When the olfactory, or scent-perceiving, organ is mentioned, the nose immediately comes to mind. However, very few are aware that as little as 5% of the nose is actually involved in the perception of scents. Gordon Shepherd, professor of neuroscience at Yale University emphasized the truth of this when he wrote, "we think that we smell with our noses, [but] this is a little like saying that we hear with our ear lobes."
The following pages shall examine that part of the nose concerned with scent perception. First, however, we should make a brief reference to the other 95%, which undertakes two major responsibilities on behalf of your respiratory system. The first of these is to warm and moisturize the air you inhale. The mucus layer covering the interior surface of the nose releases water vapor to moisture the air that enters. The large numbers of capillary vessels immediately beneath the mucus layer also warm the passing air, adapting it to the sensitive structure of the lungs. The mechanism in question resembles the air conditioning system that regulates the levels of temperature and humidity in buildings.
(Figure 2) A photograph of the micro-hairs known as cilia taken under the microscope
The second important function of the nose is to halt dust particles, bacteria and germs, thus acting as a screen to diseases that might otherwise reach the lungs. This is how this splendid security system functions: Harmful particles that enter with the air are trapped by the mucus layer. Then tiny hairs known as cilia go into action. (Figure 2) They propel mucus containing harmful substances at a speed of 1 centimeter (0.4 inches) per minute toward the pharynx, where it is either expelled by coughing or else destroyed by gastric acids.
These processes, here described in general terms, are in fact so exceedingly complex that the details of the mechanism by which millions of micro-hairs operate as a single entity has still not been fully understood. The mucus layer, mucus-producing cells and micro-hairs comprise a perfect chemical purification plant that works so flawlessly that it immediately identifies what is essential to the body and what is dangerous to it, and takes the necessary actions.
One truth is very apparent here: The air-conditioning, security and purification mechanisms in the nose are all examples of perfect engineering. It cannot possibly be imagined that circulatory, respiratory and digestive system cells agreed to cooperate among themselves and draw up plans like engineers. It is also impossible for the systems in question to have come about as the result of coincidences and to produce the aesthetically pleasing human face. It is revealed in verses that God created everything, from the Earth to the skies, with its perfection of design:
. . . Everything in the heavens and Earth belongs to Him. Everything is obedient to Him, the Originator of the heavens and Earth. When He decides on something, He just says to it, 'Be!' And it is. (Surat al-Baqara: 116- 7)