The amount of air remaining in the air passages and alveloi at the end of quiet respiration is

Options

A. tidal volume
B. residual volume
C. inspiratory reserve volume
D. functional residual capacity

Answer

To solve the question, "The amount of air remaining in the air passages and alveoli at the end of quiet respiration is," we need to understand the various terms related to lung volumes and capacities. Let’s break it down step by step.

### Step-by-Step Solution:

1. **Understand Tidal Volume (TV)**:
- Tidal Volume is the amount of air that is inhaled or exhaled during normal breathing. It does not account for the air left in the lungs after exhalation.
- **Conclusion**: Tidal Volume is not the answer.

2. **Understand Residual Volume (RV)**:
- Residual Volume is the amount of air that remains in the lungs after a forceful exhalation. This air cannot be expelled from the lungs and is not what we are looking for in this question.
- **Conclusion**: Residual Volume is not the answer.

3. **Understand Inspiratory Reserve Volume (IRV)**:
- Inspiratory Reserve Volume is the amount of air that can be forcefully inhaled after a normal inhalation. This volume is also not related to the air remaining after quiet respiration.
- **Conclusion**: Inspiratory Reserve Volume is not the answer.

4. **Understand Functional Residual Capacity (FRC)**:
- Functional Residual Capacity is the volume of air remaining in the lungs (including the air passages and alveoli) after a normal, quiet expiration. This is exactly what the question is asking for.
- **Conclusion**: Functional Residual Capacity is the correct answer.

5. **Final Answer**:
- The amount of air remaining in the air passages and alveoli at the end of quiet respiration is **Functional Residual Capacity (FRC)**.