The smallest passageways in the lung to have ciliated epithelia are?

The smallest passageways in the lung to have ciliated epithelia are the terminal bronchioles. The terminal bronchioles are the smallest branches of the bronchial tree, and they lead to the alveoli, which are the tiny air sacs where gas exchange takes place. The cilia on the epithelia of the terminal bronchioles help to move mucus and debris out of the lungs.