Question

A typical adult human lung contains about 330 million tiny cavities called alveoli. Estimate the average diameter of a single alveolus. Assume the alveoli are spherical and a typical human lung is about 1.9 liters.

Answer 1

Answer:

The average diameter of a single alveolus is 0.0222 cm.

Explanation:

Volume of the lung ,V= 1.9 L

$1 L = 1000 cm^3$

$1.9 L=1.9\times 1000 cm^3=1900 cm^3$

Number of alveoli in a human lung = $330\times 10^6$

Volume of single alveoli =v

$v\times 330\times 10^6=V$

$v=\frac{1900 cm^3}{330\times 10^6}$

$v=5.7575\times 10^{-6} cm^3$

The alveoli are spherical.

Radius of an alveolus = r

Volume of the sphere = $\frac{4}{3}\pi r^3$

$v=\frac{4}{3}\pi r^3$

$5.7575\times 10^{-6} cm^3=\frac{4}{3}\times 3.14\times r^3$

$r=0.0111 cm$

Diameter of the alveolus =d

d = 2r = 2 × 0.0111 cm = 0.0222 cm

The average diameter of a single alveolus is 0.0222 cm.