Final answer:
Gas exchange in the respiratory tract occurs in the alveoli, where oxygen and carbon dioxide are exchanged between the air and the blood. In cystic fibrosis, excess mucus impairs this process.
Step-by-step explanation:
In cystic fibrosis, the respiratory tract can become clogged with mucus, which poses challenges for gas exchange. This crucial process of exchanging gases such as oxygen and carbon dioxide occurs in specialized structures within the lungs known as alveoli. These tiny air sacs are surrounded by capillaries and are the site where the blood delivers carbon dioxide and picks up oxygen. The lower respiratory tract includes the trachea, bronchi, and bronchioles that primarily serve as a conduit for air to reach the alveoli in the lungs. Despite the essential protective role of mucus in trapping pathogens and particles in the air, the excessive buildup seen in conditions like cystic fibrosis can severely affect the respiratory functions.