The alveolar epithelium serves as a barrier between the body and the external environment. To maintain efficient gas exchange. the alveolar epithelium has evolved to withstand and rapidly respond to an assortment of inhaled. injury-inducing stimuli. https://www.ngetikin.com/special-pick-MVP4-Moisture-Vapor-Protection-Anti-Fracture-and-Noise-Reduction-Membrane-special-save/