ABSTRACT
This chapter will deal with how the mucus reacts to particles and particulate loads, thereby altering its rate of clearance. Particles can stimulate secretion and modulate ciliary function, either by mechanical factors or irritation, or by the chemicals they contain or are capable of releasing. Particles have a direct effect on the physical properties of mucus, even when acting as a ‘‘neutral filler,’’ for which their contribution to viscoelasticity is a simple function of their volume fraction. Beyond this, particles may interact with the mucous gel network, and add multiple cross-link points.
