Alveolar duct

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Alveolar duct
An alveolus, is an anatomical structure that has the form of a hollow cavity. Mainly found in the lung, the pulmonary alveoli are spherical outcroppings of the respiratory bronchioles and are the.png
An alveolus showing an alveolar duct
Details
SystemRespiratory system
FunctionTransmission of air from respiratory bronchioles to alveolar sacs
Identifiers
LatinDuctus alveolaris
THH3.05.02.0.00022
FMA7341
Anatomical terminology

Alveolar ducts are tiny ducts that connect the respiratory bronchioles to alveolar sacs, each of which contains a collection of alveoli (small mucus-lined pouches made of flattened epithelial cells). They are 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 distal end. 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 bronchioles exist 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.

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