Breathing and exchange of gasses

Question

Given these lung volumes:

1. tidal volume = 500 mL

2. residual Volume = 1000 mL

3. inspiratory reserve volume = 2500 mL

4. expiratory reserve volume = 1000 mL

5. dead space = 1000 mL

The vital capacity is

1. 3000 mL.

2. 3500 mL.

3. 4000 mL.

4. 5000 mL.

5. 6000 mL.

Answer 1

Vital Capacity = 2500 mL + 500 mL + 1000 mL

= 4000 mL --> Option 3

Option C is the answer because residual volume and dead space can be ignored. These values are account for with inspiratory and expiratory reserve volume because there is actually room in the lungs even if someone has taken the biggest breathe in he or she could. The same goes for expiration.

Vital capacity deals with the lungs capacity for breathing. It does not deal with the values of carbon dioxide or oxygen exchange at lung surface. These values are used when dealing with gas exchange.