air sac

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Related to alveolar sac: Alveolar ducts

air sac

[′er ‚sak]
(geology)
(invertebrate zoology)
One of the large, thin-walled structures associated with the tracheal system of some insects.
(vertebrate zoology)
In birds, any of the small vesicles that are connected with the respiratory system and located in bones and muscles to increase buoyancy.
References in periodicals archive ?
Adult tucuxi left lung photomicrograph (HE); B: Photomicrograph of the detail of adult tucuxi (HE) left lung; C: Adult bronchodilator (HE) photomicrograph; D: Photomicrograph of detail of the presence of myoelastic sphincters in the adult tucuxi lung (HE); E: Photomicrograph of adult tucuxi alveolar sacs (SEM); F: Photomicrograph of the alveolar walls of adult boto alveolar sacs (arrow) (SEM).
Idiopathic pulmonary fibrosis (IPF) is a progressive, fatal lung disease in which fibrous tissue replaces the alveolar sacs through which we breathe.