Final answer:
The Inspiratory Reserve Volume (IRV) is the volume of air that can be further inhaled after a normal inhalation, during a forceful inspiration.
Step-by-step explanation:
The volume of air forcefully inhaled on top of a normal inspiration is called the Inspiratory Reserve Volume (IRV). This is the extra air volume that can be inhaled during a forceful inspiration beyond what is taken in during regular, quiet breathing (tidal volume). After normal inhalation, if you were to take a deep, additional breath in, the air volume inhaled during this process would be your IRV. It is essential for providing flexibility in respiratory capacity to meet the body's oxygen demands during increased activity or exercise.