2. Mainstem bronchus
3. Lobar bronchus
4. Segmental bronchus
6. Alveolar duct
The tertiary bronchi (also known as the segmental bronchi) arise from the secondary bronchi. The respiratory epithelium lining their lumen is surrounded by a layer of smooth muscle. This layer is composed of two ribbons of smooth muscle that spiral in opposite directions. The smooth muscle layer is surrounded by irregular plates of hyaline cartilage which help maintain the patency of the airway.
Each of the tertiary bronchi serves a specific bronchopulmonary segment. There are 10 tertiary bronchi in the right lung, and eight in the left.
The tertiary bronchi get smaller and divide into bronchioles.
Gartner, Leslie P. and James L. Hiatt. Color Textbook of Histology, 2nd ed. (2001). ISBN 0-7216-8806-3
- 1147863100 at GPnotebook
- Anatomy photo:19:17-0100 at the SUNY Downstate Medical Center - "Pleural Cavities and Lungs: The Bronchi and Their Divisions" (1/2)
- Anatomy photo:19:17-0200 at the SUNY Downstate Medical Center - "Pleural Cavities and Lungs: The Bronchi and Their Divisions" (2/2)