What Causes the Smell of Things?

[i.mehrzad]

Smelly stuff?

Well what is the cause that something smells. That is what does a substance emit before entering the nasal chamber of our nose that enables us to smell things?? Or does it really emit anything?

 

[Moonbear]

Yes, for us to smell something, small particles must become airborne. There are then receptors in the nose that these particles interact with (different types of receptors can interact with different types of airborne chemicals). The information from the numbers and types of receptors that are "triggered" when these chemicals bind to them is then sent to the brain where it is processed and interpreted.

You may or may not know that just a few years ago, two scientists, Axel and Buck, won the Nobel Prize in Physiology and Medicine for their work on the olfactory system. There is a very nice explanation of how the system works, written as a press release for a general audience, on the Nobel website.

http://nobelprize.org/nobel_prizes/medicine/laureates/2004/press.html

I'm certainly not going to attempt to explain it any better than Nobel prize winners who have studied that system.

 

[ravenprp]

The smell of things is caused by molecules that are released from the substance and interact with the olfactory receptors in our nose. These molecules are called volatile organic compounds (VOCs) and they are responsible for the unique scent of different substances. The specific combination and concentration of VOCs determine the smell of a particular item.

For example, a ripe banana releases a high concentration of ethylene gas, which is responsible for its distinct smell. On the other hand, the smell of freshly cut grass is caused by a combination of compounds called green leaf volatiles.

Interestingly, our sense of smell is closely linked to our emotions and memories. This is because the olfactory receptors are connected to the limbic system, which is responsible for processing emotions and memories. That's why certain smells can trigger strong emotions or bring back vivid memories.

In conclusion, the smell of things is caused by the release of molecules that interact with our olfactory receptors, and this can evoke different emotions and memories. So next time you smell something, remember that it's the result of a complex chemical process that our sense of smell allows us to experience.