Which value is considered as the vital capacity when calculated with the formula VC = ERV + TV + IRV?

The vital capacity is defined as the maximum amount of air that can be exhaled after a maximum inhalation, which is the sum of the expiratory reserve volume (ERV), tidal volume (TV), and inspiratory reserve volume (IRV).

An approximate value of 4,700 mL is considered a general average for vital capacity in a healthy adult. This value can vary based on individual differences such as age, sex, body composition, and lung health. The individual components of the capacity contribute to this total: ERV is the amount of air that can be pushed out after a normal expiration, TV is the amount of air inhaled or exhaled during normal breathing, and IRV is the amount of air that can be inhaled after a normal inhalation.

Understanding this, the approximate value of 4,700 mL accurately reflects a typical measurement for vital capacity, illustrating the total volume of air that can be manipulated during respiration within a normal physiological range. The other values provided may represent normal lung capacities for other measurements, like total lung capacity, but they do not represent the vital capacity as defined by the components outlined.