During diastole

Options

A. Blood enter lungs
B. Blood leaves the ventricle
C. Blood leaves the heart
D. Blood enter the heart

Answer

**Step-by-Step Solution:**

1. **Understanding Diastole**: Diastole refers to the phase of the cardiac cycle when the heart muscle relaxes. This allows the chambers of the heart to fill with blood.

2. **Atrial Diastole**: During atrial diastole, both the right and left atria are relaxed. Blood flows into the right atrium from the body through the superior and inferior vena cava, bringing deoxygenated blood. Simultaneously, oxygenated blood flows into the left atrium from the lungs via the pulmonary veins.

3. **Ventricular Diastole**: Following atrial diastole, the ventricles also enter diastole. During this phase, the blood that has filled the atria moves into the ventricles. The left ventricle receives oxygenated blood from the left atrium, while the right ventricle receives deoxygenated blood from the right atrium.

4. **Conclusion**: Throughout both atrial and ventricular diastole, blood is entering the heart. Therefore, the correct answer to the question "During diastole" is that blood enters the heart.

**Final Answer**: Blood enters the heart during diastole.

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