How does mucus trap pathogens in the respiratory tract?

Mucus in the respiratory tract traps pathogens by capturing them in its sticky, gel-like substance.

Mucus is a viscous, gel-like substance that is produced by the goblet cells in the lining of the respiratory tract. It plays a crucial role in our body's defence mechanism against pathogens, which are harmful microorganisms such as bacteria, viruses, and fungi. The primary function of mucus is to trap these pathogens and prevent them from entering our body and causing infections.

The mucus layer in the respiratory tract is constantly moving, propelled by tiny hair-like structures called cilia. These cilia beat in a coordinated manner, creating a wave-like motion that moves the mucus, along with the trapped pathogens, towards the throat. From there, it can be swallowed into the stomach where the acidic environment destroys the pathogens, or it can be expelled from the body through coughing or sneezing.

The mucus also contains various antimicrobial substances, such as lysozyme and immunoglobulins. Lysozyme is an enzyme that can break down the cell walls of bacteria, leading to their destruction. Immunoglobulins, on the other hand, are antibodies that can bind to specific pathogens, neutralising them and marking them for destruction by other immune cells.

In addition to trapping pathogens, the mucus also helps to keep the respiratory tract moist and prevents it from drying out. This is important as dryness can lead to damage and inflammation of the respiratory tract, making it more susceptible to infections.

In summary, mucus in the respiratory tract acts as a physical barrier against pathogens, trapping them in its sticky substance and moving them out of the body. It also contains antimicrobial substances that can directly kill or neutralise the pathogens.