cardiac cycle

Question 1

describe what happens during cardiac diastole

Answer 1

• the heart is relaxed
• blood enters the atria, increasing pressure and pushing open the atrioventricular valves
• this allows blood to flow into the ventricles
• pressure in the heart is lower than in the arteries, so semilunar valves remain closed

Question 2

describe what happens during atrial systole

Answer 2

the atria contract, pushing any remaining blood into the ventricles

Question 3

describe what happens during ventricular systole

Answer 3

the ventricles contract, the pressure increases, closing the atrioventricular valves to prevent backflow, and opening the semilunar valves, blood flows into the arteries

Question 4

how do you calculate cardiac output?

Answer 4

cardiac output = heart rate x stroke volume