Grade seven, my teacher's a pain. She didn't even explain the 'sets', we just know what valves are in general. So.. which set of valves closes when the ventricles contract? Relax? Thank you so much!***10 POINTS***
There are two types of valves in the heart: the atrio-ventricular (AV) valves and the semi-lunar valves. There are two AV valves: the tricuspid between the right atrium and the right ventricle, and the mitral (also called bicuspid) between the left atrium and the left ventricle. There are also two semi-lunar valves: the pulmonic semi-lunar, between the right ventricle and the pulmonary trunk (artery) and the aortic semi-lunar, between the left ventricle and the aorta. During diastole (the relaxation phase), the AV valves are open and the semi-lunar valves are closed, so the ventricles can fill with blood. During systole (the contraction phase), the AV valves close and the semi-lunar valves open so the blood can be pumped around the body.
Atrioventricular valves close when it relaxes and the lunar valves close when it contracts
