What is the main function of mucus in the respiratory system?

Mucus serves a crucial role in the respiratory system primarily by trapping particles and pathogens. This sticky substance is produced by goblet cells located in the lining of the airways. Its primary function is to capture dust, dirt, allergens, and microorganisms that are inhaled into the respiratory tract. By trapping these unwanted particles, mucus prevents them from reaching the delicate tissues of the lungs, which could lead to infections and respiratory problems.

Additionally, mucus helps to keep the airway surfaces moist, which is vital for the proper functioning of the respiratory system. The presence of mucus is an important part of the immune defense, and it facilitates the movement of trapped particles towards the throat, where they can be swallowed or expelled. This protective mechanism is essential for maintaining respiratory health, particularly in environments with high levels of pollutants or pathogens.

In contrast, while other choices address different aspects of respiration, they do not accurately capture the primary function of mucus within the respiratory system.