• Constantly recurring bacterial infections because thick mucus is not well removed from the lung. Changes in the lung airway surface liquid or ASL affect the body’s natural antibacterial defenses.

• Continuing inflammation that leads to scarring and loss of function. Because CF cells constantly produce chemicals that cause inflammation, even when there is no infection present, they cause more inflammation.

Think of your airway system as an upside-down tree. The trachea is a hollow trunk and the bronchioles, or small airways in the lungs, the smallest stems before the leaves. The outside of the "trunk" is made up of strong tissue and muscle, but is flexible to allow coughing. The inside of the trunk is covered by cells containing CFTR and other ion channels, cells with cilia and cells that make mucus and the ASL.

In CF, the ASL is abnormally thick and gooey because it contains thick mucus, bacteria, neutrophils -- white blood cells attempting to kill the bacteria -- and cell debris. These thick secretions block the smaller airways and make the airway swelling worse.

Select from the menu above to compare the normal lung aiway to the lung airway with CF and bacterial infection or with CF and inflammation.