Inheritance and genetic screening (2.13–2.16) Flashcards
Why does CF cause sticky mucus?
- Mutation in the gene that codes for the CTFR proteins.
- The CTFR channel protein as it transports chloride ions out of the cell into the mucus which causes water to move into the mucus by osmosis.
How does cystic fibrosis affect the respiratory system?
- Cilia are unable to move the mucus towards the throat because its so thick and sticky.
- This means the mucus builds up in the airways.
- Some airways become completely blocked by the mucus and so gas exchange cannot happen.
- SA for available gas exchange is reduced, causing breathing difficulties.
- Prone to lung infections.
How does cystic fibrosis effect the digestive system?
The tube that connects the pancreas** to the **small intestine can become blocked preventing digestive enzymes from reaching the small intestine.
So they cannot digest food and absorb fewer nutrients.
Cysts form in the pancreas which inhibit the production of enzymes.
Mucus lining in the small intestine is so thick cannot absorb nutrients.
How does cystic fibrosis impact the reproductive system?
Men- tubes connecting the testicles to the penis are absent or blocked by mucus.
Women- thick cervical mucus can prevent sperm reaching the egg. Reducing the motility of sperm.
When is amniocentesis performed compared to CVS?
Amniocentesis- 15-20 weeks
CVS- 11-14 weeks
How is a sample taken for amniocentesis compared to CVS?
Amniocentesis- Sample of amniotic fluid via the abdomen using a fine needle.
CVS- Sample of cells from the chorionic villi (part of foetus) via the abdomen or the vagina
What is the risk of miscarriage or amniocentesis vs CVS?
Amniocentesis- 1%
CVS- 1-2%
How long do results take for amniocentesis compared to CVS?
Amniocentesis- results take 2-3 weeks for full but 2-3 days for most common
CVS- Initial results are available in a few days but more in-depth and detailed take 2 weeks or more.
