Which of the following is correct about the filling of the ventricles during the cardiac cycle?

• A. Ventricular filling is primarily passive, occurring during ventricular diastole.
• B. The majority of ventricular filling occurs during atrial systole.
• C. Ventricular filling is an active process requiring energy expenditure.
• D. Ventricular filling is completed during ventricular systole.

Answer: (A)

Verified step by step guidance

1. Understand the phases of the cardiac cycle: The cardiac cycle consists of systole (contraction) and diastole (relaxation) phases for both atria and ventricles.
2. Identify ventricular diastole: During ventricular diastole, the ventricles are relaxed, allowing blood to flow passively from the atria into the ventricles.
3. Recognize the role of atrial systole: Atrial systole occurs towards the end of ventricular diastole, where the atria contract to push additional blood into the ventricles, contributing to the final phase of ventricular filling.
4. Clarify the passive nature of ventricular filling: The majority of ventricular filling is passive, occurring during ventricular diastole, without requiring energy expenditure.
5. Distinguish between ventricular diastole and systole: Ventricular filling is completed before ventricular systole begins, as systole involves the contraction of ventricles to pump blood out of the heart.