When you breathe, the airway (respiratory) system
supplies oxygen to your blood. Then your blood takes oxygen to all parts of the
body.
The nose, mouth, throat (pharynx and larynx), and hollow
spaces in the cheeks and around the eyes (sinuses) make up the upper
respiratory tract. The windpipe (trachea), breathing tubes (bronchial tubes and
bronchioles), and structures inside the lungs make up the lower respiratory
tract.
Last Updated:July 16, 2008
Medical Review:Michael J. Sexton, MD - Pediatrics & W. David Colby IV, MSc, MD, FRCPC - Infectious Disease