Respiratory volumes and capacities
Tidal Volume The tidal volume is the total amount of air inhaled or exhaled during regular respiration or relaxed breathing. Approximately 500 ml of air is utilized during normal respiration in a healthy man. Inspiratory Reserve Volume An inspiratory reserve volume is a supplementary volume, approximately ranging between 2500 to 3100 ml of air which could be effectively inhaled after the inspiration of a standard tidal volume. Expiratory Reserve Volume An expiratory reserve volume refers to the additional capacity of air which is about 1200 ml are that could be forcibly exhaled out after the expiration of a standard tidal volume. Residual Volume/Reserve Volume The residual volume is about the total volume of air around 1100 ml to 1200 ml residing in the lungs after the reserve volume is emitted or breathed out. Total Lung Capacity The total lung capacity applies to the total volume of air-filled in the lungs after a forced inspiration. The lung capacity of a healthy man is estimated to be 6000 ml. TLC = TV + ERV + IRV + RV Vital Capacity The vital capacity is the total volume of air that can be expired after a maximum inhalation or maximum air that a person can breathe in after forced expiration. VC = TV + ERV + IRV Inspiratory Capacity The inspiratory capacity is the total volume of air that can be inspired which is about 3600 ml. IC = TV + IRV Functional Residual Capacity The functional residual capacity is the total volume of air residing within the lungs after an exhalation process and it is about 2400 ml. FRC = ERV + RV