Although chloride is generally considered with sodium, with it functions in maintenance of extracellular fluid pH balance and osmolarity, the chloride ion also functions as activator for amylases and obviously is essential for the formation of gastric hydrochloric acid.
During digestion some of the chloride of the blood is used for the formation of hydrochloric acid in the gastric glands and is secreted into the stomach where is functions temporarily with the gastric enzymes and is then reabsorbed onto the blood stream with other nutrients.
Chloride is one of the major extracellular anions that helps maintain electrical neutrality with sodium. It is interesting that although chloride is generally transported across biological membranes by passive diffusion, in gastric and intestinal mucosa the chloride ion is actively transported.
Chloride ions are able to diffuse easily across plasma membranes, and their transport is linked closely to sodium movement, which also explains the indirect role of aldosterone in chloride regulation.
Chloride roles in extracellular fluid
