Which layer of the heart is responsible for differential thickness of different chambers?

Options

A. Epicardium
B. Myocardium
C. Endocardium
D. Pericardium

Answer

To determine which layer of the heart is responsible for the differential thickness of different chambers, we can analyze the structure of the heart wall, which consists of three main layers: epicardium, myocardium, and endocardium.

### Step-by-Step Solution:

1. **Identify the Layers of the Heart**:
- The heart wall is composed of three layers:
- Epicardium (outer layer)
- Myocardium (middle layer)
- Endocardium (inner layer)

2. **Understand the Function of Each Layer**:
- **Epicardium**: This is the thin, transparent outer layer of the heart wall, made up of delicate connective tissue. It does not contribute significantly to the thickness of the heart.
- **Endocardium**: This is the inner layer that provides a smooth lining for the heart chambers. It is also thin and does not contribute to the thickness of the heart wall.
- **Myocardium**: This is the muscular middle layer of the heart wall. It contains cardiac muscle tissue and is responsible for the pumping action of the heart.

3. **Analyze the Thickness of the Chambers**:
- The myocardium varies in thickness in different chambers of the heart. For example, the left ventricle has a thicker myocardium compared to the right ventricle because it needs to pump blood to the entire body, while the right ventricle only pumps blood to the lungs.

4. **Conclusion**:
- The layer responsible for the differential thickness of different chambers of the heart is the **myocardium**. It is the muscular layer that provides the necessary strength for the heart's pumping action.

### Final Answer:
The layer of the heart responsible for the differential thickness of different chambers is the **myocardium**.

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