MUCUS AND THE OVER-PRODUCTION OF IT

The thick slimy fluid secreted by mucous membranes is called mucus. Mucus moistens, lubricates and protects those parts of the body lined by mucous membrane, such as the digestive, respiratory and genital tracts and eyelids. Mucus eases swallowing, lubricates food as it passes through the digestive tract, prevents stomach acid from damaging the stomach wall and prevents enzymes from digesting the intestine.

In the respiratory tract, mucus moistens inhaled air and traps smoke and other foreign particles in the airways (to keep them out of the lungs). So as you can see, mucus is essential for the smooth running of the body. For the purpose of this section we will only concentrate on the mucus produced by the respiratory system.

Mucus is a lubricant and contains specialized proteins to keep the surface cells of mucous membranes alive. The whole of the respiratory system depends on membranes covered with tiny hairs (cilia), which move mucus along with the air that we breathe. The vocal cords are not hairy, so we tend to cough to shift unwanted mucus. However, there is a 'mucus' blanket or layer along the length of the vocal cords, necessary for vocal cord vibration. If this layer becomes dry, which can happen when we are unwell, the cords cannot vibrate.

The sinuses, which act as the body's air conditioning system by moistening, warming and filtering the air, are also covered with a layer of mucus. This has a protective function, helping to remove particles of debris, as well as retaining moisture and transferring heat.