Page 22 - The Miracles of Smell and Taste

20

Engineering in the Nose

When the olfactory, or scent-perceiving, organ is mentioned, the nose
immediately comes to mind. However, very few are aware that as little as
3
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.” 4
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 mech-
anism in question resembles the air conditioning system that reg-
ulates the levels of temperature and humidity in buildings.
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 en-
ter with the air are trapped by the mu-
cus layer. Then tiny hairs known as cil-
ia go into action. (Figure 2) They pro-