heart action Flashcards
1
Q
heart pumps blood when…
A
its muscles contract
2
Q
contraction… (3)
A
squeezes blood out of chamber
semi-lunar valves open
atrioventricular valves closed to prevent blood from flowing back to atria
3
Q
relaxation (3)
A
atria fill up with blood from veins
semi-lunar valves closed
atrioventricular valves open due to pressure of blood from atria
4
Q
atria ____ and ______ at the same time
A
contract, relax
5
Q
ventricles _____ and ______ at the same time
A
contract, relax
6
Q
contraction 2 phases
A
- atria contract and force blood into the ventricles
2. the ventricles contract and force blood out of the arteries
7
Q
cardiac cycle
A
the changes that occur during one heart beat
