Lungs - illustration
Upper respiratory tract - illustration
Upper respiratory tract
Lower respiratory tract - illustration
Lower respiratory tract
Review Date: 10/10/2020
Reviewed By: Linda J. Vorvick, MD, Clinical Associate Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.