Biology of surfactant

Surfactant is a metabolically active assembly of phospholipids and surfacta nt-specific proteins that is essential for normal lung mechanics. The surfa ctant proteins SP-A and SP-D also have important innate host defense functi ons. Surfactant metabolism in the developing lung differs from the adult lu ng by having slower kinetics of secretion with a longer half-life and more efficient recycling. Ventilation styles that injure the lung also result in altered surfactant function.