Regulating mucus water content in unaffected/affected lungs

Excess water in the mucus is detected by the epithelial cell membranes that line the airways...

1) Na+ is actively pumped across the basal membrane

• Concentration gradient created across the apical membrane as the concentration of Na+ falls in the cell

2) Na+ diffuses through Na channels in the apical membrane

• Raised concentration of Na+ in tissue fluid creates a PD between the tissue fluid and mucus

3)…