When you breathe in, air first travels through your nose or mouth, and then through the trachea (windpipe), which further divides into bronchi, then smaller bronchioles, finally ending in the tiny air sacs (alveoli) in the lungs.
Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.