elongate to establish circulation
blood vessesl begin as
blood islands
vasculogenesis
blood islands organize into vessels
where do the blood vessels form
in mesoderm of embryo and in splanchnic mesoderm of yolk sac
angiogenesis
established vessels sprout toward a target
vessels attach to
either end of heart tube
inflow vessels are
venous (right and left sinus venosus)
outflow vessels are
arterial ends (right and left atria)
once vessels are established, what can begin
heart beat and circulation begins
bulboventricle is composed of
ventricle and bulbus cordis
truncus arteriosus is
outflow arteries (right and left aortic arches)
rapid, differential growth of heart tube forces it to loop or bend to bring precursors of definitive heart chambers to approximate final positions causing
displacing the primitive ventricle ventrally
what happens to dorsal mesocardium
degenerates
what happens to bulboventricle
enlarges, sinus venosus shifts right (inflow to right atrium)
what happens to common atrium
enlarges and shifts dorsally
what regions enlarge and what regions stay narrow
region of primitive atrium and primitive ventricle enlarge while connecting area stays narrow
what is the common, constricted region at junction between primitive atrium and bulboventricle
atrioventricular canal
primitive atrium
single chamber, enlarges to left and right
artioventricular canal partitions
seprate left and right atrioventricular canals
two masses (dorsal and ventral) of mesoderm form known as
endocardial cushions
dorsal and ventral endocardial cushions do what
grow toward eachother and fuse
separate
left and right atrioventricular canals
separation of common atrium takes _____
2 septa (primary and secondary)
septum primum grows from
wall about the middle of common primitive atrium to endocardial cushion