Why doesn’t stomach acid destroy tissues?

The stomach contains hydrochloric acid, a highly corrosive chemical compound that can dissolve some metals. Its purpose is to create an ideal environment for digestive enzymes to break down food and kill bacteria. However, although very strong, this acid does not destroy tissue in the body, according to IFL Science.

Thanks to the large amount of mucus, tissues are not destroyed by acid. That mucus is made up of large glycoproteins called mucins that have sugar molecules attached to them such as N-acetylglucosamine and sialic acid, which help the mucus become slippery and not be digested. Mucin clumps together to form two forms of mucus in the stomach: one is thick and sticky and sticks firmly to the stomach wall, the other is a looser, gel-like type that slides around. It is this looser layer where the beneficial bacteria that make up the intestinal microflora live.

If given the chance, stomach acid will destroy the body’s own tissues. It is released by the walls nestled within the longitudinal folds of the stomach lining. When sprayed, the pH of the acid is only 0.8. Acid mixed with other stomach secretions causes the pH to increase to 1 – 3, according to the Institute of Human Anatomy. All mucus acts as a physical barrier that prevents acid from separating from the stomach wall. Not only does it become a barrier, mucus also contains bicarbonate that can neutralize acids. That’s why many heartburn medications contain bicarbonate because of its effect in treating stomach acid that refluxes into the esophagus.

However, some parasites and bacteria can weaken the mucus barrier. When this happens, bacteria can enter the stomach tissue, contributing to gastritis and many other diseases. Some of the most serious ulcers can cause bleeding while forming at the site of blood vessels. If too severe, the ulcer can perforate the stomach when acid leaks into the abdomen. This serious complication of gastric and duodenal ulcers is an emergency.