Explain Mucous membranes - External Defence Mechanism

Mucous membranes: The digestive, urinary, genital and respiratory tracts open out at one or both ends. They do not have a direct communication with other parts of the body. The parasites, microbes present are not in the physiological interior of the body.  The mucous membranes in these tracts are treated as a part of external defence.  These membranes can resist entry of parasites, microbes into tissues.

Mucous traps the microorganism and immobilizes them.  How? Mucous, as you may know, is a clear, sticky substance and has glycoprotein and water. The microbes get trapped in this sticky fluid. Let us see what role the mucous has in the body systems and organs.