MucusCervix MucusMucinsMucociliary ClearanceMucin-2Gastric MucinsMucin 5ACGoblet CellsExocrine GlandsMucin-5BIntestinal MucosaGastric MucosaRespiratory MucosaPeriodic Acid-Schiff ReactionExpectorantsTracheaMucin-3BronchiRespiratory SystemViscosityThoracic DiseasesCystic FibrosisScienceLung DiseasesWales