Question

Explain the respiratory volumes and capacities.

Answer 1

Capacity	Definition	Equivalent value
Inspiratory Capacity	The total volume of air a person can inspire after a normal expiration.	TV+IRV
Expiratory Capacity	The total volume of air a person can expire after a normal inspiration.	TV+ERV
Functional Residual Capacity	The volume of air that will remain in the lungs after a normal expiration.	ERV+RV
Vital Capacity	The maximum volume of air a person can breathe in after a forced expiration.	ERV+TV+IRV
Total Lung Capacity	The total volume of air accommodated in the lungs at the end of a forced inspiration	RV+ERV+TV+IRV

Respiratory Volume

Volume	Definition	Approx value
Tidal Volume	The volume of air inspired or expired during a normal respiration	6000-8000 ml of air per minute.
Inspiratory Reserve Volume	The additional volume of air, a person can inspire by a forcible inspiration.	2500-3000 ml
Expiratory reserve volume	The additional volume of air, a person can expire by a forcible expiration.	1000-1100 ml
Residual Volume	The volume of air maintaining in the lungs even after a forcible expiration.	1000-1200 ml