AEMCA Practice Exam

What event occurs in the heart during diastole?

1. Contraction of the ventricles

2. Filling of the chambers with blood

3. Closing of the heart valves

4. Electrical impulse generation

The correct answer is: Filling of the chambers with blood

During diastole, the heart undergoes a critical phase of relaxation and filling. This is the period when the heart chambers, particularly the atria and ventricles, fill with blood in preparation for the next contraction. As the heart muscles relax, the pressure within the chambers decreases, allowing blood to flow in from the veins. The atrioventricular valves open to permit the flow of blood into the ventricles, ensuring they are adequately filled before the next pumping action, which occurs during the subsequent contraction phase of the cardiac cycle. Understanding this process is essential because effective filling of the heart chambers is vital for maintaining adequate cardiac output and overall circulation. If this filling phase is compromised, it can lead to reduced blood flow and oxygen delivery to the body, which underscores the importance of diastole in the heart's operation. Other options, such as the contraction of the ventricles, closing of heart valves, or electrical impulse generation, occur during different phases of the cardiac cycle and do not describe the active event during diastole itself.