air sac 名詞
肺泡,氣囊
Air sac
1. Anat. One of the spaces in different parts of the bodies of birds, which are filled with air and connected with the air passages of the lungs; an air cell.
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air sac
n 1: a tiny sac for holding air in the lungs; formed by the
terminal dilation of tiny air passageways [syn: alveolus,
air cell]
2: any of the thin-walled extensions of the tracheae of insects
3: any of the membranous air-filled extensions of the lungs of
birds