Stomach mucosa

General information

Seen from the outside, the stomach looks like a tube that has been dilated. It can let the food pass by the shortest way or store it for a while. If you look inside the stomach (gastroscopy), e.g. with the help of an endoscope, you can see a coarse folding of the mucous membrane. Most of the folds run in the direction of the food pathway and thus form the so-called gastric pathway, on which liquids can pass so quickly.

Structure of the stomach and mucous membrane

However, the fine structure of the stomach lining is particularly important for the tasks and functions of the stomach. More on this topic: Tasks of the stomach All organs of the digestive tract through which food travels, the so-called hollow organs, are very similar in their wall structure. All of them consist – from the inside out – of a mucous membrane, a surrounding muscle layer and a connective tissue skin that borders on the abdominal cavity.

The actual stomach mucosa is in turn divided into three layers. Starting from the inside, these are:

  • The lamina epithelialis, which contains mucus- and acid-producing cells
  • The lamina propria, in which glands are present, whose function and structure varies depending on their location in the stomach, and
  • The lamina muscularis, a muscle layer that helps to stretch and contract the other two layers.

The actual glands in the lamina propria are close to the next outer layer, the lamina muscularis. There are cells that produce hormones, and cells that produce enzymes that begin to break down food components.

In the glandular neck, which conducts the secretion into the stomach, there are also cells that release hydrochloric acid, which is responsible for the acidic environment in the stomach, and cells that produce a neutralizing mucus. The cells of the superficial mucosa, the lamina epithelialis, also produce a tough and fatty mucus that covers the mucosa and thus protects it from the aggressive acid. The stomach mucosa shows differences in structure and function depending on its location.

At the entrance to the stomach, for example, a lot of mucus is produced, as well as lysozyme, a defence against bacteria. The main part of the stomach is where most of the acid production and thus the actual digestion takes place. Digestive enzymes are also added here, which break down fats, for example, to make the process even more effective and targeted.

A lot of mucus is again produced at the exit of the stomach, which makes the food pulp less acidic and thus already prepares it for the further route through the intestine, where a rather alkaline environment prevails. After the esophagus, food enters the stomach, which is one of the first stages of digestion. Its task is not to extract individual substances from the food, but rather to make these substances more easily accessible for the subsequent digestive steps.

In addition, possible pathogens, which are inevitably ingested in a certain number with food, should be rendered harmless. The stomach mucosa does this by excreting lysozyme (see above) and by producing hydrochloric acid, which ensures a pH value of 2 inside the stomach and thus a very acidic environment. Due to the tough mucous layer, which acts as a protective coat, the cells of the stomach mucosa create a neutral environment (pH=7) and thus protect themselves from the damaging effect of the acid.

This balance is susceptible to disturbances. For example, inflammation or alcohol consumption can lead to an excess of acid and thus to damage to the stomach lining.