Read the following four statements (1-4)
(1 ) The second heart sound is DUB, which is associated with the closure of bicuspid and tricuspid valves .
(2) The duration between consecutive second and first heart sound is 0.5 second in a cardiac cycle .
(3) The heartbeat of a human increase when the adrenaline hormone in injected into it.
(4) The atrial systole in a cardiac cycle increase the flow of blood into the respective ventricle by about 70% .
How many of the above statements are incorrect ?

Options

A. Three
B. Four
C. Two
D. One

Answer

To determine how many of the statements are incorrect, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1**: "The second heart sound is DUB, which is associated with the closure of bicuspid and tricuspid valves."
- **Analysis**: The second heart sound (DUB) is actually associated with the closure of the semilunar valves (aortic and pulmonary valves), not the bicuspid (mitral) and tricuspid valves. The closure of the bicuspid and tricuspid valves is associated with the first heart sound (LUB).
- **Conclusion**: This statement is incorrect.

2. **Statement 2**: "The duration between consecutive second and first heart sound is 0.5 seconds in a cardiac cycle."
- **Analysis**: The duration between the first heart sound (LUB) and the second heart sound (DUB) is approximately 0.3 seconds, not 0.5 seconds. The total duration of a complete cardiac cycle is about 0.8 seconds.
- **Conclusion**: This statement is incorrect.

3. **Statement 3**: "The heartbeat of a human increases when the adrenaline hormone is injected into it."
- **Analysis**: Adrenaline (epinephrine) is known to increase heart rate, especially during stress or emergency situations (fight or flight response). This statement accurately reflects the physiological effect of adrenaline.
- **Conclusion**: This statement is correct.

4. **Statement 4**: "The atrial systole in a cardiac cycle increases the flow of blood into the respective ventricle by about 70%."
- **Analysis**: Atrial systole contributes to the filling of the ventricles, but it is responsible for about 20-30% of the ventricular filling. The majority of ventricular filling occurs passively during diastole. Therefore, stating that it increases the flow by 70% is incorrect.
- **Conclusion**: This statement is incorrect.

### Summary of Findings:
- **Incorrect Statements**: 1, 2, and 4 are incorrect.
- **Correct Statements**: 3 is correct.

### Final Answer:
Out of the four statements, **3 statements are incorrect**.

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