Which of These Does Not Act as a Protective Mechanism

Question

Which of these does not act as a protective mechanism in the respiratory system?
A) ciliated epithelium lining the respiratory tract
B) mucous lining the respiratory tract
C) alveolar macrophages in the lungs.
D) acidic secretions from the lining of the trachea

Accepted Answer

Acidic secretions from the lining of the trachea are not a protective mechanism in the respiratory system. In fact, the natural pH of the respiratory tract is slightly basic, which helps to protect against acid damage from reflux and other sources. The other options listed, ciliated epithelium, mucous lining, and alveolar macrophages, all act as protective mechanisms by trapping and removing pathogens and other irritants from the respiratory tract.