Question

multiple choice 2 points
healthy paranasal sinuses are filled with mucus.
false
true

Explanation:

Define paranasal sinuses

Paranasal sinuses are air-filled cavities within the bones of the skull surrounding the nasal cavity.

Analyze normal sinus contents

In a healthy individual, these cavities are filled with air, not fluid or mucus. They are lined with a ciliated mucous membrane that produces a thin layer of mucus to trap dust and pathogens, which is then continuously swept by cilia into the nasal cavity for drainage.

Evaluate the statement

The statement claims that healthy paranasal sinuses are "filled with mucus." Since healthy sinuses are filled with air and only have a thin lining of mucus, being filled with mucus is a sign of congestion or infection (such as sinusitis). Therefore, the statement is false.

Answer:

• (A) false (Correct answer)
• (B) true