Clinical Definition

The mucous membranes, or mucosae, are moist tissues that line parts of the nose, mouth, lungs and urinary and digestive tracts. Special cells in the mucous membranes release mucus.

In Our Own Words

Mucous membranes, also called mucosae, are the moist tissue layers that line many structures and cavities in the body, including the nose, mouth, lungs, urinary and digestive tracts. Some mucous membranes are specialized for the part of the body in which they are found. For example, the gastric mucosa secretes thick mucus lubricating the food and protecting the cells in the stomach lining from digestion. Mucus membranes throughout the body can also be important in infections and immunity.