PERMEABILITY OF THE BLOOD–GAS BARRIER

摘要: Two continuous membranes separate the blood and gas phases of alveoli: endothelium epithelium. Gases readily dissolve in cellular both layers rapidly exchange between air. Carbon monoxide is generally used to monitor gaseous diffusion. Electrolytes water can cross intercellular junctions, but molecules also traverse a variety specific channels (aquaporins) cell membranes. The restrains movement proteins relatively permeable electrolytes. Transcapillary edema formation governed by hydrostatic protein osmotic gradients (Starling forces). epithelium resists passive electrolytes proteins, airspace primarily restrained buffering Capillary injuries, including elevations capillary pressures, result leakage red cells into interstitium, from where they make their way airspaces if ruptured increases interstitial pressure. Edema fluid normally reabsorbed active sodium transport. Uncertainty persists regarding osmolality airway fluid, methods collecting respiratory (bronchoalveolar lavage exhaled breath condensates) have been complicated uncertainty dilution. Increased epithelial permeability solutes be detected accelerated clearance radioaerosols lungs.