Explain the role of the CFTR and Cl in the normal intestines and intestines with cholera.
Understand the Problem
The question is asking for an explanation of the roles of the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) and chloride ions (Cl) in normal intestines and in conditions affected by cholera. This involves discussing how these elements function in intestinal fluid secretion and absorption, and how their roles change during cholera infection, where there is an impairment in ion transport leading to diarrhea.
Answer
Cholera toxin causes continuous activation of CFTR, leading to excessive Cl- secretion and severe diarrhea.
Under normal conditions, CFTR regulates chloride secretion in the intestines, aiding in the balance of fluid. During cholera infection, the cholera toxin increases cAMP levels in intestinal cells, causing continuous activation of CFTR. This results in excessive Cl- secretion into the lumen, drawing water into the intestines and causing severe watery diarrhea.
Answer for screen readers
Under normal conditions, CFTR regulates chloride secretion in the intestines, aiding in the balance of fluid. During cholera infection, the cholera toxin increases cAMP levels in intestinal cells, causing continuous activation of CFTR. This results in excessive Cl- secretion into the lumen, drawing water into the intestines and causing severe watery diarrhea.
More Information
In normal intestines, CFTR helps maintain fluid balance by regulating Cl- transport. Cholera toxin disrupts this balance, leading to life-threatening dehydration if untreated.
Tips
A common mistake is misunderstanding the role of CFTR and mistaking its function for general ion transport rather than a regulated channel specifically for Cl-. Also, confusing cAMP's role as merely a secondary messenger without linking it to CFTR activation can lead to conceptual errors.
Sources
- Cholera toxin disrupts barrier function by inhibiting exocyst ... - NCBI - ncbi.nlm.nih.gov
- CFTR in cystic fibrosis and cholera: from membrane transport to ... - journals.physiology.org
- Basics of the CFTR Protein - Cystic Fibrosis Foundation - cff.org
