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Alveoli- Definition of Alveoli


Updated December 28, 2010

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Alveoli are tiny grape-like sacs where gas exchange (oxygen and carbon dioxide) takes place in the lungs.

When you breathe out, the body delivers carbon dioxide to the alveoli, and you release it in your exhalation. When you breathe in, oxygen fills the alveoli and then enters the blood, so it can be delivered to the rest of the body.

In asthma, there is no damage to the alveoli, which is different from another common lung disease -- chronic obstructive pulmonary disease -- in which alveoli are damaged.

More About Alveoli

Pronunciation: al-VEE-oh-lye
Also Known As: air sacs
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