A Level Biology Practice Exam

What is the primary role of the trachea in the respiratory system?

1. to filter pollutants from the air before it enters the lungs

2. to carry warm, moist air from the nasal cavity to the lungs

3. to exchange gases with the bloodstream

4. to provide structural support to the bronchial tubes

The correct answer is: to carry warm, moist air from the nasal cavity to the lungs

The primary role of the trachea in the respiratory system is to carry warm, moist air from the nasal cavity to the lungs. The trachea, also known as the windpipe, is a flexible tube that connects the larynx to the bronchi, which branch into the lungs. It is lined with mucous membranes and ciliated epithelial cells that help trap and move particles out of the airway, ensuring that the air reaching the lungs is both warm and humidified. This conditioning of the air is critical because it helps protect the delicate tissues of the respiratory system from irritation and damage that can be caused by cold or dry air. While filtering pollutants and providing structural support are important functions related to air passage and lung function, and gas exchange is a crucial aspect of respiration, the trachea's specific function centers primarily on facilitating the movement of air in a conditioned state to the lungs. The other roles mentioned involve different structures or processes within the respiratory system, underscoring the trachea's distinct and important function in air transport.