Significance of Chloride

SIGNIFICANCE OF CHLORIDE

Chloride, the major anion of the ECF, is found more in intersti-tial and lymph fluid compartments than in blood. Chloride is also contained in gastric and pancreatic juices and sweat. Sodium and chloride in water make up the composition of the ECF and assist in determining osmotic pressure.

The serum level of chloride reflects a change in dilution or concentration of the ECF and does so in direct proportion to sodium. Aldosterone secretion increases sodium reabsorption, thereby increasing chloride reabsorption. The choroid plexus, where cerebrospinal fluid forms in the brain, depends on sodium and chloride to attract water to form the fluid portion of the cerebrospinal fluid. Bicarbonate has an inverse relationship with chloride. As chloride moves from plasma into the red blood cells (called the chloride shift), bicarbonate moves back into the plasma. Hydrogen ions are formed, which then help to release oxygen from hemoglobin. When the level of one of these three electro-lytes (sodium, bicarbonate, or chloride) is disturbed, the other two will be affected as well.