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 given statements are incorrect, let's analyze each statement one by one:

### Step 1: Analyze Statement 1
**Statement 1:** The second heart sound is DUB, which is associated with the closure of bicuspid and tricuspid valves.
**Analysis:** This statement is incorrect. The second heart sound (DUB) is actually associated with the closure of the semilunar valves, which are the aortic and pulmonary valves, not the bicuspid (mitral) and tricuspid valves.

### Step 2: Analyze Statement 2
**Statement 2:** The duration between consecutive second and first heart sound is 0.5 seconds in a cardiac cycle.
**Analysis:** This statement is also incorrect. The duration between the first heart sound (LUB) and the second heart sound (DUB) is approximately 0.8 seconds in a typical cardiac cycle, not 0.5 seconds.

### Step 3: Analyze Statement 3
**Statement 3:** The heartbeat of a human increases when the adrenaline hormone is injected into it.
**Analysis:** This statement is correct. Adrenaline (epinephrine) increases heart rate as part of the body's fight-or-flight response.

### Step 4: Analyze Statement 4
**Statement 4:** The atrial systole in a cardiac cycle increases the flow of blood into the respective ventricle by about 70%.
**Analysis:** This statement is also correct. During atrial systole, the contraction of the atria helps to push blood into the ventricles, contributing to about 70% of the ventricular filling.

### Conclusion
Now, let's summarize the analysis:
- Statement 1: Incorrect
- Statement 2: Incorrect
- Statement 3: Correct
- Statement 4: Correct

**Total Incorrect Statements:** 2

### Final Answer
There are **2 incorrect statements** among the four provided.

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