What is the function of hydrocloric acid in stomach?
Answers
Answer:
Hydrochloric acid, also called HCl, is a clear, highly corrosive liquid. HCl is one of the many chemicals released in our stomach when we eat a meal. The role of hydrochloric acid in the stomach, along with the other gastric juices, is to break down foods and cause the release of enzymes that further aid digestion. HCl also protects the body from illness by killing pathogens commonly found on foods.
Simple answer:- it helps in digestion of food.
Complex answer:-Gastric acid, gastric juice, or stomach acid, is a digestive fluid formed in the stomach and is composed of hydrochloric acid (HCl), potassium chloride (KCl), and sodium chloride (NaCl). The acid plays a key role in digestion of proteins, by activating digestive enzymes, and making ingested proteins unravel so that digestive enzymes break down the long chains of amino acids. Gastric acid is produced by cells in the lining of the stomach, which are coupled in feedback systems to increase acid production when needed. Other cells in the stomach produce bicarbonate, a base, to buffer the fluid, ensuring that it does not become too acidic. These cells also produce mucus, which forms a viscous physical barrier to prevent gastric acid from damaging the stomach. The pancreas further produces large amounts of bicarbonate and secretes bicarbonate through the pancreatic duct to the duodenum to completely neutralize any gastric acid that passes further down into the digestive tract.
The main constituent of gastric acid is hydrochloric acid which is produced by parietal cells (also called oxyntic cells) in the gastric glands in the stomach. Its secretion is a complex and relatively energetically expensive process. Parietal cells contain an extensive secretory network (called canaliculi) from which the hydrochloric acid is secreted into the lumen of the stomach. The pH of gastric acid is 1.5 to 3.5[1] in the human stomach lumen, the acidity being maintained by the proton pump H+/K+ ATPase. The parietal cell releases bicarbonate into the bloodstream in the process, which causes a temporary rise of pH in the blood, known as an alkaline tide.
The highly acidic environment in the stomach lumen causes proteins from food to lose their characteristic folded structure (or denature). This exposes the protein's peptide bonds. The gastric chief cells of the stomach secrete enzymes for protein breakdown (inactive pepsinogen, and in infancy rennin). Hydrochloric acid activates pepsinogen into the enzyme pepsin, which then helps digestion by breaking the bonds linking amino acids, a process known as proteolysis. In addition, many microorganisms have their growth inhibited by such an acidic environment, which is helpful to prevent infection.
Nutralization:-In the duodenum, gastric acid is neutralized by sodium bicarbonate. This also blocks gastric enzymes that have their optima in the acid range of pH. The secretion of sodium bicarbonate from the pancreas is stimulated by secretin. This polypeptide hormone gets activated and secreted from so-called S cells in the mucosa of the duodenum and jejunum when the pH in the duodenum falls below 4.5 to 5.0. The neutralization is described by the equation:
HCl + NaHCO3 → NaCl + H2CO3
The carbonic acid rapidly equilibrates with carbon dioxide and water through catalysis by carbonic anhydrase enzymes bound to the gut epithelial lining,[6] leading to a net release of carbon dioxide gas within the lumen associated with neutralisation. In the absorptive upper intestine, such as the duodenum, both the dissolved carbon dioxide and carbonic acid will tend to equilibrate with the blood, leading to most of the gas produced on neutralisation being exhaled through the lungs.