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
foramen primum
free edge of septum primum defines openeing
foramen primum is _____ opening
temporary
when does the foramen primum close
when septum primum fuses with endocardial cushions
a second opening forms in the septum primum (before foramen primum closes) called the
foramen (ostium) secundum; programmed cell death
septum secundum forms to ____ of septum primum and grows towards _____
right; grows towards endocardial cushions
free edge of septum secundum defines opening called
foramen ovale (gap at junction of with endocardial cushion)
septum secundum persists as
interatrial wall
septum primum perists in its position next to septum secundum with portion over foramen ovale becoming the
valve of the foramen ovale
separation of left and right atria establish ______
left and right atrioventricular orififces
development of what follows
right and left AV valves
how do the separate atria form
endocardial cuhsions grow toward each other and fuse
inflow end of primitive heart tube is the
sinus venosus
sinus venosus is composed of
equal sized left and right horns of sinus venosus
_______ between sinus venosus and primitive atrium
weide opening
sinus venosus recieves blood from
developing embryo/fetal body and umbilical vein
_____ horn loses importance and ____ horn dominates
left; right
opening of sinus venosus shifts to ___ side of heart tube (as atria are separating into r and l)
right
right horn maintained as
inflow area to right atrium
left horn becomes
smaller coronary sinus and great cardiac vein of heart
as development progresses, right horn of sinus venosus incorporated into
wall of right atrium
right horn of sinus venosus becomes
smooth wall of sinus venarum
primitive right atrium becomes
auricle with pectinate muscle
junction sinus venosus and primitive right atrium ecomes
crista terminalis
pulmonary veins develop as
independent outgrowths of left atrium
single vein grows out from left atrium and branches to
both lungs as they form
left atrium enlarges incorporating
proxmal part of single pulmonary vein past the point where it branches (single open to multiple openings)
common outflow arterial tube is the
truncus arteriosus
truncus arteriosus connnects _____ to major arteries
bulbus cordis
two opposing ridges appear in
truncus arteriosus and bulbus cordis
ridges grow in _____ from _____
180 degree spiral from proximal to distal
ridges grow toward ______ and ____
eachother; fuse into the aorticopullmonary or spiral septum
aorticopulmonary or spiral septum divides what
truncus arteriosus/bulbus cordis into aorta and pulmonary trunk
spiral nature of aorticopullmonary septum means
pulmonary trunk twists around aorta
spiral essential to
interconnnect pulmonary and systemic circuits
interventricular septum grows from
ventral part of primitive, common ventricle (apex of heart) toward endocardial cushions
since primitive ventricle is muscular
muscular portion of interventricular septum
opening defined by free edge is the
interventricular foramen
interventricular foramen eventually closed by
the thinner membranous portion of interventricular septum
derived from cells of
endocardial cushin, aorticopulmonary (spiral) septum and muscular interventricular septum
aortic and pulmonary valves arise from
3 swellings of mesenchyme deep to endothelium at origin of aorta and pulmonary trunk
________ cells migrate into developing and contribute to
formation of cardiac valves
swellings hollow out to form
cusps
valves are a fold of endothelial tissue with ______ core
CCT
left and right atrioventricular valves arise from
swellings of mesenchyme at junction of atria and ventricles where common atrioventricular canal was divided into left and right by endocardial cushions
cavitation of muscle beneath
(ventricle side) mesodermal swellings and remodeling of swellings
creates
cusp shape and placement
leaves behind chordae tendinae which are
remnants of cavitated muscle tissue replaced with collagenous connective tissue
some muscle not removed remains as
papillary muscles securing chordae tendinae to ventricular wall
left AV valve ____ cusps
2 cusps
right AV valve ___ cusps
3 cusps
