Final answer:
The sum of IRV (Inspiratory Reserve Volume) and TV (Tidal Volume) gives us the Inspiratory Capacity (IC), representing the maximum volume of air that can be inhaled after a tidal expiration.
Step-by-step explanation:
IRV (Inspiratory Reserve Volume) plus TV (Tidal Volume) provides us with the Inspiratory Capacity (IC). The Inspiratory Capacity is the amount of air that can be inhaled past a normal tidal expiration. In more detail, IRV is the extra volume of air that can be inhaled with effort after a normal inhalation, while TV represents the normal volume of air that moves in and out of the lungs during restful breathing. Together, they measure the total amount of air a person can draw into their lungs after completing a typical exhalation.