What is the function of bronchioles?

What is the function of bronchioles?

• A. Gas exchange occurs here.
• B. Branch from secondary bronchi.
• C. Contain cartilage to keep open.
• D. Are lined with cilia to trap particles.

Answer: (B)

Bronchioles mainly serve to regulate air flow and clear inhaled debris as air moves toward the gas‑exchanging units. They lack cartilage, so their openness depends on smooth muscle tone and can widen or narrow to adjust airway resistance. Gas exchange does not occur here; it happens in the alveoli. The lining is ciliated epithelium, which helps move mucus and trapped particles out of the lungs—a key part of mucociliary clearance. Among common statements, the idea that bronchioles are lined with cilia to trap particles best reflects their functional role, while the other points describe features or processes not specific to bronchioles (gas exchange in alveoli, cartilage presence, and branching origin relative to other bronchi).

Bronchioles mainly serve to regulate air flow and clear inhaled debris as air moves toward the gas‑exchanging units. They lack cartilage, so their openness depends on smooth muscle tone and can widen or narrow to adjust airway resistance. Gas exchange does not occur here; it happens in the alveoli. The lining is ciliated epithelium, which helps move mucus and trapped particles out of the lungs—a key part of mucociliary clearance. Among common statements, the idea that bronchioles are lined with cilia to trap particles best reflects their functional role, while the other points describe features or processes not specific to bronchioles (gas exchange in alveoli, cartilage presence, and branching origin relative to other bronchi).