Fig. 1

a Diagram of the experimental setup used for in vitro measurements of mucociliary transport on the tracheal epithelium of perfused lamb trachea. Air-flow was set to 25 L/min and was directed from left to right while mucociliary transport was from right to left. The ultrasonic nebulizer was introduced to the air path before the organ bath. Video-microscopy recordings were made through the heated optical window on the top of the tracheal bath to measure mucociliary transport along the tracheal epithelial surface. b Photo of the in vitro experiment setup with the trachea mounted in the organ bath, with circulation of Krebs–Henseleit solution below. The microscope with coaxial illumination is shown above