Video 3

Movie S3. Ventral view of the movement of fluorescent microspheres in water-filled lungs. Craniad is toward the bottom right hand corner of the field of view. The medial region of both lungs can be seen. The right lung contains an air bubble visible in the upper left hand corner of the field of view. The bubble can be seen moving toward the top of the screen as water is infused into the lungs and toward the bottom as it is withdrawn. In the ventromedial regions of both lungs microspheres move craniad during both phases of respiration. A few of the microspheres can be seen moving laterocaudad in the high-velocity fluid stream on inspiration.