Source of elastic of the lung Elastic tissue(1/3)& Alveolar surface tension(2/3) Pulmonary surfactant Nature: A lipoprotein, Main lip component is DPL Characteristics: Both hydro-philia &-phobicity Source: Type I alveolar epithelial cells Distribution Inner surface of the alveoli Action: Reduce the alveolar surface tension Significance: Decrease the inspiratory resistance, Stabilize the volume &e pressure in the alveoli, Prevent pulmonary edemaSource of elastic ~ of the lung Elastic tissue (1/3) & Alveolar surface tension (2/3) Pulmonary surfactant Nature: A lipoprotein, Main lip component is DPL Characteristics: Both hydro-philia & -phobicity Source: Type II alveolar epithelial cells Distribution: Inner surface of the alveoli Action: Reduce the alveolar surface tension Significance: Decrease the inspiratory resistance, Stabilize the volume & pressure in the alveoli, Prevent pulmonary edema