Smell

Smell

The sense of smell brings us into harmony with nature, warns us of dangers and sharpens our awareness of other people, places and things.
It helps us to respond to those we meet, can influence our mood, how long we stay in a room, who we talk to and who we want to see again.
The nose allows us to make scents of what's going on in the world around us.

Baby's recognize the smell of their mother immediately. It is the first contact of the baby with the outside world. A baby knows who his own mother is just by the smell of her.

No two people have the exact same odor-identity or “smell fingerprint” which is determined by many factors including: our genes, skin type, diet, medicine, mood state and even the weather.



Up on the roof of the nasal cavity (the space behind your nose) is the olfactory epithelium.
The olfactory epithelium contains special receptors that are sensitive to odor molecules that travel through the air.
These receptors are very small - there are at least 10 million of them in the 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 10,000 different smells.

When the smell receptors are stimulated, signals travel along the olfactory nerve to the olfactory bulb.
The olfactory bulb is underneath the front of your brain just above the nasal cavity.
Signals are sent from the olfactory bulb to other parts of the brain to be interpreted as a smell you may recognize.

Identifying smells is the brain's way of telling about the environment.
Have you ever smelled something burning?
In an instant, your brain interpreted the smell and a problem and you know to check on your food that is burning.
You have learned to associate a certain smell with burning and now the brain remembers that smell so you recognize it.

Your sense of smell also can help you keep safe.
For example, it can warn you not to eat something that smells rotten or help you detect smoke before you see a fire.

http://library.thinkquest.org/05aug/00386/smell/smell.htm