Browse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 Lungs The major features of the lungs include the bronchi, the bronchioles and the alveoli. The alveoli are the microscopic blood vessel-lined sacks in which oxygen and carbon dioxide gas are exchanged. Review Date: 12/4/2015 Reviewed By: The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.