What is the function of a bronchiole in the respiratory system?

The bronchiole serves as a small terminal branch of a bronchus. In the respiratory system, bronchi split into smaller tubes called bronchioles, which further divide into even smaller air passages leading to the alveoli, where gas exchange occurs. These bronchioles are crucial for directing air into the deeper sections of the lungs, allowing for the efficient flow of air and ultimately playing a key role in the respiratory process.

The other options do not accurately reflect the primary function of bronchioles. Transporting air to the trachea is not their role; instead, bronchioles transport air from the bronchi to the alveoli. Filtering dust and particles is primarily a function of the upper respiratory structures, like the nasal passages and larger bronchi, rather than the bronchioles. Although gas exchange occurs in the lungs, it specifically happens in the alveoli, not in the bronchioles themselves.