What Are the Functions of Stomach Acid?

What is it?

Acid solution mainly constituting hydrochloric acid secreting in the stomach is known as stomach acid or gastric acid. Parietal cells in the stomach produce this acid. The secretion takes place inside the lumen of the stomach through a network in the parietal cells called ‘canaliculi’. The pH of gastric acid varies between 2 and 3.

Functions

Stomach acid breaks down the food we eat and facilitates digestion. This the acid does by producing a digestive enzyme called pepsin that by the process of proteolysis breaks the amino acid bonds. The gastric acid by maintaining an acidic environment in the stomach protects it from infection from microorganisms. The secretion starts from the time we see food and start eating with the smell and taste acting as stimulators.

Most of the secretions take place when the ingested food goes to the stomach. Proteins produced in the digestive process further stimulate production of gastric acid. Some more secretion of the acid takes place when the partially digested food reaches the small intestine from the stomach. The hormone ‘gastrin’ stimulates production of stomach acid by the parietal cell and hence the acid is also called gastric acid. The process also stimulates release of histamine which in turn regulates stomach acid secretion. Sodium bicarbonate secreting from the pancreas being alkaline neutralizes the acid to keep it to the optimum level by breaking it down into water.

Diseases

Inadequate secretion of stomach acid can lead to infections of the digestive tract since the acid acts as disinfectant against infecting microorganisms. On the other hand, excess secretion can cause ulcer of the stomach by damaging the esophagus lining. The condition is called gastric ulcer. The acidic environment in the stomach is however regulated by a bicarbonate solution produced by and secreted from epithelial cells protecting the mucosa from injury. It also ensures that the gastric acid does not digest the stomach itself.