The second heart sound is produced

Options

A. 1)during ventricular systole by the closure of semilunar valves
B. 2)by the closure of atrioventricular valves during ventricular systole
C. 3)during diastole by the closure of semilunar valves
D. 4)by the closure of tricuspid and bicuspid valves during joint diastole.

Answer

To answer the question regarding the production of the second heart sound, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Heart Sounds**: The heart produces two main sounds during its cycle, commonly referred to as "lub" and "dub." The first sound (lub) is produced by the closure of the atrioventricular (AV) valves, while the second sound (dub) is produced by the closure of the semi-lunar valves.

2. **Identifying the Second Heart Sound**: The second heart sound (dub) occurs at the end of ventricular systole, which is the phase of the cardiac cycle when the ventricles contract to pump blood out of the heart.

3. **Closure of Semi-lunar Valves**: The semi-lunar valves consist of the aortic valve and the pulmonary valve. The closure of these valves is what produces the second heart sound.

4. **Analyzing the Options**:
- **Option 1**: During ventricular systole by the closure of semi-lunar valve. (This is correct)
- **Option 2**: By the closure of atrioventricular valve during ventricular systole. (This is incorrect; this produces the first sound)
- **Option 3**: During diastole by the closure of semi-lunar valve. (This is incorrect; the second sound occurs during systole)
- **Option 4**: By the closure of tricuspid and bicuspid valve during joint diastole. (This is incorrect; this also produces the first sound)

5. **Conclusion**: The correct answer is that the second heart sound is produced during ventricular systole by the closure of the semi-lunar valves.

### Final Answer:
The second heart sound is produced during ventricular systole by the closure of the semi-lunar valves (Option 1).

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