American Board of Surgery Qualifying Exam (ABS QE) Practice Test

How is FVC defined in lung physiology?

1. The volume of air remaining in the lungs after forced expiration

2. The amount of air forcefully expired after a maximal inspiration

3. The total volume of breath taken in naturally

4. The maximum volume of air breathed in from FRC

The correct answer is: The amount of air forcefully expired after a maximal inspiration

Forced Vital Capacity (FVC) is defined as the amount of air that can be forcefully expired after a maximal inspiration. This measurement is an essential component of pulmonary function tests and provides valuable information about lung function. It reflects the strength and capacity of the lungs to expel air, making it a critical parameter in assessing conditions such as restrictive and obstructive lung diseases. To clarify further, FVC is specifically focused on the forceful expiration following a complete inhalation, which differentiates it from other lung volume measurements. For instance, the volume of air remaining in the lungs after forced expiration refers to Residual Volume, while the total volume of breath taken in naturally describes Tidal Volume. Additionally, the notion of the maximum volume of air breathed in from Functional Residual Capacity (FRC) does not align with the definition of FVC. Thus, the accurate definition reinforces the understanding of lung dynamics and its clinical relevance in respiratory health.