Chloride is the most plentiful extracellular electrolyte, with an
extracellular concentration 26 times that of its intracellular
concentration.
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
