Presentation on theme: "What causes cystic fibrosis?"— Presentation transcript:
1 What causes cystic fibrosis? A mutation in the cystic fibrosis transmembrane regulatory protein
2 What does the CFTR protein do? It helps control the viscosity (or stickiness) of mucus that lines the epithelial cells of the airways, digestive and reproductive systemsmucusciliaepithelial cellIf the mucus in airways is…too sticky: the cilia cannot beat and remove the mucus, which then clogs up airwaystoo runny: the mucus can flood the airways
3 When there is excess water in the mucus Water is drawn out of the mucus and it thickensCl-Na+H2Omucus2apical membrane5CFTR channel closedNa+channel openH2Opump1basal membrane43tissue fluidH2OCl-Na+
4 When there is too little water in the mucus Water is drawn out of the mucus and it becomes less stickyCl-Na+Na+mucus324apical membraneNa+channelclosedCFTR channel openH2OThe CFTR somehow blocks the sodium channelsCl-1H2Obasal membrane5pumptissue fluidH2ONa+
5 With cystic fibrosis X The mucus becomes very thick and sticky mucus Cl-Na+H2Omucus123Xapical membraneCFTRnon-functionalThe CFTR protein cannot block the sodium channels so they are always openWater drawn out by osmosisNa+channelopenH2Obasal membraneH2Otissue fluidCl-
6 How cystic fibrosis affects the lungs Sticky mucus builds up in the airways, reducing flow of air into alveoli. Lungs gradually fill up with mucus, making them less effective for gas exchange.Symptoms:Severe coughing - to remove excess mucus.Breathlessness - shortage of oxygen increases tiredness and lack of energyInfections - as bacteria are trapped in mucus
7 How does cystic fibrosis affect the reproductive systems? MenWomenSperm duct is blocked and prevents movement of spermDuring the menstrual cycle the levels of mucus vary.Can lack the sperm ductsWomen with CF have thick levels of mucus which can block the cervix so sperm cannot reach them.
8 How cystic fibrosis affects the digestive system: Thick, sticky mucus blocks the pancreatic duct preventing enzymes from reaching the duodenum. Food is not digested and absorbed sufferers fail to put on body mass and suffer malnutrition.Trapped digestive enzymes damage the pancreatic cells affecting cells producing insulin resulting in diabetes.