The forced expiratory volume (FEV1) measures:
A. how much air you can breathe out of your lungs after a deep inspiration.
B. the amount of air left in your lungs after you breathe it all out.
C. the amount of air you can forcibly exhale in one second.
D. how much force you can generate when breathing into a spirometer.
Answer (1)
FEV1 is a measure of lung function.
Option 1 describes Forced Vital Capacity (FVC).
Option 2 describes Residual Volume (RV).
FEV1 measures the amount of air you can forcibly exhale in one second.
Explanation
Understanding the Question The question asks us to identify the correct definition of forced expiratory volume (FEV1) from the given options. FEV1 is a measure used in respiratory medicine to assess lung function. Let's examine each option to determine the correct one.
Analyzing Option 1 Option 1: "how much air you can breathe out of your lungs after a deep inspiration." This describes the forced vital capacity (FVC), not FEV1. FVC is the total amount of air that can be exhaled forcefully after a deep breath.
Analyzing Option 2 Option 2: "the amount of air left in your lungs after you breathe it all out." This describes the residual volume (RV), which is the volume of air remaining in the lungs after a maximal exhalation.
Analyzing Option 3 Option 3: "the amount of air you can forcibly exhale in one second." This is the correct definition of FEV1. It measures the volume of air a person can exhale during the first second of a forced breath.
Analyzing Option 4 Option 4: "how much force you can generate when breathing into a spirometer." This is related to respiratory muscle strength, but FEV1 is a volume measurement, not a force measurement.
Conclusion Therefore, the correct answer is that FEV1 measures the amount of air you can forcibly exhale in one second.
Examples
FEV1 is used in diagnosing and monitoring respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD). For example, a doctor might use FEV1 measurements to assess the severity of asthma and to monitor the effectiveness of treatment. If a patient's FEV1 is significantly lower than normal, it could indicate that their airways are narrowed or blocked. This measurement helps healthcare professionals understand how well a patient's lungs are functioning and make informed decisions about their care.
