Page 40 - The Miracles of Smell and Taste

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(Figure 9)
The structure of a scent re-
ceptor. The structure con-
sisting of seven spirals, in
the upper part of the dia-
gram, is the section on the
receptor cell membrane.
The units at the bottom of
gamma unit
the diagram constitute the
part remaining inside the
beta unit
cell.
alpha unit

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inch). The difference between these scent hairs and similar ones in oth-
er regions of the nose is that the former move and possess scent receptors.

(Figure 9) In contrast to the other cilia in the body, the olfactory micro-
hairs are entirely independent structures. They assume the role of a skel-
eton for the receptors. Close inspection shows the most productive design
for the micro-hairs, with a wide area for contact between scent molecules
and receptors being squeezed into a very small region. In addition, latest
research has revealed that each olfactory cell contains just one of a thou-
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sand different types of scent receptor, as we’ll consider later, in greater
detail.
Though the term cilia or micro-hairs may suggest very simple struc-
tures, the fact is that these terms describe only the shape of the structures
in question. In fact, olfactory micro-hairs possess an incomparable and ex-

traordinary communications technology. Scent molecules that dissolve in
the mucus combine with special receptors on the scent micro-hairs. The
relationship between the scent molecule and the receptor resembles that
between a lock and key. As a result of molecular details that have not yet

The Miracles of Smell and
Taste