Pulmonary surfactant film at the alveolar air-liquid interface (null)

The **pulmonary surfactant film at the alveolar air-liquid interface** is a biophysically active, molecularly organized surface layer, composed predominantly of phospholipids (notably dipalmitoylphosphatidylcholine), cholesterol, and four main surfactant proteins (SP-A, SP-B, SP-C, and SP-D). Secreted by type II alveolar epithelial cells, this film rapidly adsorbs to the alveolar air-liquid interface where it reduces surface tension to near-zero during exhalation, thus preventing alveolar collapse and lowering the work of breathing. The surfactant system is essential for lung stability and efficient gas exchange; deficiencies or dysfunctions cause significant respiratory diseases, including neonatal and acute respiratory distress syndromes. While surfactant is not a canonical drug target, it is therapeutically manipulated by exogenous surfactant therapy, and its molecular components (especially surfactant proteins) are the subject of diagnostic and therapeutic research [1][2][3][5][7].

Other names

pulmonary surfactant layeralveolar surfactant filmalveolar surface filmair-liquid interface (ALI) of the lung

Exogenous surfactant supplementation restores or replaces deficient surfactant layer, quickly reducing surface tension at the air-liquid interface and improving lung compliance and oxygenation