At the end of joint diastole ventricle is

Options

A. Completely filled by blood
B. Two third filled by blood
C. One third filled by blood
D. Completely empty

Answer

To solve the question "At the end of joint diastole, ventricle is?", we need to understand the phases of the cardiac cycle, particularly focusing on diastole and how the ventricles are filled with blood.

### Step-by-Step Solution:

1. **Understanding Joint Diastole**:
- Joint diastole refers to the phase in the cardiac cycle when both the atria and ventricles are relaxed and filling with blood. This phase allows the heart chambers to fill before the next contraction.

2. **Ventricular Filling**:
- During joint diastole, the ventricles receive blood from the atria. The filling of the ventricles occurs in two main parts: passive filling and active filling.

3. **Passive Filling**:
- Initially, blood flows passively from the atria into the ventricles due to the pressure gradient when the atrioventricular (AV) valves (mitral and tricuspid valves) are open. This accounts for a significant portion of the ventricular filling.

4. **Active Filling**:
- Towards the end of joint diastole, the atria contract (this is called atrial systole), pushing additional blood into the ventricles. This contraction helps to fill the ventricles more completely.

5. **Volume Assessment**:
- At the end of joint diastole, the ventricles are not completely filled; they are approximately two-thirds filled with blood. The remaining volume is filled during the atrial contraction.

6. **Conclusion**:
- Therefore, at the end of joint diastole, the correct answer is that the ventricles are "two-thirds filled by blood."

### Final Answer:
At the end of joint diastole, the ventricle is two-thirds filled by blood.

---