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

Question

Quizplus · Accepted Answer

Competition with the normal flora of the lungs actually helps to protect the lower respiratory tract by preventing colonization by harmful bacteria. The other options (IgA antibodies, mucous secretions, the ciliary escalator, and alveolar macrophages) all provide protection against potential pathogens in the lower respiratory tract.

The Lower Respiratory Tract Is Protected by All of the Following