Foveolar cells or surface mucous cells are mucus-producing cells which go forward the inside of a stomach, protecting it from the corrosive bracket of gastric acid. These cells mark the gastric mucosa mucous neck cells are found in the necks of the gastric pits. The mucus-secreting cells of the stomach can be distinguished histologically from the intestinal goblet cells, another type of mucus-secreting cell.
The mucus presentation by these cells is extremely important, as it prevents the stomach from digesting itself. Parietal cells make-up potent hydrochloric acid, which damages cells. Gastric chief cells gain pepsinogen, which is activated by the acid to form pepsin. Pepsin is a protease that can digest and destruction stomach cells. To prevent these disastrous effects, mucus as well as bicarbonate ions HCO3− are secreted by the foveolar cells.
The mucus allows the acid at pH above 4 to penetrate lining, but below pH 4 i.e. when acid is more concentrated the acid cannot penetrate the mucus. This is called viscous fingering. Thus the foveolar cells can pump out a lot of acid, but acid once in the lumen of the stomach is prevented from returning.