Table 2 Characteristic Cell Numbers and Lung Values

Alveolar Surface Area

143

m²

(Gehr et al. 1978)

# of alveoli (adult lung)

250+

Million

(Crapo et al. 1982)

# of type I pneumocytes

1.9

Billion

(Crapo et al. 1982)

# of type II pneumocytes

3.7

Billion

(Crapo et al. 1982)

# of resident macrophages

2.3

Billion

(Crapo et al. 1982)

Depth of airway fluid

5–10

um

(Widdicombe 2002)

Harmonic mean depth of alveolar fluid

0.2

um

(Bastacky et al. 1995)

Diameter of an alveolus

200–250

um

(Parent 1982)