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What causes cystic fibrosis?

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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 systems 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 too 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 thickens Cl- Na+ H2O mucus 2 apical membrane 5 CFTR channel closed Na+ channel open H2O pump 1 basal membrane 4 3 tissue fluid H2O Cl- Na+

4 When there is too little water in the mucus
Water is drawn out of the mucus and it becomes less sticky Cl- Na+ Na+ mucus 3 2 4 apical membrane Na+ channel closed CFTR channel open H2O The CFTR somehow blocks the sodium channels Cl- 1 H2O basal membrane 5 pump tissue fluid H2O Na+

5 With cystic fibrosis X The mucus becomes very thick and sticky mucus
Cl- Na+ H2O mucus 1 2 3 X apical membrane CFTR non- functional The CFTR protein cannot block the sodium channels so they are always open Water drawn out by osmosis Na+ channel open H2O basal membrane H2O tissue fluid Cl-

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 energy Infections - as bacteria are trapped in mucus

7 How does cystic fibrosis affect the reproductive systems?
Men Women 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.

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.

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