Breathing and Exchange of Gases - Respiratory volumes

Tidal Volume ($TV$): Volume of air inspired or expired during a normal respiration. It is approx. $500\text{ mL}$ in a healthy man (about $6000\text{ mL}$ to $8000\text{ mL}$ of air per minute).

Inspiratory Reserve Volume ($IRV$): Additional volume of air, a person can inspire by a forcible inspiration. This averages $2500\text{ mL}$ to $3000\text{ mL}$.

Expiratory Reserve Volume ($ERV$): Additional volume of air, a person can expire by a forcible expiration. This averages $1000\text{ mL}$ to $1100\text{ mL}$.

Residual Volume ($RV$): Volume of air remaining in the lungs even after a forcible expiration. This averages $1100\text{ mL}$ to $1200\text{ mL}$.

Inspiratory Capacity ($IC$): Total volume of air a person can inspire after a normal expiration. It includes $TV$ and $IRV$.

Expiratory Capacity ($EC$): Total volume of air a person can expire after a normal inspiration. It includes $TV$ and $ERV$.

Functional Residual Capacity ($FRC$): Volume of air that will remain in the lungs after a normal expiration. This includes $ERV$ and $RV$.

Vital Capacity ($VC$): The maximum volume of air a person can breathe in after a forced expiration, or the maximum volume of air a person can breathe out after a forced inspiration ($ERV + TV + IRV$).

Total Lung Capacity ($TLC$): Total volume of air accommodated in the lungs at the end of a forced inspiration. This includes $RV$, $ERV$, $TV$ and $IRV$.

Spirometer: An instrument used to measure the volume of air involved in breathing movements, which helps in clinical assessment of pulmonary functions.