Question

What is the amount of air in a respiratory cycle?
(a)Air capacity
(b)Respiratory capacity
(c)Lung volume
(d)None of the above

Answer 1

Hint: After maximum inspiration, it is the maximum air volume that the lungs can hold or sum up all volume compartments or volume of air in the lungs. Around 6,000mL (4-6 L) is the standard value.

Complete answer:
The volume of the lungs and the capacity of the lungs apply to the volume of air in the lungs at various phases of the respiratory cycle. An adult human male's average total lung capacity is around 6 liters of air. Tidal Amount (TV): Amount of inspired or expired air during regular breathing. It's approx. 500 mL., i.e. approximately 6000 to 8000 mL of air per minute may be inhaled or expired by a healthy man. The average human breathing rate is 30-60 breaths per minute at birth, and in adults, it decreases to 12-20 breaths per minute. Hence, lung volume is the amount of air in the respiratory cycle.

Additional Information: The sum of two or more volumes is the respiratory capacity (pulmonary capacity). Factors such as age, gender, body composition, and physical conditioning affect the volumes and capacities of the lungs. In early adulthood, the lungs normally reach their full capacity and then decline with age.
The volume of air in the lungs following the maximum effort of inspiration is the lung capacity or total lung capacity (TLC). The average lung capacity is about 6 liters among healthy adults.
So, the correct answer is ‘Lung volume’.

Note: In the literature, four standard lung volumes are listed, namely, tidal (TV), inspiratory reserve (IRV), expiratory reserve (ERV), and residual volumes (RV). Alternatively, inspiratory (IC), functional residual (FRC), vital (VC), and complete lung potential (TLC) are the normal lung capacities.