cardiac cycle Flashcards
state the first stage of the cardiac cycle
atria fill with blood from the veins
what is relaxed at the first stage of the cycle
all chambers
what effect does the atria filling with blood have on the pressure
increases pressure and therefore blood trickles into ventricles and pushes open the atrioventricular valves
what does the pressure increasing in the atria do to the atrioventricular valves
pushes them open
what is the name of the atrioventricular valve on the right/left side of the heart
right= tricuspid valve
left= bicuspid valve
what does the walls of the atria do after atrioventricular valves are pushed open
contract (atrial systole)
why is there a short delay between contraction of atria and ventricles
to allow the full contraction of the atria (atrial systole)
what happens after the full contraction of the atria
ventricles relax (ventricular systole)
which way do the walls of the ventricles contract
from bottom up
what’s the effect of contracting the ventricles on pressure and volume
decreases volume, increases pressure
what’s the effect of ventricular systole
pushes shut the atrio-ventricular valves = prevents backflow
what’s the role of the valves
preventing backflow
what sound is produced from the shutting of the atrioventricular valves
lub
what is the pressure in the ventricles compared to the pressure in the arteries (pulmonary artery/aorta)
pressure in ventricles is higher
what happens to the semilunar valve when the pressure is greater in the ventricles than the arteries
pushes open the valves and forces blood out of the heart into the arteries
what happens to the pressure and semilunar valves when the ventricles relax
pressure falls and semilunar valves shut
what noise is produced when the semilunar valves shut
dub
