What is total lung capacity?

What is total lung capacity?

• A. Air at the end of normal respiration.
• B. The amount of air at the end of maximal exhalation.
• C. Sum of all 4 lung volumes, total amount of air a lung can hold.
• D. Volume moved per minute.

Answer: (C)

Total lung capacity is the maximum amount of air the lungs can hold after a full, deep breath. It’s found by adding together all four lung volumes: tidal volume (air moved with normal breathing), inspiratory reserve volume (extra air you can inhale beyond a normal inspiration), expiratory reserve volume (extra air you can exhale below a normal expiration), and residual volume (air remaining in the lungs after a full exhale). Because residual volume can’t be expelled, TLC represents the complete capacity of the lungs to hold air, typically around 4–6 liters in a healthy adult but varying with size and fitness. This is different from air at the end of normal breathing (a point within the breathing cycle) or air moved per minute (which is minute ventilation).

Total lung capacity is the maximum amount of air the lungs can hold after a full, deep breath. It’s found by adding together all four lung volumes: tidal volume (air moved with normal breathing), inspiratory reserve volume (extra air you can inhale beyond a normal inspiration), expiratory reserve volume (extra air you can exhale below a normal expiration), and residual volume (air remaining in the lungs after a full exhale). Because residual volume can’t be expelled, TLC represents the complete capacity of the lungs to hold air, typically around 4–6 liters in a healthy adult but varying with size and fitness. This is different from air at the end of normal breathing (a point within the breathing cycle) or air moved per minute (which is minute ventilation).