Originally Posted by
Jordan Feigenbaum
The stomach has a variety of different cells making up its epithelial lining, i.e. what interacts with the contents of the stomach, this "epithelial layer" lines the stomach's mucosa. There are what's known as "mucus neck cells", contained within the glands of the stomach's mucosa. These cells produce mucus at a high enough rate to create an "unstirred" layer of mucus that protects the epithelium from direct contact with the acid of the stomach, which is produced by the parietal cells of the stomach.
Certain situations, like taking NSAIDs for instance, will decrease the production of mucus by the mucus-neck cells and thus predispose a person to acid damage of the mucosa, an ulcer. Patients who are losing lots of blood or who receive a large surface area burn can also see acid-induced damage because in these scenarios there is less blood flow (via hemhorrhage or similar) to the stomach and thus less acid is able to be carried away.
This is like a 10,000 ft view- for the record.