Presentation on theme: "What causes cystic fibrosis? A mutation in the cystic fibrosis transmembrane regulatory protein."— Presentation transcript:
What causes cystic fibrosis? A mutation in the cystic fibrosis transmembrane regulatory protein
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 systems too runny: the mucus can flood the airways mucus cilia epithelial cell If the mucus in airways is… too sticky: the cilia cannot beat and remove the mucus, which then clogs up airways
When there is excess water in the mucus mucus tissue fluid CFTR channel closed Na + channel open pump Na + H2OH2O H2OH2O Cl - apical membrane basal membrane Water is drawn out of the mucus and it thickens Cl - H2OH2O
When there is too little water in the mucus mucus tissue fluid CFTR channel open Na + channel closed Na + H2OH2O H2OH2O Cl - apical membrane basal membrane Cl Water is drawn out of the mucus and it becomes less sticky Na + H2OH2O The CFTR somehow blocks the sodium channels pump
With cystic fibrosis mucus tissue fluid CFTR non- functional Na + channel open Na + H2OH2O H2OH2O Cl - apical membrane basal membrane X Water drawn out by osmosis 1 23 The mucus becomes very thick and sticky Cl - H2OH2O The CFTR protein cannot block the sodium channels so they are always open
How cystic fibrosis affects the lungs Symptoms: Severe coughing - to remove excess mucus. Breathlessness - shortage of oxygen increases tiredness and lack of energy Infections - as bacteria are trapped in mucus 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.
How does cystic fibrosis affect the reproductive systems? MenWomen Sperm duct is blocked and prevents movement of sperm During the menstrual cycle the levels of mucus vary. Can lack the sperm ducts Women with CF have thick levels of mucus which can block the cervix so sperm cannot reach them.
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.