MucusCervix MucusMucinsMucociliary ClearanceMucin-2Gastric MucinsMucin 5ACGoblet CellsIntestinal MucosaExocrine GlandsMucin-5BGastric MucosaPeriodic Acid-Schiff ReactionRespiratory MucosaGerm LayersTracheaExpectorantsSmear LayerMicroscopy, Electron, ScanningMucin-3ViscosityBronchiRespiratory SystemMicroscopy, ElectronColonBacterial AdhesionRetina