How Is the Nose Able to Smell?
Smells, or odors, are caused by tiny particles called molecules, which are constantly emitted by the many different substances around us. These odor molecules spread rapidly, in the form of gases and vapors.
You smell by means of a special group of nerve cells located in the back of your nose. When you sniff, a flower, its vapors stimulate the smell nerves in your nose. The nerve cells send a message to the brain, and the brain recognizes the fragrance. If you hold your nose, odors can’t reach the sense-of-smell nerve cells.
The nose allows you to make scents of what’s going on in the world around you, the nose lets you figure out what’s happening by smelling. It does this with help from many parts hidden deep inside your nasal cavity and head.
Up on the roof of the nasal cavity is the olfactory epithelium which contains special receptors that are sensitive to odor molecules that travel through the air. These receptors are very small — there are about 10 million of them in your nose!
There are hundreds of different odor receptors, each with the ability to sense certain odor molecules. Research has shown that an odor can stimulate several different kinds of receptors. The brain interprets the combination of receptors to recognize any one of about ten thousand different smells.