The effects of mucus and mucilaginous materials on ion-distributions at epithelial surfaces

Mucous layers on epithelial surfaces may have a range of functions. One approach used to investigate these is to measure the distribution of ions within the mucous layers using ion-sensitive microelectrodes. The results of several studies are reviewed. It is clear that these layers do influence the distribution of ions at epithelial surfaces and by a variety of mechanisms. Processes such as active ion-transport and passive diffusion interact with the diffusional and ion-exchange properties of mucus to produce complex distributions.