Which of the following is the functional residual volume (FRV) ?

The correct answer is ERV + RV

Concept:

• The respiratory system includes various lung volumes and capacities, which are essential for understanding lung function and diagnosing respiratory conditions.
• Key lung volumes include Tidal Volume (TV), Expiratory Reserve Volume (ERV), Inspiratory Reserve Volume (IRV), and Residual Volume (RV).
• These volumes can be combined to form lung capacities, such as Expiratory Capacity (EC), Total Lung Capacity (TLC), and Functional Residual Capacity (FRC).

Explanation:

• Functional Residual Capacity (FRC): Volume of air that will remain in the lungs after a normal expiration. This includes ERV+RV.
• Inspiratory capacity (IC)  - Total volume of air a person can inspire after a normal expiration. This includes tidal volume and inspiratory reserve volume (TV+IRV).
• Expiratory Capacity (EC): Total volume of air a person can expire after a normal inspiration. This includes tidal volume and expiratory reserve volume (TV+ERV).
• Vital Capacity (VC) - The maximum volume of air a person can breathe in after a forced expiration. This includes ERV, TV and IRV
• Residual Volume (RV) - Volume of air remaining in the lungs even after a forcible expiration. This averages 1100 mL to 1200 mL.
• Tidal Volume (TV) - Volume of air inspired or expired during normal respiration. It is approx. 500 mL., i.e., a healthy man can inspire or expire approximately 6000 to 8000 mL of air per minute.