Question

Volume of air which remain in lungs after maximal expiration is called as:

• A. Total lung capacity
• B. Residual volume
• C. Tidal volume
• D. Vital capacity of lungs

Answer 1

The correct option is B Residual volume

The air in the lungs is measured in terms of lung volume and lung capacity. Lung volume measures the amount of air for inhalation or exhalation. Whereas, lung capacity measures how much air can be inhaled from the end of a maximal exhalation.

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.

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.

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

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