Final answer:
The sample collected at the end of expiration is called the expiratory reserve volume (ERV), which is part of lung function assessment and can be measured through spirometry along with forced vital capacity (FVC) to diagnose and monitor lung conditions.
Step-by-step explanation:
When the sample is collected at the end of expiration, it is known as the expiratory reserve volume (ERV). The ERV is the additional amount of air that can be forcefully exhaled after a normal tidal exhalation. This concept is vital in understanding respiratory physiology and is used to assess lung function. During a respiratory cycle, the maximal amount of air that can be exhaled after maximal inspiration is known as the forced vital capacity (FVC). Both ERV and FVC are typically measured by spirometry, which can diagnose and monitor lung diseases such as asthma or pulmonary fibrosis through the FEV1/FVC ratio where FEV stands for the forced expiratory volume. A low FEV1/FVC ratio indicates resistance in the lungs, leading to slower exhalations as seen in asthma while a high ratio may indicate reduced lung compliance.