Lamina propria in the context of "Mucosa"

A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue known as the lamina propria. It is mostly of endodermal origin and is continuous with the skin at body openings such as the eyes, eyelids, ears, inside the nose, inside the mouth, lips, the genital areas, the urethral opening and the anus. Some mucous membranes secrete mucus, a thick protective fluid. The function of the membrane is to stop pathogens and dirt from entering the body and to prevent bodily tissues from becoming dehydrated.

Amphibians, fish, snails, slugs, and some other invertebrates also produce external mucus from their epidermis as protection against pathogens, to help in movement, and to line fish gills. Plants produce a similar substance called mucilage that is also produced by some microorganisms.

The gastric mucosa is the mucous membrane layer that lines the entire stomach. The mucus is secreted by gastric glands, and surface mucous cells in the mucosa to protect the stomach wall from harmful gastric acid, and from digestive enzymes that may start to digest the tissue of the wall. Mucus from the glands is mainly secreted by pyloric glands in the lower region of the stomach, and by a smaller amount in the parietal glands in the body and fundus of the stomach.

The mucosa is studded with millions of gastric pits, which the gastric glands empty into. In humans, it is about one millimetre thick, and its surface is smooth, and soft. It consists of simple secretory columnar epithelium, an underlying supportive layer of loose connective tissue called the lamina propria, and the muscularis mucosae, a thin layer of muscle that separates the mucosa from the underlying submucosa. The gastric mucosa serves as a gastric barrier, reinforced by tight junctions between the epithelial cells.

The oral mucosa is the mucous membrane lining the inside of the mouth. It comprises stratified squamous epithelium, termed "oral epithelium", and an underlying connective tissue termed lamina propria. The oral cavity has sometimes been described as a mirror that reflects the health of the individual. Changes indicative of disease are seen as alterations in the oral mucosa lining the mouth, which can reveal systemic conditions, such as diabetes or vitamin deficiency, or the local effects of chronic tobacco or alcohol use.The oral mucosa tends to heal faster and with less scar formation compared to the skin. The underlying mechanism remains unknown, but research suggests that extracellular vesicles might be involved.