This lung has been carefully split lengthwise, showing some of the bronchi as they branch to distribute air throughout the lung. The top of the trachea (longitudinally sectioned and indicated by the yellow arrow) is shown at the top of the photo.
One primary bronchus branches from the trachea at the yellow circle and is also sectioned along its longitudinal axis.
Smaller secondary bronchi branch from the primary bronchus at the holes indicated with the black arrows (only three indicated).
As the bronchi branch out through the lung, they split into smaller and smaller passages, the smallest of which are bronchioles, the terminal part of the air passages.
Back to: Respiratory system overview