Which structure is primarily responsible for trapping bacteria in the respiratory system?

The correct answer is that the sinuses play a significant role in trapping bacteria and other pathogens in the respiratory system. The sinuses are air-filled cavities located within the bones of the skull, and they are lined with mucous membranes that produce mucus. This mucus serves as a trap for foreign particles, including bacteria, dust, and allergens that are inhaled.

When air enters the respiratory system, the sinuses help to moisten and warm the air, as well as filter it through the mucus they produce. The mucus can capture bacteria and other microorganisms, preventing them from reaching the lower airways and lungs. Cilia, tiny hair-like structures on the surface of the mucous membranes, aid in moving the mucus, along with trapped particles, out of the sinuses, helping to keep the respiratory system clear of infection and irritants.

The trachea and bronchi also have mucous membranes and cilia that help trap bacteria; however, they are part of the lower respiratory system and do not play a primary role in the initial filtering of inhaled air. The alveoli, on the other hand, are tiny air sacs in the lungs where gas exchange occurs and are not involved in trapping bacteria or particles. Instead, their primary function is