What is the main physiological defect in Cystic Fibrosis?

The main physiological defect in Cystic Fibrosis is the presence of defective chloride channels, specifically the cystic fibrosis transmembrane conductance regulator (CFTR) protein. This defect leads to abnormal movement of chloride ions and water across epithelial cell membranes. As a result, various secretions in the body, such as mucus, sweat, and digestive fluids, become thick and sticky instead of thin and watery.

This thickened mucus can obstruct airways in the lungs, leading to respiratory complications, and can also block ducts in the pancreas, impairing digestion and nutrient absorption. Additionally, sweat glands in individuals with Cystic Fibrosis may excrete an unusually high amount of salt, which can be a diagnostic indicator of the disease.

Understanding this primary defect is critical in managing Cystic Fibrosis, as treatments often focus on improving mucociliary clearance, optimizing nutrition, and addressing complications related to the dysfunction of various organs due to the altered ion transport. The other options mentioned do not accurately represent the underlying mechanism of Cystic Fibrosis and its systemic impact on the body.