Page 128 - The Miracles of Smell and Taste

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Electrical Current in
the Perception Region
Radioactive
Clean air
Terminal Reference source
Link scre sectio High-
current
leve
Ionized
particle
Radioactive
Control substance
Smoke
unit or
proc- Plastic Low
current
essor casing lev
Alarm in-
dicator Perception Perception area Smoke
clinging
area-casing to particle

(Figure 20)
The picture shows the comparatively complex structure of a smoke detector.
The system in scent perception cells, however, is far more complex than
this.

to the scent-receptor cells in the nose. You have already seen how the elec-
trical charge in the receptor cell changes as a result of complex processes,
and how a specific message thus emerges. The mechanism in a smoke de-
tector is a rather primitive model of the perception system in the scent-re-

ceptor cells. Also, the difference between a fire detector and the human
nose is far greater than that between a spacecraft and an oxcart.

The Electronic Nose

The human olfactory system can distinguish some 10,000 different
odors. A professional in the perfumery business is able to smell a perfume
that has a 100 different odorants in it, and list the ingredients. 106 This su-
perior creation in the human nose has encouraged numerous scientists to

The Miracles of Smell and
Taste