Air sac

Air sac generally refers to an organ or portion of an organ containing air within an animal's respiratory system.

Air sac may refer to

• Pulmonary alveolus, small hollow cavities which are a part of the lungs within mammals
• Air sacs, structures unique to the saurischian dinosaur respiratory system, among it the extant bird respiratory system which has posterior and anterior air sacs, which are separate from the animal's lungs

See also

• Lung § Reptiles