Hearing, seeing, and now smell as a function of seven stimulations
Home | What is the KOFH Educational Universal? | The KOFH Lotus Leaf Tutorial: How to utilize this concept in the academic classroom. | The Catalogue | Educational Products | Samples available | searching for better understanding since 1980 | The Physiological basis of the Mental Pattern | The Philosophical "Kant's" | The Underlying Neurology | Editorial Page | Talent? join us! | KOFH NEWSLETTER | Email homework aid | Freudian Bible Interpretation | email, or write

The Stero-Chemical Theory of Smell supposes that seven basic molecules are detected by the human nose. These seven molecules attach to neuron transmitters which have evolved such that seven kinds are geometrically available for receiving them.

Combinations of these seven, and varying proportions in kind, account for the vast multiplicity and acute differences in odors.

(Graphic links to more)

(Check this link for more on the sense of sight:)

. Most evidence supports a stereochemical theory of odor. Amoore et al. (in 1952) proposed that the sense of smell is based largely on the geometry of the odorant molecules. In this theory, there are a small number of primary odors that are detected by complementary receptor sites in the nose. Molecules that fit into a similar primary odor family do not necessarily have similar structural formulas, but they do have roughly the same molecular shape and size. Sometimes, charge is an additional important component. When a molecule of the correct size and shape fits into a complementary receptor site, an impulse is initiated (Figure 1). Complex odors result when a molecule fits into more than one kind of site (i.e., sideways into a wide receptor site and end-on into a narrow receptor site).

X-ray diffraction, infrared spectroscopy, and electron-beam probes have enabled scientists to build models of the seven primary odors.


Authors: Regina F. Frey and Maureen J. Donlin
Department of Chemistry, Washington University
St. Louis, MO

Click here for a link to the Science of 7 Smells