The primary function of mucus is to protect the lungs from inhaled substances.
Mucus, specifically the airway surface liquid (ASL) in the respiratory system, serves as a crucial protective barrier. The provided reference states that the airway surface liquid (ASL), often referred to as mucus, is a thin layer of fluid covering the luminal surface of the airway. Its major function is to protect the lung through mucociliary clearance against foreign particles and chemicals entering the lung.
This protective role is achieved through a mechanism called mucociliary clearance.
How Mucociliary Clearance Protects the Lungs
Think of mucociliary clearance as the body's natural self-cleaning system for the airways.
- Trapping: The sticky nature of mucus allows it to effectively trap various inhaled irritants, including:
- Foreign Particles (like dust, pollen, bacteria, and viruses)
- Chemicals (such as pollutants and inhaled irritants)
- Transport: Tiny hair-like structures called cilia line the airways beneath the mucus layer. These cilia beat rhythmically in a coordinated wave.
- Removal: The coordinated beating of the cilia moves the mucus layer, along with the trapped particles and chemicals, upwards and outwards towards the throat. Once there, the mucus can be swallowed or coughed out, preventing these potentially harmful substances from reaching the delicate tissues deep within the lungs.
In essence, the function of mucus, supported by the action of cilia, is vital for maintaining lung health by continuously clearing the airways of unwanted materials.
