Final answer:
The mucous membranes in the nasal cavity function to trap dust, dirt, and pathogens, preventing their entry into the lungs, and to humidify the air to protect the respiratory tract.
Step-by-step explanation:
In addition to warming the air that enters the nose, the mucous membranes in the nasal cavity have several other functions. These include trapping particulate matter like dust, dirt, and microorganisms such as viruses and bacteria, thus preventing them from entering the lungs where they could cause damage or provoke an immune response. The mucus, along with cilia (tiny hair-like structures), work to move these trapped particles and pathogens towards the throat where they can be expelled from the body through mechanisms like sneezing or coughing.
The membranes are also responsible for humidifying the air, which helps to protect against the damaging effects of cold, dry air on the delicate tissues of the respiratory tract. This humidification process helps to ensure that the air reaching the lungs is at an appropriate temperature and moisture level, helping to reduce the risk of lung infections and preventing cell damage caused by inhospitable air conditions.