Tertiary bronchus 2918174 141581065 2007-06-30T11:23:07Z 87.242.142.6 {{Infobox Anatomy | Name = {{PAGENAME}} | Latin = bronchi segmentales | GraySubject = | GrayPage = | Image = illu_quiz_lung05.jpg | Caption = 1. [[Vertebrate trachea|Trachea]]<BR>2. [[Mainstem bronchus]]<BR>3. [[Secondary bronchus|Lobar bronchus]]<BR>4. [[Tertiary bronchus|Segmental bronchus]]<BR>5. [[Bronchiole]]<BR>6. [[Alveolar duct]]<BR>7. [[Pulmonary alveolus|Alveolus]] | Image2 = | Caption2 = | System = | MeshName = | MeshNumber = | DorlandsPre = b_23 | DorlandsSuf = 12198382 | }} The '''tertiary bronchi''' (also known as the '''segmental bronchi''') arise from the [[secondary bronchus|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 [[primary bronchiole]]s. ==Additional images== <gallery> Image:Illu bronchi lungs.jpg|Bronchi, bronchial tree, and lungs Image:Terminal bronchiole.JPG|Cross sectional cut of terminal bronchiole Image:Respiratory_bronchus2.JPG|Human respiratory bronchiole. </gallery> ==References== Gartner, Leslie P. and James L. Hiatt. <u>Color Textbook of Histology, 2nd ed.</u> (2001). ISBN 0-7216-8806-3 ==External links== * {{GPnotebook|1147863100}} * {{SUNYAnatomyLabs|19|17|01|00}} - "Pleural Cavities and Lungs: The Bronchi and Their Divisions" (1/2) * {{SUNYAnatomyLabs|19|17|02|00}} - "Pleural Cavities and Lungs: The Bronchi and Their Divisions" (2/2) {{Lung}} [[Category:Respiratory system]] [[Category:Human anatomy]] [[Category:Thorax]]