ANATOMY
CHEST AND CARDIOVASCULAR
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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semilunar valves are closed
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both atria and ventricles are relaxed
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“dub” sound is made
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only ventricles are relaxed, atria are contracting
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Detailed explanation-1: -At the beginning of the cardiac cycle, both the atria and ventricles are relaxed (diastole). Blood is flowing into the right atrium from the superior and inferior venae cavae and the coronary sinus. Blood flows into the left atrium from the four pulmonary veins.
Detailed explanation-2: -Diastole begins with the closing of the aortic valve (or pulmonic) and ends with the closing of the mitral valve (or tricuspid). This period encompasses the ventricular relaxation and filling. Diastole represents when the blood vessels return blood to the heart in preparation for the next ventricular contraction.
Detailed explanation-3: -The heartbeat is caused by the heart muscles relaxing and contracting. During this cycle, the period of relaxation is called diastole and the period of contraction is called systole.