cardiac cycle

Question 1

describe what happens during atrial systole

Answer 1

• atria contract
• ventricles relax
• there is higher pressure in the atria than in the ventricles
• atrioventricular valves open
• blood flows from atria to ventricles

Question 2

Explain how valves control the flow of blood through the heart

Answer 2

Valves prevent backflow of blood. They open when the pressure in front of the valve exceeds the pressure behind the valve and close when pressure behind the valve exceeds pressure in front of the valve

Question 3

describe what happens during ventricular systole

Answer 3

• ventricles contract
• atria relax
• there is higher pressure in the ventricles than atria
• atrioventricular valves close to prevent backflow
• semi lunar valves open
• blood flows from ventricles to ateries

Question 4

describe what happens during diastole

Answer 4

• atria relax so begin to fill with blood
• atrioventricular valves open
• ventricles relax so have a lower pressure so blood enters from atria
• arterial pressure is high
• semilunar valves close to prevent backflow