The Sweat Gland
In normal skin, sweat is produced in glands under the skin, travels to the skin’s surface through small tubes, or ducts, and is then reabsorbed. The sweat is made up of water, sodium (Na+), chloride (Cl-) and a little potassium. In science class, you have probably learned a little about positive and negative charges on atoms that make them stick together to form one molecule. Sodium and chloride usually travel together so that the positive and negative charges balance each other.

In CF patients, however, the salt is not easily reabsorbed because the CFTR protein will not allow the chloride to reenter the skin. Because the opposite charges on sodium and chloride make them travel together, sodium movement is also blocked. This is why your skin tastes saltier than someone who doesn’t have CF.

The Lung
The inside of your lungs are covered with a thin, moist film called airway surface liquid, or ASL, a salt-containing liquid and a mucus gel layer. The job of the ASL is to trap incoming bacteria and foreign particles, while cilia -- millions of microscopic hair-like projections on your airways -- do their job of constantly moving particles out of the lungs and toward the mouth to protect the lungs from infection. ASL also contains substances like antioxidants and antibodies that neutralize or destroy invading organisms without damaging the lungs. In CF airways, decreased chloride transport is coupled with excess sodium transport out of the surface liquid. Because water follows the flow of sodium, the ASL loses volume and the mucus gel layer becomes dehydrated. Consequently, cilia cannot move out inhaled bacteria and the airways begin to clog and become chronically infected.

Select the "Lung - Airway Cell" or "Sweat Gland Cell" above to compare the function of a normal cell to a cell with CF.

The Pancreas
Digestive enzymes and a bicarbonate-rich (HCO3) fluid combine within the pancreas to form a non-acidic mixture that maximizes enzyme function. Without enzymes, proteins that speed up chemical reactions, our bodies would grind to a halt. While CF patients may have normal pancreatic gland cell secretion, bicarbonate fluid secretion is decreased. The two transport pathways involved in bicarbonate secretion, and the way the CFTR interacts with these exchangers, are being researched.