Which one of the following is a characteristic of myogenic heart?

Options

A. Impulse is generated by special muscular tissue that develops within the heart
B. There are special conducting nerve fibre for spreading the impulse
C. It will stop beating immediately when heart is detached from the body
D. Impulse of heart beat is generated by nervous system but spread by muscles

Answer

To determine the characteristic of a myogenic heart, we can analyze the given options based on the definition and features of myogenic hearts.

### Step-by-Step Solution:

1. **Understanding Myogenic Heart**:
- A myogenic heart is one where the heartbeat is initiated by the heart muscle itself rather than by external nervous stimulation. In humans and many other vertebrates, the sinoatrial (SA) node, located in the right atrium, acts as the pacemaker.

2. **Evaluating the Options**:
- **Option 1**: "Impulse is generated by the special muscular tissue that developed within the heart."
- This statement is correct. The SA node is a specialized muscular tissue that generates the electrical impulses necessary for heartbeats.

- **Option 2**: "There are special conducting nerve fibers for spreading the impulse."
- This statement is incorrect for a myogenic heart. Myogenic hearts do not rely on nerve fibers for impulse generation; they generate impulses intrinsically.

- **Option 3**: "It will stop beating immediately when the heart is detached from the body."
- This statement is also incorrect. A myogenic heart can continue to beat for a short time after being detached due to the autonomous nature of the SA node.

- **Option 4**: "Impulse of the heartbeat is generated by the nervous system but spread by muscles."
- This statement is incorrect. In a myogenic heart, the impulse is generated by the heart muscle itself, not by the nervous system.

3. **Conclusion**:
- Based on the analysis, the correct characteristic of a myogenic heart is represented in **Option 1**: "Impulse is generated by the special muscular tissue that developed within the heart."

### Final Answer:
The characteristic of a myogenic heart is that the impulse is generated by the special muscular tissue that developed within the heart (Option 1).

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