Question

A person has 400 million alveoli per lung with an average radius of 0.1m for each alveolus. Considering the alveoli are spherical in shape, the total respiratory surface of that person is closest to.

• A. $500m{m}^2$
• B. $200m{m}^2$
• C. $100m{m}^2$
• D. $1000m{m}^2$

Answer 1

The correct option is D $1000m{m}^2$

in lungs, alveoli are tiny sacs which allow oxygen and carbon dioxide to move between the lungs and bloodstream.

Average radius of spherical alveoli is 0.1 mm

Total number of Alveoli is 400 × 2 = 800 million (since 400 million alveoli in 1 lung)

Surface area of a sphere is 4π$r^2$

Therefore, total respiratory surface Area = 4π$r^2$ × 800 million= 1000$m$$m^2$ (approx)

Thus the correct answer is option D.