1. Health
Send to a Friend via Email

What are Alveoli?

By

Updated October 30, 2012

What are Alveoli? A.D.A.M. Medical Encyclopedia
Definition:

Alveoli are the tiny air sacs (only 1 cell thick) in the lungs at the end of the smallest airways, where the exchange of oxygen and carbon dioxide takes place. The average human has nearly 300 million alveoli to absorb oxygen from the air.

Learn how your lungs work:

Examples:
Jim was diagnosed with bronchioalveolar carcinoma, a type of lung cancer that begins in the alveoli.

©2014 About.com. All rights reserved.

We comply with the HONcode standard
for trustworthy health
information: verify here.