Irregularities in the connective tissue surface, such as papillae found in the tongue, increase the area of contact of the lamina propria and the epithelium.

The connective tissue and architecture of the lamina propria is very compressible and elastic, this can be seen in organs that require expansion such as the bladder.

[7] The lamina propria may also be rich in vascular networks, lymphatic vessels, elastic fibers, and smooth muscle fascicles from the muscularis mucosae.

[10] The lamina propria’s richness in macrophages and lymphoid cells makes it a key place for immune responses to occur.

It forms part of the barrier that protects internal tissues from external pathogenic microorganisms, especially from the gastrointestinal tract.

[13] As soon as the tumors breach the basement membrane and reach the lamina propria, they are exposed to lymphatics which may increase the rate of metastasis and cancer progression.

The lamina propria macrophages when under much stress release pro-inflammatory signals that may lead to increased probability of developing cancer.