How do mucus and cilia contribute to the body's infection defense?

Mucus and cilia play a crucial role in the body's defense against infections, particularly within the respiratory tract. Mucus acts as a sticky barrier that traps inhaled pathogens, such as bacteria, viruses, and dust particles, preventing them from reaching the lower respiratory system. Cilia, which are tiny hair-like structures lining the respiratory tract, work to move the mucus upwards towards the throat, where it can be either swallowed or expelled. This coordinated action is essential for clearing pathogens and debris from the respiratory passages, thereby helping to prevent infection.

The function of mucus and cilia is an integral part of the innate immune response, providing a physical and mechanical barrier against potential threats while also aiding in the effective clearance of harmful microorganisms from the airways.