Cardiovascular Embryology Flashcards
what is the advantage of developing the cardiovascular system early?
diffusion can only transfer nutrients and oxygen so far, the CV system allows it to grow beyond those short distances
what is the cardiogenic plate?
splanchnic mesoderm situated anterior to the embryo, moves ventrally as head process grows
site of first heart development with bilateral vessel formation
what fuses to form the future tubular heart?
endocardial tubes
What are the 5 primitive heart regions?
truncus arteriosus bulbus cordis ventricle atrium sinus venosus
truncus arteriosus
output region of heart
becomes ascending aorta and pulmonary trunk
bulbus cordis
becomes right ventricle
ventricle
becomes left ventricle
atrium
expands to become left and right auricles
sinus venosus
paired region where veins drain
left becomes coronary sinus
right becomes part of right atrium wall
what partitions the common AV opening?
endocardial cushions
foramen ovale
open septum in embryo that allows blood to flow from right atrium (higher pressure) to left
what happens if the truncus arteriosus isn’t partitioned in a spiral pattern?
the pulmonary trunk would be attached to the left ventricle and the aorta to the right which would be fatal
ventral and dorsal aortae
paired in embryo, connected by up to 6 aortic arches, each situated in a pharyngeal arch
dorsal aortae form the descending aorta
ventral aortae form the brachiocephalic trunk
what does the third aortic arch become?
the carotid arteries
what do the left and right fourth aortic arches become?
left becomes the arch of the aorta
right becomes right subclavian artery
what do the sixth aortic arches become?
pulmonary arteries
left distal arch becomes ductus arteriosus
ductus arteriosus
shuts blood from pulmonary trunk to aorta
abruptly constricts at birth, shifts flow to lungs
then becomes ligamentum arteriosum
vitelline veins
drain yolk sac into embryonic sinus venosus
form liver sinusoids and portal vein as liver develops and surrounds veins
umbilical veins
drain allantois into embryonic sinus venosus
contribute to liver sinusoids
create ductus venosus to shunt blood from liver until born
cardinal veins
drain the embryo into sinus venosus
which way does venous return shift in embryonic development?
to the right and the right sinus venosus become part of the right atrium
lymph node and vessel formation
begin as lymph sacs and vessels outgrow from sacs
nodes made by mesodermal invaginations
what happens to the shunts at birth?
ductus venosus slowly closes and allows flow to liver
ductus arteriosus constricts rapidly
foramen ovale closes rapidly as pressure equalizes between atria
