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

Options

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

Answer

To answer the question "Which layer of the heart is responsible for differential thickness of different chambers?", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Layers of the Heart**: The heart has three main layers: the epicardium, myocardium, and endocardium. Each layer has distinct functions and characteristics.

2. **Understand the Function of Each Layer**:
- **Epicardium**: This is the outer layer of the heart, primarily made up of connective tissue. Its main function is to provide protection to the heart.
- **Myocardium**: This is the middle layer and is composed of cardiac muscle tissue. It is responsible for the contraction of the heart and varies in thickness in different chambers.
- **Endocardium**: This is the innermost layer that lines the chambers of the heart and is involved in providing a smooth surface for blood flow.

3. **Focus on the Myocardium**: The myocardium is the layer that is responsible for the differential thickness of the heart chambers. For example, the left ventricle has a thicker myocardium compared to the right ventricle because it needs to generate more force to pump blood throughout the body.

4. **Eliminate Incorrect Options**:
- The epicardium does not contribute to the thickness of the chambers.
- The endocardium is not responsible for the thickness but rather lines the chambers.
- The pericardium is a protective sac surrounding the heart and does not influence the thickness of the heart walls.

5. **Conclusion**: Based on the functions and characteristics of the heart layers, the myocardium is the correct answer as it is responsible for the differential thickness of the different chambers of the heart.

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

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