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Respiratory bronchiole
Diagram of the alveoli with both cross-section and external view.
Schematic longitudinal section of a primary lobule of the lung (anatomical unit); r. b respiratory bronchiole; al. d alveolar duct; at atria; a. s alveolar sac; 'a' alveolus or air cell; p. a.: pulmonary artery; p. v pulmonary vein; l lymphatic; l. n lymph node.
Latin	bronchioli respiratorii
Gray's	subject #240 1098

The respiratory bronchioles are the beginning of the respiratory segment of the airway and are just distal to the terminal bronchioles (which are the last segment of the conducting airway). The epithelium in this segment is simple cuboidal. The respiratory bronchioles are interrupted by alveoli which are thin walled evaginations. Alveolar ducts are distal continuations of the respiratory bronchioles.

Additional images

Part of a secondary lobule from the depth of a human lung, showing parts of several primary lobules.

External links

• Diagram at davidson.edu
• Respiratory+bronchioles at eMedicine Dictionary
• Histology at BU 13606loa
• Histology at umdnj.edu