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How does the human stomach protect itself from its own acid?

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Diagram of the human digestive system viewed from the front, showing and labeling organs including the mouth, teeth, tongue, salivary glands, pharynx, esophagus, liver, stomach, gallbladder, pancreas, large intestine, small intestine, appendix, rectum, and anus. — human digestive system The human digestive system as seen from the front.

The human stomach protects itself from its own acid through a robust defense mechanism involving mucus secretion. The gastric glands in the stomach lining produce a thick layer of mucus that coats the inner surface. This mucus acts as a physical barrier, preventing the highly acidic gastric juice and protein-digesting enzymes from reaching and damaging the stomach's own tissues.123

Furthermore, the mucus layer traps alkaline fluid secreted from the underlying mucosa, creating a pH gradient. This means the mucus layer is neutral at the epithelial surface and becomes more acidic towards the stomach's lumen. The stomach lining also secretes hydrochloric acid, which is strong enough to kill many ingested microbes.345