The Function of Mucus and Cilia in the Respiratory System

The primary function of mucus in the respiratory system is to trap inhaled particles, such as dust, bacteria, and other foreign substances, which can be harmful.
Mucus, produced by goblet cells, is released in the lining of the bronchi, the larger passageways in the lungs.
The mucus layer serves as a physical barrier and first line of defence against airborne pathogens and particles.
Cilia are tiny hair-like structures found along the airways. They move in wave-like motions.
The movement of the cilia moves the mucus and the trapped particles upwards towards the pharynx where it can be swallowed and destroyed by stomach acids.
This coordinated movement of cilia is often referred to as the ‘ciliary escalator’.
Cilia and mucus together provide an essential cleansing mechanism, preventing damage to the delicate tissues in the lungs.
Besides transporting mucus out of the lungs, cilia also help to humidify the air we breathe in, by spreading water and mucus over the airway surface.
Some harmful substances like cigarette smoke can damage or paralyse the cilia, reducing their efficiency to clear mucus, potentially leading to infections and respiratory diseases.
The constant movement of cilia and mucus out of the lungs allows us to breathe easily without even noticing all the work our bodies are doing to keep us healthy.

Remember the role of mucus and cilia is very important in keeping pathogens out of the body and maintaining respiratory health. It’s always worth revisiting these points as they are key to understanding the overall function of the respiratory system.

Also consider studying respiratory diseases, as they often connect directly to this topic providing real-world examples of what can happen when this system doesn’t function properly. For example, smoking-related diseases like Chronic Obstructive Pulmonary Disease (COPD) can be caused by damage to the cilia, reducing their ability to clear mucus.