Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Sense of smell
Name: matkru
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: Around 1993


Question:
How does the nose distinguish between different smells? What exactly is it smelling anyway and is there any way to reproduce this?



Replies:
The nose distinguishes between different smells via the nasal epithelium at the top of you nasal pharynx. That is a delicate membrane innervated by many nerve cells. Each nerve cell has many proteins embedded in its cell membrane. These proteins have complimentary shapes to certain chemical groups that elicit scents. When an odorant molecule binds to one of these proteins, the cell depolarizes (due to a second messenger system in the membrane). This depolarization propagates back to the part of the brain called the olfactory bulb, below the forebrain. There the information from different cells is sorted out and sent to other brain structures, and the subjective sense of "smell" is elicited. Distinguishing between different odors is possibly accomplished by comparing different inputs from nerve cells with different protein receptors in them, or by "labeled lines" of neurons with a mix of proteins in them that are complimentary to a mix of odorant molecules that make up a scent. I know of know mechanical process that approximates smell by spectroscopy can distinguish different molecules The answer I have given is for vertebrates but invertebrates and plants can also smell, although by different mechanisms. Smelling in general is the subjective sensation experienced when one's olfactory system detects a scent; it can not be approximated by any mechanical process that I am aware of, although spectroscopy can be used to distinguish between chemical milieus.

Jim Murray



Click here to return to the Biology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory