final chp 13 cardio Flashcards
when does the cardiovascular system develop?
3rd week
-grow rapidly for nutrition requirements
what are the four angioblasts?
- splanchnic mesoderm
- mesenchyme of the yolk sac
- mesenchyme of the umbilical cord
- mesoderm of the chorion
what are some of the location for the formation of blood cells?
yolk sac 4th week body and mesenchyme and blood vessel 5th week liver 6th week spleen, thymus and lymph 2-3 months bone marrow 4th month
during the 3rd week main blood vessels develop the paired longitudinal vessels become the?
dorsal aorta
anteriorly- aortic arches
posteriorly- heart primordia
what do the second set of longitudinal blood vessels become during the 3rd week?
vitelline and umbilical veins
what do the vitelline veins do?
returns blood from yolk sac
what do the umbilical veins do?
brings blood from the chorion (placenta)
what do the cardinal veins do?
returns blood from body
what are the two thin walled endothelial tubes, that are a continuation of the first aortic arches, and eventually fuses to form a single tube?
endocardial heart tubes
what give sthe heart its shape?
the bubus and ventricle grow faster then the rest of the heart
what starts at the lower end of the heart?
the atrium, the growth moves it to the upper portion
when does simple ebb and flow type of circulation begin?
22nd day
myogenic origin
when does the heart have a unidirectional blood flow with contractions of the heart tube?
28-30 days
what is the septum primum?
sickle-shaped crest roof of atrium
what is the ostium primum?
opening between septum primum and endocardial cushion