Anatomy
air sac
air sac
Subclass of:
Animal Structures
Definitions related to air sacs:
  • A part of the respiratory system in multiple species (predominantly avian) which are variably connected with the lung.
    NCI
    U.S. National Cancer Institute, 2021
  • Thin-walled sacs or spaces which function as a part of the respiratory system in birds, fishes, insects, and mammals.
    NLM Medical Subject Headings
    U.S. National Library of Medicine, 2025
  • (air bladder) An organ in modern bony fish that develops from latral or dorsal wall of gut, and can fill with oxygen for bouyancy, hearing, or sound production.
    CRISP Thesaurus
    National Institutes of Health, 2006
  • Air sac, any of the air-filled extensions of the breathing apparatus of many animals. Air sacs are found as tiny sacs off the larger breathing tubes (tracheae) of insects, as extensions of the lungs in birds, and as end organs in the lungs of certain other vertebrates. They serve to increase...
    Encyclopedia Britannica
    Encyclopedia Britannica, Inc., 2025
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