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> March 10, 2000:
Hour Two: Smell
| Take a deep breath. Smell anything? Maybe you're getting a few whiffs of early-spring air. Maybe you're dealing with the garlic-anchovy pizza on your co-worker's desk. Or maybe you're catching molecules of perfume from the woman next to you in the elevator. So how does the sense of smell work? What happens when it doesn't work right? And how are efforts to develop odor-related technology progressing? |  | On one level, the workings of your sniffer are pretty straightforward. Odor molecules have a specific shape. When they enter the nose, if those shapes match up with surface proteins on odor-sensing neurons (about 10 million of them, with over 1,000 configurations) the neuron fires. But at levels beyond that, it gets much more complicated, involving subtle mixes of chemicals, the ways that proteins bind together, how long they stick to receptors, genetics, and more.
"Not smelling" may seem like a joke, but 2-3 percent of the population is "anosmic" -- having little or no sense of smell. About 15% of the population has some form of "odor blindness" -- not being able to smell certain things that other people can smell. And since about 90% of what people perceive as "taste" is actually produced by smell (hold your nose and eat a piece of chocolate - it doesn't taste very chocolatey at all!) a lack of ability to smell can become a real quality-of-life issue.
 | Several companies are developing "artificial noses," sensors that can identify odor components on the fly. Most of these are designed for some type of quality-control monitoring or environmental sampling, such as making sure that fish shipments are fresh or that oil refineries aren't emitting compounds they shouldn't. A few inventors are working on using an artificial nose for medical diagnoses, using it to sense faint tell-tale scents given off by certain bacteria, for example. And there's even an effort afoot to create a sort of Smell-o-Vision for the Internet Age - an artificial odor generator called DigiScents.
Join us on this hour of Science Friday as we find out what science knows about noses! |
Guests:
Alan Hirsch, M.D.
Neurological Director
Smell and Taste Treatment and Research Foundation
Chicago, Illinois
Stuart Firestein
Associate Professor, Biology
Columbia University
New York, New York
Nathan Lewis
Professor, Chemistry
California Institute of Technology
Pasadena, California
Books/Articles Discussed: Related Links:
MEDLINEplus: Taste and Smell Disorders Monell Chemical Senses Center Association for Chemoreception Sciences NIDCD Health Information . Smell and Taste Newton's Apple Teacher's Guide:Taste And Smell Howard Hughes Medical Institute: Seeing, Hearing and Smelling the World
Neuroscience
for Kids - The Senses
DigiScents - Digital Scent Technology That Gives Your Computer The Sense Of Smell
Wired: You've Got Smell!
This segment produced by:
Karin Vergoth
Web producer:
Charles Bergquist |