Comparative Heart Development Flashcards
what is the lub sound?
closing of the AV valve
what is the dub sound?
closing of the semilunar valves
where does the cranial vena cava take blood from?
blood from the head, neck and forelimbs
where does the caudal vena cava take blood from?
blood from the thorax and caudalward (rest of body)
what cervical spine levels did the phrenic nerve form from?
C5-7
“C7, 6, 5 keeps the diaphragm alive”
what does the conus cordis form?
distal outflow tracts for both right and left ventricles
what forms with the beginning of separation of ventricles?
interventricular sulcus
what are the 3 stages of septation in the heart?
1) atrioventricular septation
2) atrial separation
3) ventricular separation
+ division of the aortic and pulmonary outflow
what are the steps of atrioventricular septation?
1) endocardial cushions develop between the atrium and the ventricle
2) endocardial cushions fuse in the craniocaudal axis
3) fusion divides atrioventricular canal into right and left parts
when do ventricles realign?
during cushion fusion
why might blood need to be bypassed from the right ventricle during development?
skips pathway to lung because blood doesn’t need to go to lungs
describe the atrial septation pathway
-septum primum grows from roof
-grows down toward endocardial cushions
-foramen primum forms shunt thereby bypassing the right ventricle
what is the fossa ovalis?
impression in wall between the right and left atria
describe ventricular septation
-muscular interventricular septum arises from floor of primitive ventricle
-does not fuse with the fused endocardial cushions, instead incomplete fushion leaves a gap –> the interventricular foramen
what are the 3 shunts that bypass the liver and lungs during fetal circulation?
1) foramen ovale
2) ductus arteriosus
3) ductus venosus
