Medical Definition Search For ''
1. A surface-active agent, including substances commonly referred to as wetting agents, surface tension depressants, detergents, dispersing agents, emulsifiers, and quaternary ammonium antiseptics.
2. Those surface-active agents forming a monomolecular layer over pulmonary alveolar surfaces; lipoproteins, lecithins, and sphingomyelins that stabilize alveolar volume by reducing surface tension and altering the relationship between surface tension and surface area.