Heart

Question 1

1) Ventricles relax, atria contract

Answer 1

Ventricles are relaxed. Atria contract, decreasing volume and increasing the pressure. This pushes blood into ventricles via atrioventricular valve. Slight increase in ventricular pressure and volume as the ventricles receive the ejected blood from the atria

Question 2

2) ventricles contract, atria relax

Answer 2

Atria relax. Ventricles contract increasing the pressure. This forces the atrioventricular valves to shut but opens the semi lunar valve into pulmonary artery and aorta

Question 3

3) ventricles relax, atria relax

Answer 3

Both relax. Semilunar valves close because of high pressure in the pulmonary artery and aorta. Atria fills increasing pressure. Ventricles relax and atrioventricular valve opens up again