The lower respiratory tract is protected by all of the following EXCEPT
A) the ciliary escalator.
B) alveolar macrophages.
C) mucous secretions.
D) IgA antibodies.
E) competition with the normal flora of the lungs.

Question

Quizplus · Accepted Answer

The lower respiratory tract is protected by mechanisms like the ciliary escalator, alveolar macrophages, mucous secretions, and IgA antibodies, but it does not rely on competition with normal flora, as the lungs are typically sterile and do not have a normal flora.

The Lower Respiratory Tract Is Protected by All of the Following