Assertion : The cardiac impulse is said to be myogenic.
Reasoning : The rate of formation and conduction of cardiac impulse can be changed by the action of nerves.

Options

A. If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
B. If both Assertion and Reason are true, but the Reason is not the correct explanation of the Assertion.
C. If Assertion is true, but Reason is false.
D. If both Assertion and Reason are false.

Answer

To solve the question regarding the assertion and reasoning about the cardiac impulse, we will break it down step by step.

### Step 1: Understand the Assertion
The assertion states that "The cardiac impulse is said to be myogenic."
- **Explanation**: Myogenic means that the impulse originates from muscle tissue rather than nerve tissue. In the heart, the cardiac impulse is generated by specialized muscle cells in the sinoatrial (SA) node, which is known as the natural pacemaker of the heart.

### Step 2: Validate the Assertion
- **True or False**: The assertion is true because the SA node generates electrical impulses that initiate heart contractions, and this process is indeed myogenic.

### Step 3: Understand the Reasoning
The reasoning states that "The rate of formation and conduction of cardiac impulse can be changed by the action of nerves."
- **Explanation**: While it is true that the autonomic nervous system can influence the heart rate (for example, the sympathetic nervous system can increase heart rate, while the parasympathetic nervous system can decrease it), the origin of the impulse itself remains myogenic.

### Step 4: Validate the Reasoning
- **True or False**: The reasoning is also true, but it does not correctly explain the assertion. The assertion is about the origin of the cardiac impulse being myogenic, while the reasoning discusses the modulation of heart rate by nerves.

### Step 5: Conclusion
- **Final Answer**: Both the assertion and reasoning are true, but the reasoning is not the correct explanation for the assertion.

### Summary of the Solution:
- Assertion: True (Cardiac impulse is myogenic)
- Reasoning: True (Nerves can influence heart rate)
- Conclusion: Both are true, but the reasoning does not explain the assertion.

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