Biology: The Cardiac Cycle

Question 1

What happens during atrial systole?

Answer 1

-ventricles relax, atria contract -volume decrease, pressure increase -atrioventricular valves fully open -blood pushed into ventricles

Question 2

What happens during ventricular systole?

Answer 2

-ventricles contract, atria relax -volume decrease, pressure increase -atrioventricular valves close -semilunar valves forced open -blood pumped through arteries

Question 3

What occurs during diastole of the cardiac cycle?

Answer 3

-atria and ventricles relax -arterial pressure lower than veins -semilunar valves close -blood enters atria from veins -atria pressure exceeds ventricular pressure -atrioventricular valves open slightly -blood into ventricles passively -cycle restarts

Question 4

What is one heartbeat equal to?

Answer 4

time it takes for one complete cardiac cycle

Question 5

What equation is used to calculate cardiac output?

Answer 5

cardiac output (cm3min-1) = stroke volume (cm3/beat) x heart rate (bpm)