WHAT IS CYSTIC FIBROSIS? It's a disease caused by a defective gene that affects the lungs and digestive system. The body produces thick mucus that clogs the lungs and pancreas, making it difficult to breathe and digest food, respectively. Symptoms of the disease include coughing, wheezing, lung infections and delayed growth and weight gain. Treatment and care advanced greatly during the 20th century, lengthening lives by decades, but cystic fibrosis remains a dangerous disease, with the median age of predicted survival of someone affected by it being 37.4 years in 2008.
ABOUT THE LUNGS: The lungs are located in the chest cavity, and are protected by the rib cage. The lungs are responsible for the exchange of oxygen and carbon dioxide between the body and its surrounding environment. They are made of a spongy, elastic type of tissue filled with tiny holes or bubbles, each surrounded by a fine network of tiny blood vessels. This tissue stretches and contracts as you breathe. The total surface area of the lungs is about the size of a football field. When you breathe in, the diaphragm and intercostals or chest wall muscles contract, causing the air to travel from your nose and mouth through the windpipe (trachea), then through large and small tubes in the lungs called bronchial tubes. At the end of these tubes are groups of tiny air sacs called alveoli. They have very thin walls filled with small blood vessels called capillaries. Oxygen passes from the air sacs into the blood vessels, and carbon dioxide -- the waste byproduct from the body's metabolism -- passes from the blood into the air sacs. The carbon dioxide is then expelled into the atmosphere when you exhale.