|
Pulmonary surfactant is a surface-active lipoprotein complex (phospholipoprotein) formed by type II alveolar cells. The proteins and lipids that make up the surfactant have both hydrophilic and hydrophobic regions. By adsorbing to the air-water interface of alveoli hydrophilic head groups in the water and the hydrophobic tails facing towards the air, the main lipid component of surfactant, dipalmitoylphosphatidylcholine (DPPC), reduces surface tension. ==Function== * To increase pulmonary compliance. * To prevent atelectasis (collapse of the lung) at the end of expiration. * To facilitate recruitment of collapsed airways. Alveoli can be compared to gas in water, as the alveoli are wet and surround a central air space. The surface tension acts at the air-water interface and tends to make the bubble smaller (by decreasing the surface area of the interface). The gas pressure (''P'') needed to keep equilibrium between the collapsing force of surface tension (''γ'') and the expanding force of gas in an alveolus of radius ''r'' is expressed by the law of Laplace: : 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「pulmonary surfactant」の詳細全文を読む スポンサード リンク
|