Chloride Secretion and Cystic Fibrosis Mechanisms

Chloride secretion

Process of Cl- moving across epithelial cells.

Tight junctions

Structures dividing epithelial cells into domains.

Na pump

Establishes ion gradients for cell function.

NaK2Cl symporter

Uses Na gradient to accumulate Cl- actively.

Passive diffusion

Movement of Cl- through ion channels.

Basolateral Na-pump

Exchanges Na+ for K+ in epithelial cells.

Paracellular fluxes

Movement of Na and water alongside Cl-.

Rate-limiting step

Cl- channel opening controls Cl- secretion rate.

CFTR

Cystic Fibrosis Transmembrane Conductance Regulator, a Cl- channel.

Secretory diarrhea

Excessive fluid secretion in intestines, causing diarrhea.

Endogenous secretagogues

Substances stimulating secretion from cells.

Enterotoxins

Bacterial toxins activating CFTR, causing diarrhea.

Adenylate cyclase

Enzyme activated by enterotoxins, increasing CFTR activity.

Cystic fibrosis

Genetic disorder affecting chloride transport in cells.

Autosomal recessive

Inheritance pattern requiring two copies of mutated gene.

Carrier

Individual with one mutated gene, no symptoms.

Disease frequency

Incidence of CF varies by ethnic group.

Median survival

Average lifespan of CF patients is 38 years.

Chest percussion

Technique to clear lung secretions in CF patients.

Pancreatic enzyme replacement

Treatment for digestive issues in CF patients.

Salty sweat

Characteristic of CF due to NaCl reabsorption failure.

Isotonic secretion

Initial fluid secretion by acinar cells in sweat glands.

Hypotonic solution

Fluid with lower solute concentration after NaCl reabsorption.

Membrane potential

Electrical charge difference across cell membranes.