Cystic fibrosis is a chronic, hereditary, life-threatening disease that affects the body's organs, due to the buildup of thick, sticky mucus on the organs. The organs affected are the liver, lungs, pancreas and intestine, which causes damage to the respiratory, digestive and reproductive systems (Crust). Cystic fibrosis is caused by a mutation in a gene called the cystic fibrosis transmembrane regulator, also called CFTR, which has an important function of creating sweat, mucus and digestive juices (Crostra). The CFTR gene is a transporter gene that contains codes that tell cells how to behave. It is also found in the seventh chromosome, where it is responsible for regulating the movement of salt and water between cells. When the CFTR gene contains a mutation that is prevented from doing its job, cystic fibrosis occurs. There are approximately 1,500 CFTR mutations in six different categories, which are known to cause cystic fibrosis, although each category of mutations affects the CTFR gene differently. The mutation causes a change in the code, so sodium and chloride do not flow properly across the cell membrane. This causes the mucus to become thick and sticky, causing problems for people with cystic fibrosis (Alma). Normally, mucus is a slippery, watery substance that lines the organs to keep them moist and prevent dryness or infection, but when you have cystic fibrosis, the mucus is thick and sticky. Thick mucus builds up in the lungs and blocks the airways, making it easier for bacteria to grow. When the bacteria begin to grow, they cause serious lung infections and, over time, cause serious lung damage (“What is cystic fibrosis?”). Digestion problems can occur when thick mucus becomes blocked...... center of paper ......ine, 2012. Web. November 18, 2013. “Cystic Fibrosis and the Digestive System.” Lucile Packard Children's Hospital at Stanford. Lucile Packard Foundation for Children's Health, 2013. Web. November 18, 2013. “Cystic Fibrosis and the Reproductive System.” Lucile Packard Children's Hospital at Stanford. Lucile Packard Foundation for Children's Health, 2013. Web. November 18, 2013. “Cystic Fibrosis and the Respiratory System.” Lucile Packard Children's Hospital at Stanford. Lucile Packard Foundation for Children's Health, 2013. Web. November 18, 2013. Karleshiro, Neil K. “Cystic Fibrosis.” MedlinePlus medical encyclopedia. Seattle: ADAM, 2012. MedlinePlus. November 18, 2013. Mayo Clinic Staff. Cystic fibrosis. Mayo Clinic, 2012. Web. November 18, 2013. “What is Cystic Fibrosis?” National Heart, Lung, and Blood Institute. U.S. Department of Health and Human Services, 2011. Web. Nov. 18. 2013.