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Question: If you had too much acidic acid wouldn't it burn your stomach cells?
This is a very smart question!! In order to answer it, let's explore together the stomach as an organ. The stomach is a reservoir that holds ingested food and digest of the macronutrients like proteins and to some extent, fat. There are different types of cells in the gastric (stomach) wall that perform different functions. For instance, parietal cells secrete hydrochloric acid or gastric acid with a pH close to 2. The rate of gastric acid secretion varies significantly among individuals mainly due to the existent number of parietal cells. When acid secretion is stimulated, the parietal cell membrane (Cell envelope) recruits many hydrogen pumps (also known as proton pumps) that are usually dormant inside the cell.
Consequently, people who have more of these cells secrete additional acid because they have extra proton pumps compared to average individuals. Other factors involved in acid secretion are hormones like gastrin and histamine, which act on certain receptors to increase acid secretion upon ingestion of food.
Did you ever think about why we need acid in the stomach in the first place? Acid is needed to start protein and fat digestion in the stomach. Certain gastric enzymes are only active at a very low pH, basically when food enters the stomach. It is a fascinating protective mechanism that the stomach holds to protect itself from self-digestion. Another important function for acid is defense against food pathogens. The food we consume is never sterile. The gastric acid acts on most bacteria in food causing their complete breakdown; thus protecting us against a variety of infections.
Coming back to your question, gastric acid should not "burn" stomach cells as long as gastric cells and glads are functioning properly. Luckily, our gastric glands secrete an alkaline viscous substance called mucus that adheres to the stomach wall to protect it against digestive juices and to buffer acidity. The "burning" of stomach cells, which is know as an ulcer is related to the loss of the stomach's ability to defend itself against digestive enzymes and hydrochloric acid. However, most ulcer cases are due to an infection by acid-resistant bacteria called H. pylori; the details of this infection could be an excellent "Ask A Scientist" topic.
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