ABSTRACT
This chapter describes the functional composition and component biophysics of endogenous lung surfactant. A functional view of composition is essential for all lung surfactants. Endogenous lung surfactant is a complex mixture of lipids and proteins, chemical classes present in all cells and tissues. Functional components in lung surfactant are those that generate the surface properties required for physiological activity. This chapter discusses the chemical components of lung surfactant in the context of their biophysical actions and importance in adsorption and dynamic surface activity. Primary functional constituents in endogenous surfactant include DPPC, a mix of additional saturated and unsaturated phosphatidylcholines and other phospholipid classes, and surfactant proteins SP-A, SP-B, and SP-C. Neutral lipids also influence surface activity, while a fourth surfactant protein SP-D does not affect biophysical function.
