Which structure expands to bring in more air?

Which structure expands to bring in more air?

• A. Trachea
• B. Nasal Cavity
• C. Larynx
• D. Bronchioles

Answer: (A)

Airflow control during increased demand mainly comes from widening the small airways, the bronchioles. They contain smooth muscle that can relax to dilate the lumen, reducing resistance and allowing more air to reach the deeper parts of the lungs. The trachea stays open by cartilage rings and serves as a conduit rather than a site that expands to pull in more air. The nasal cavity affects air entry at the front end but doesn’t dynamically expand to increase overall ventilation. The larynx helps regulate airflow and protect the airway, but the key site for increasing inhaled air is the bronchioles through bronchodilation.

Airflow control during increased demand mainly comes from widening the small airways, the bronchioles. They contain smooth muscle that can relax to dilate the lumen, reducing resistance and allowing more air to reach the deeper parts of the lungs. The trachea stays open by cartilage rings and serves as a conduit rather than a site that expands to pull in more air. The nasal cavity affects air entry at the front end but doesn’t dynamically expand to increase overall ventilation. The larynx helps regulate airflow and protect the airway, but the key site for increasing inhaled air is the bronchioles through bronchodilation.