Mukosal

Mukosal is an adjective relating to mucosa, the moist mucous membrane that lines many cavities and tubes that connect to the outside of the body. Mucosa covers structures such as the respiratory, gastrointestinal, and urogenital tracts, the oral cavity, and portions of the eye. The term is used in medicine and anatomy to distinguish the mucosal lining from other tissues.

Anatomy and tissue composition: A mucosa typically consists of an epithelium, a connective tissue layer called the lamina propria, and, in many regions, a thin layer of smooth muscle called the muscularis mucosae. The epithelial type varies by site: ciliated pseudostratified or simple columnar in the respiratory and digestive tracts, and stratified squamous in the mouth, esophagus, and certain parts of the vagina. Goblet cells and, in some regions, glands secrete mucus that lubricates and helps trap pathogens.

Function and immunity: The mucosa serves as a barrier to infection, participates in selective absorption and secretion, and contains immune components such as secretory immunoglobulin A and organized mucosa-associated lymphoid tissue (MALT), providing localized immune responses.

Clinical relevance: Mucosal integrity is critical for health; diseases may involve inflammation, ulceration, infection, or atrophy of mucosal surfaces, including gastritis, inflammatory bowel disease, rhinitis, and celiac disease. Treatments may target healing of the mucosa or delivery of vaccines across mucosal surfaces.

Etymology and overview: The term derives from Latin mucus and membrane. See also mucus and mucosa-associated lymphoid tissue.