Corpus: Lamina propria

The lamina propria is a thin, subepithelial connective tissue layer in hollow organs that is located directly below the basement membrane of the lining epithelium. It is not an independent layer in the wall structure of hollow organs, but is part of the tunica mucosa alongside the lamina epithelialis mucosae.

A distinction can be made depending on the epithelial form present:

• Lamina propria mucosae: Lamina propria of the mucosa
• Lamina propria serosae: lamina propria of the serosa
• Lamina propria synovialis: lamina propria of the synovium

The lamina propria contains fibrocytes, blood vessels, lymphatic vessels, nerves and fibres, among other things. In some mucous membranes, glands are also found here, e.g. in the oral mucosa, stomach or duodenum.

In the digestive tract there is a thin layer of smooth muscle under the lamina propria, the lamina muscularis mucosae, which is also a component of the tunica mucosa.

As the epithelium itself has no blood vessels of its own, it is supplied by diffusion via the vessels of the lamina propria.

In the course of their growth, carcinomas penetrate the basement membrane and grow into the lamina propria. From here, metastasis can take place via the blood and lymph vessels.