Question

What is the role of acid in our stomach?

Answer 1

The stomach acid or gastric acid is a digestive fluid formed inside the stomach lining. The pH of stomach acid varies from $1 - 3$. The mainly formed stomach acid is the hydrochloric acid. It has a major role during the process of digestion. The cells in the stomach lining also produce mucus which acts as a barrier to prevent the acid from damaging the stomach.

Complete explanation:
Hydrochloric acid (HCl) helps in digestion by breaking down the food particles and making cells absorb nutrients such as protein. They also kill any harmful bacteria present in the food. HCl acid also facilitates the function of other enzymes during digestion. It activates the pepsinogen enzyme required to digest proteins in food. The pepsinogen along with HCl break down the long chain of amino acids of proteins.
The HCl acid is produced by parietal cells in the gastric glands of the stomach. The secretion of acid is a complex and energetically expensive process. Parietal cells contain a large, secretory network called canaliculi through which the hydrochloric acid is secreted into the lumen of the stomach. The pH of acid in stomach lumen is maintained by the proton pump .$\dfrac{{{H^ + }}}{{{K^ + }}}$. ATPase.
Their production is regulated by both the autonomic nervous system and hormones. When the stomach acid is not needed it is neutralized by bicarbonate in the duodenum. The bicarbonate secretion is stimulated by hormone secretion produced by mucosa of the duodenum and jejunum.

Note:
When there is no production of hydrochloric acid in the stomach, the proper digestion of food will not occur. It’ll also hinder the iron absorption process. Protein breakdown and absorption will also be inhibited. The stomach is designed in a way to produce acid when food is consumed and stop after digestion. Increased production of acid also leads to health problems such as acidity, stomach ulcers, stomach pain etc.