Table 3 Composition of lung lining fluid in conducting airways and respiratory zone (from (Eixarch et al. 2010) and (Hastedt 2014))
Conducting airways | Respiratory Zone | |
|---|---|---|
Principal lining fluid | Mucus | Surfactant |
Composition of fluid layer | 1 % inorganic salts | 85 % phospholipids |
1 % proteins | 5 % cholesterol | |
2 % glycoproteins (mucins) | 10 % surfactant proteins (e.g., SP-A, SP-B, SP-C, SP-D) | |
1 % lipids | ||
95 % water | ||
Layer thickness | 3–15 μm (decreases in thickness in lower airways) | ~0.07 μm |
Approximate volume | 10–30 ml | 7–20 ml |