- Alveolar duct
Name = PAGENAME
Caption = Detailed drawing of the alveoli from
Gray's Anatomy, 1918 - Schematic longitudinal section of a primary lobuleof the lung(anatomical unit);
al. d alveolar duct; at atria;
'a' alveolus or air cell;
Caption2 = Part of a secondary lobule from the depth of a human
lung, showing parts of several primary lobules.
2, respiratory bronchiole;
3, alveolar duct;
alveolusor air cell:
septumbetween secondary lobules.
Alveolar ducts are the tiny end ducts of the branching airways that fill the
lungs. Each lung holds approximately 1.5 to 2 million of them. The tubules divide into two or three alveolar sacs at the distalend. They are formed from the confluence openings of several alveoli. Distal terminations of alveolar ducts are atria which then end in alveolar sacs.
In human anatomy, respiratory
bronchiolesexists proximal to the alveolar ducts. The epithelial lining consists of smooth muscle knobs covered by nonciliated, simple cuboidal cells. The smooth muscle constricts under parasympathetic innervation and relax under sympathetic innervation.
* - "Alviolar Duct and Alveolar Sacs"
* - "Respiratory System: lung (sheep), alveolar duct "
* - "Mammal, lung (EM, Medium)"
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