Alkaline tide refers to a condition, normally encountered after eating a meal, where during the production of

hydrochloric acid Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid Acid strength is the tendency of an acid, symbol ...

by the

parietal cells Parietal cells (also known as oxyntic cells) are epithelial cells in the stomach that secrete hydrochloric acid (HCl) and intrinsic factor. These cells are located in the gastric glands found in the lining of the fundus and body regions of the ...

in the stomach, the parietal cells secrete bicarbonate ions across their basolateral membranes and into the

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the c ...

, causing a temporary increase in blood pH. During hydrochloric acid secretion in the stomach, the gastric

parietal cell Parietal cells (also known as oxyntic cells) are epithelial cells in the stomach that secrete hydrochloric acid (HCl) and intrinsic factor. These cells are located in the gastric glands found in the lining of the fundus and body regions of the ...

s extract chloride anions, carbon dioxide, water and sodium cations from the blood plasma and in turn release bicarbonate back into the plasma after forming it from carbon dioxide and water constituents. This is to maintain the plasma's electrical balance, as the chloride anions have been extracted. The bicarbonate content causes the venous blood leaving the stomach to be more alkaline than the arterial blood delivered to it. The alkaline tide is neutralised by a secretion of H⁺into the blood during HCO₃⁻ secretion in the pancreas.

Postprandial Prandial relates to a meal. Postprandial (from post prandium) means after eating a meal, while preprandial is before a meal. Usages of postprandial The term ''postprandial'' is used in many contexts. Gastronomic or social Refers to activities p ...

(i.e., after a meal) alkaline tide lasts until the acids in food absorbed in the small intestine reunite with the bicarbonate that was produced when the food was in the stomach. Thus, alkaline tide is self-limited and normally lasts less than two hours. Postprandial alkaline tide has also been shown to be a causative agent of

calcium oxalate Calcium oxalate (in archaic terminology, oxalate of lime) is a calcium salt of oxalic acid with the chemical formula . It forms hydrates , where ''n'' varies from 1 to 3. Anhydrous and all hydrated forms are colorless or white. The monohydrate ...

urinary stones in cats, and potentially in other species.McGavin, MD., Zachary, JF. ''Pathologic Basis of Veterinary Disease, Fourth Edition, Mosby, 2007, pp. 680–686.'' A more pronounced alkaline tide results from

vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the Human nose, nose. Vomiting can be the result of ailments like Food-poisoning, foo ...

, which stimulates hyperactivity of gastric

s to replace lost stomach acid. Thus, protracted vomiting can result in

metabolic alkalosis Metabolic alkalosis is a metabolic condition in which the pH of tissue is elevated beyond the normal range (7.35–7.45). This is the result of decreased hydrogen ion concentration, leading to increased bicarbonate, or alternatively a direct resu ...

References

* Digestive system Metabolism Blood {{Digestive-stub