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The top part of the nose has millions of smell
receptors, but there are only 10 000 different types of receptor, which is not enough to
define every smell to which we may be exposed.
Senses and behaviour
The brain recognises smells by examining the particular combination
of receptors stimulated on each occasion. This website presents a diagram of the olfactory
system in human beings.
During respiration we inhale air and with it a host of aromatic
substances. The information on smell is received and starts to be processed when these
aromatic substances reach the top of the nasal cavity, where the olfactory epithelium is
located.
Respiratory system
You can find the structure, together with images of the nose and
nasal cavity, in the section «Nose and Nasal Cavity of Respiratory Organs of the Head and
Neck».
As well as the sense of smell, do we have the ability to sense certain
chemical signals emitted by those around us without being aware of it? Scientists have
recently attempted to answer this question.
The sixth sense
It is believed, with growing certainty, that we, like some mammals
and insects, possess a system of receptor cells in the nose which enables us to receive
social and sexual information from members of our own species. Here you will find
extremely interesting information on the subject.
And, what exactly are we referring to when we talk about this sixth
sense? Are we referring to visual or olfactory signals that are subtle and difficult to be
specific about, or does a sixth window on the world really exist? The answer appears to be
the latter: it has been shown that in human beings a sense system exists, traditionally
described as non-functional, which is sensitive to certain transmittable substances
present in the human skin.
Perfumes and the sixth sense
The working of the sixth sense appears to be closely related to
communication by pheromones, discovered in insects and mammals. This sense system has no
name as yet, but does have its own organ: this is the vomeronasal organ. Go here for more information on this
sense organ.
Sense experiences are unique for each individual, although we may
share smells, sights and sounds with those near to us at the time of the experience.
RealAroma
Thanks to the Internet we can share sights and sounds at a distance...
and also smells. RealAroma shows you how.
For years attempts have been made to emulate the enormous sensorial
repertoire of the smell receptors and create an artificial nose. Beyond any purely
technological interest, this has numerous applications: chemical analysis, environmental
control emissions, detection of narcotics and explosives.
Smell
A group at the California Institute of Technology explain their
project.
