Final answer:
Mucous membranes act as a mechanical barrier to prevent the entry of pathogens. They secrete mucus to trap pathogens and have cilia to sweep them towards body openings for removal.
Step-by-step explanation:
Mucous membranes play a crucial role in the cycle of infection. They are the linings of the respiratory, gastrointestinal, genitourinary tracts, and other body openings. These membranes provide a mechanical barrier to prevent the entry of pathogens into the body. Mucous membranes secrete mucus, a slimy substance that traps pathogens and other particles. Additionally, they have hair-like cilia that sweep mucus and trapped pathogens towards body openings for removal.