Which is incorrect with respect to regulation of cardiac activity :-

Options

A. Neural centre in medulla oblongata can mederate the cardiac function.
B. Parasympathetic nerves can increase the heart rate.
C. Sympathetic nerves can increase the strength of ventricular contraction.
D. Adrenal medullary hormones can also increase the cardiac output.

Answer

To determine which statement is incorrect with respect to the regulation of cardiac activity, let's analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Cardiac Activity Regulation**:
- Cardiac activity refers to the functioning of the heart, including heart rate and the strength of heart contractions.

2. **Evaluating Option 1**:
- **Statement**: "Neural center in the medulla oblongata can moderate the cardiac function."
- **Analysis**: The medulla oblongata is indeed a part of the brain that regulates autonomic functions, including heart rate. This statement is correct.

3. **Evaluating Option 2**:
- **Statement**: "Parasympathetic nerves can increase the heart rate."
- **Analysis**: The parasympathetic nervous system primarily acts to decrease heart rate. It is the sympathetic nervous system that increases heart rate. Therefore, this statement is incorrect.

4. **Evaluating Option 3**:
- **Statement**: "Sympathetic nerves can increase the strength of ventricular contraction."
- **Analysis**: The sympathetic nervous system does indeed increase the strength of ventricular contractions through the release of norepinephrine. This statement is correct.

5. **Evaluating Option 4**:
- **Statement**: "Adrenal medullary hormones can also increase the cardiac output."
- **Analysis**: The adrenal medulla releases hormones such as epinephrine and norepinephrine, which increase heart rate and stroke volume, thus increasing cardiac output. This statement is correct.

6. **Conclusion**:
- The only incorrect statement regarding the regulation of cardiac activity is **Option 2**: "Parasympathetic nerves can increase the heart rate."

### Final Answer:
The incorrect statement with respect to the regulation of cardiac activity is **Option 2**.

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