What is a mucous membrane?

A mucous membrane is accurately defined as a mucus-secreting membrane that lines body cavities and passages that communicate with the exterior, such as the respiratory, digestive, and urogenital tracts. This type of membrane plays a crucial role in the body's defenses; it produces mucus, which serves to both trap pathogens and keep the membranes moist, aiding in protection and facilitating the movement of materials across the membranes.

The presence of mucus helps prevent desiccation (drying out) and provides a barrier to pathogens, contributing to the immune response. Moreover, mucous membranes are vital in absorption and secretion functions throughout various body systems. The definition emphasizes the unique characteristic of these membranes in their connectivity to external environments, distinguishing them from other types of membranes in the body.