A nasal mucous membrane with sufficient blood supply warms air
that is breathed in to a constant temperature, irrespective of climatic conditions. Its cells produce a secretion, which regulates the air to a moisture content of 80 to 85 %.
Cleaning and defence
The nasal secretion catches the tiniest of dirt particles and germs,
which are then transported by small hairs or cilia in the direction of
the throat. From there, they continue onwards into the stomach, where they are made harmless. Larger dirt particles are intercepted by nasal
hair at the entrance to the nose.