What is the normal inspiratory reserve volume (IRV) in mL?

• A. 1000 mL
• B. 2000 mL
• C. 3000 mL
• D. 4000 mL

Answer: (C)

The normal inspiratory reserve volume (IRV) is typically around 3000 mL in a healthy adult. This volume represents the additional air that can be inhaled after a normal tidal breath, highlighting the capacity of the lungs to accommodate more air when necessary, such as during physical exertion or deep breathing exercises. Recognizing that IRV is a significant component of lung volumes helps in understanding respiratory mechanics and pulmonary function.

The IRV is an important measure in assessing lung function because it reflects the ability of the respiratory system to expand beyond normal tidal breathing. Values can vary among individuals based on various factors such as age, sex, body composition, and fitness levels, but the average tends to be close to the 3000 mL mark. Understanding these volumes is crucial in clinical practice, particularly in the evaluation of patients with respiratory conditions.