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What substances are found in gastric juice?

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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. — digestion The human digestive system as seen from the front.

Gastric juice is a variable mixture of several substances secreted by the gastric glands in the lining of the stomach. Its primary components include:

Water: Produced largely by parietal cells.12
Hydrochloric acid: Secreted by parietal cells, this acid creates a highly acidic environment (pH 1.5–2.5) necessary to activate digestive enzymes.342
Enzymes: These include pepsins, which are formed from pepsinogen secreted by zymogenic (chief) cells to initiate protein digestion. In some mammals, such as calves, gastric juice also contains rennin, which curdles milk.312
Electrolytes: The mixture contains sodium, potassium, calcium, phosphate, sulfate, and bicarbonate.2
Organic substances: This includes mucus, which coats the stomach lining to protect it from self-digestion, as well as various proteins.352
Intrinsic factor: A glycoprotein produced by parietal cells that is essential for vitamin B12 absorption and the maturation of red blood cells.1