Which term describes the relaxation of the heart muscles when blood is flowing into the heart's chambers and the heart is getting ready to start another beat?

Which term describes the relaxation of the heart muscles when blood is flowing into the heart's chambers and the heart is getting ready to start another beat?

• A. Systole
• B. Isovolumetric Relaxation
• C. Atrial Systole
• D. Diastole

Answer: (D)

Diastole is the relaxation phase of the heartbeat when the ventricles are relaxed and fill with blood from the atria, preparing for the next beat. As the heart relaxes, the atrioventricular valves are open, allowing blood to flow into the chambers. The slight late filling that includes the atrial kick happens at the end of diastole, but the overall relaxation and filling process define diastole. Systole is the contraction phase, and isovolumetric relaxation is a brief subphase with all valves closed, so no filling occurs then. Therefore, the term that matches this description is diastole.

Diastole is the relaxation phase of the heartbeat when the ventricles are relaxed and fill with blood from the atria, preparing for the next beat. As the heart relaxes, the atrioventricular valves are open, allowing blood to flow into the chambers. The slight late filling that includes the atrial kick happens at the end of diastole, but the overall relaxation and filling process define diastole. Systole is the contraction phase, and isovolumetric relaxation is a brief subphase with all valves closed, so no filling occurs then. Therefore, the term that matches this description is diastole.