Filling of ventricles with the blood takes place during:

Options

A. Ventricular diastole only
B. Atrial systole only
C. Ventricular and atrial systole
D. Joint diastole and atrial systole

Answer

To solve the question "Filling of ventricles with the blood takes place during:", we will analyze the phases of the cardiac cycle and determine when the ventricles fill with blood.

### Step-by-Step Solution:

1. **Understand the Cardiac Cycle**:
The cardiac cycle consists of two main phases: diastole and systole. Diastole is when the heart muscles relax, and systole is when they contract.

**Hint**: Remember that diastole means relaxation, while systole means contraction.

2. **Identify the Phases of Filling**:
- **Joint Diastole**: During this phase, both the atria and ventricles are relaxed. Blood flows from the veins into the atria and then into the ventricles.
- **Atrial Systole**: In this phase, the atria contract, pushing additional blood into the ventricles.

**Hint**: Think about how blood moves from areas of higher pressure to lower pressure; during relaxation, blood fills the ventricles.

3. **Consider Other Phases**:
- **Ventricular Systole**: This is when the ventricles contract to pump blood out of the heart. During this phase, the ventricles are not filling with blood; instead, they are expelling it.
- **Joint Diastole and Atrial Systole**: Both phases contribute to the filling of the ventricles.

**Hint**: Focus on which phases involve the ventricles receiving blood rather than expelling it.

4. **Conclusion**:
The filling of the ventricles occurs during both the joint diastole and atrial systole phases. Therefore, the correct answer is that the ventricles fill with blood during these phases.

**Final Answer**: The filling of ventricles with blood takes place during **joint diastole and atrial systole**.

### Final Answer:
**Option D: Joint diastole and atrial systole**