Which valves prevent backflow into the ventricles during ventricular systole?

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Multiple Choice

Which valves prevent backflow into the ventricles during ventricular systole?

During ventricular systole the ventricles contract to eject blood into the aorta and pulmonary trunk. The valves that close to prevent any blood from flowing backward into the atria are the atrioventricular valves; they seal off the pathway between the atria and ventricles as the ventricles pressurize. The semilunar valves, on the other hand, are open during systole to allow ejection into the arterial trunk, and they prevent backflow from the arteries into the ventricles by closing during diastole when arterial pressure can push blood backward. So, there isn’t backflow into the ventricles to prevent during systole—the semilunar valves do that job only when the heart is relaxing (diastole). The key idea is: AV valves handle backflow into the atria during ventricular contraction, while semilunar valves prevent backflow from the arteries into the ventricles during diastole.

During ventricular systole the ventricles contract to eject blood into the aorta and pulmonary trunk. The valves that close to prevent any blood from flowing backward into the atria are the atrioventricular valves; they seal off the pathway between the atria and ventricles as the ventricles pressurize. The semilunar valves, on the other hand, are open during systole to allow ejection into the arterial trunk, and they prevent backflow from the arteries into the ventricles by closing during diastole when arterial pressure can push blood backward.

So, there isn’t backflow into the ventricles to prevent during systole—the semilunar valves do that job only when the heart is relaxing (diastole). The key idea is: AV valves handle backflow into the atria during ventricular contraction, while semilunar valves prevent backflow from the arteries into the ventricles during diastole.

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