Most foreign substances in inspired air fail to reach the lungs because of the
A) ciliated epithelium and mucus that line the respiratory passages.
B) abundant blood supply to the nasal mucosa.
C) porous structure of the nasal conchae.
D) action of the epiglottis.

Question

Quizplus · Accepted Answer

The ciliated epithelium and mucus that line the respiratory passages trap and remove foreign substances, preventing them from reaching the lungs. The other options (B, C, and D) do contribute to the overall function of the respiratory system, but they are not the primary mechanisms for filtering out foreign particles.

Most Foreign Substances in Inspired Air Fail to Reach the Lungs