Final answer:
The purpose of mucus in the nasal cavity is to trap pathogens, debris, and other particles, which the cilia then help to move toward the throat for expulsion or swallowing. This process helps prevent respiratory infections and is a key part of the body's immune defenses.
Step-by-step explanation:
The nasal cavity has mucous membranes that produce mucus, which serves several protective functions for the respiratory system. The main purpose of mucus is to trap pathogens and other potentially dangerous particles, preventing them from entering our lungs and causing infections. In addition to trapping pathogens, the mucus also traps debris. The cilia present in the nasal passages move the mucus towards the throat where it can be swallowed or expelled from the body. This defense mechanism is part of our body's innate immune system and is crucial for maintaining respiratory health, especially when exposed to infectious agents.
However, during an infection or in response to irritants, the mucous membranes can produce excess mucus, which can lead to congestion and the need to clear the nasal passages through sneezing or blowing one's nose.