Ciliary beat frequency in human bronchi and bronchioles.

STUDY OBJECTIVE This study aimed to determine the differences between ciliary beat frequencies of respiratory ciliated cells from peripheral bronchioles and from proximal bronchi in humans. DESIGN Measurements were made from resected lungs. Ciliated cells were harvested by brushing the mucosa of each site immediately after surgery. Brushings with a cytology brush were performed on normal areas of the resected cartilaginous bronchus for proximal samplings and through a peripheral bronchiole close to the visceral pleura for peripheral samplings. For each site, at least 12 different measurements were made at 22 degrees C using an image analysis system. RESULTS A highly significant difference between proximal bronchi (mean, 7.1 Hz; SD, 1.29) and peripheral bronchioles (mean, 4.6 Hz; SD, 1.39) (p < 0.0001) was found. CONCLUSION Thus, cilia from peripheral bronchioles beat at a 35% lower beat frequency than cilia from proximal bronchi.