What is the function of the respiratory mucosa? As with all mucus in the body, its a lubricant to keep the lungs moist, prevents the lung lining from sticking to itself and prevents foreign body's like bacterium and dust fr … om in bedding into the lungs causing infection.pecialized membrane that lines the air distrubution tubes in the respiratory tree. Over 125ml of mucus produced each day forms a mucous blanket over much of the respiratory … mucosa. Mucus serves as an air purification mechanism by trapping inspired irritants such as dust and pollen etc.