Do you have a favorite smell? Perhaps you simply adore the smell of rosemary or old books. You can detect all kinds of odors thanks to your sense of smell. Although you might not even think about it most of the time, the ability to smell things is rather fascinating and there's actually a lot more to it than you might think.
Have you ever stopped to think about how your sense of smell works, and why you love certain smells? If not, why not learn how your sense of smell works today?
Let's take a look at how your body's sense of smell works and the mechanisms your body uses to identify various different odors.
Experiencing sensations
Do you have a favorite ice-cream flavor? Which one is it? Does it smell sweet? What about that feeling when you burn your hand with the iron? Is it painful or what? Can you describe the different sensations that you get in these two situations?

Thanks to our five senses we are able to experience these sensations and many more. Our senses are designed for us to enjoy from everything that surrounds us but also to keep us alert and safe. We use them all the time without being fully aware of how important they are.
Sniff, sniff
Here we will talk about olfaction, or the sense of smell.
The sense of smell is quite complex. If you remember, our tongue, or more specifically our tastebuds, can detect up to four different tastes. It is not like that with the nose. Just recently, scientists from the Rockefeller’s Laboratory of Neurogenetics and Behavior calculated that humans can detect around three trillion odor mixes. Can you imagine that?
Of course, this amazing yet complex job couldn’t be performed only by our nose and its structures. When we smell, both our nose and brain work as a team to detect, process and send back messages, so that we know the difference between the smell of smoke coming from a fire from the smell of smoke from a cigar.
The process of smelling
When we inhale air into our lungs we are taking oxygen in, to keep us alive, but we also take small odor particles that come from everything that surrounds us.
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When an odor molecule reaches the olfactory epithelium, it gets in contact with the cilia and switches on a signal that travels from the cilia to the other side of the hair cells, through the nerve fibers, until it reaches the olfactory bulb. The olfactory bulb has connections that send the odor signal to specific parts of the brain, mainly to the olfactory cortex, the hippocampus, the amygdala and the hypothalamus.
Is in these regions were the information is processed and codified to finally let us know what exactly we are smelling at that particular moment.
Other Things You Didn't Know About Your Sense Of Smell
Smell disorders
Can you imagine a world without odors? People suffering from anosmia are not able to sense smell.This condition is usually caused by a head trauma that damages the olfactory neurons or a severe sinus illness, but can also be caused by nose abnormalities, inflammation of the nasal passages due to high fever, some antibiotics, alcoholism and drug addiction, some neurodegenerative diseases and other mental problems.

In anosmia, not only the sense of smell is altered but also the sense of taste.
Whenever the sense of smell is disrupted, for example when going through a cold, the only perception the brain gets from food is the one detected by our taste buds, which is very simple, compared to what our nose can detect. This is the reason why food seems to be flavorless.
It smells like home
Have you noticed that when you detect a certain smell you tend to remember situations, people or things related to that particular odor? For example, does the smell of freshly baked cookies remind you of your grandma’s house? Or does the smell of specific man cologne make you think of your boyfriend and the day you two met?
The limbic system is in charge of emotional behavior and memory processes, so it is the one that makes us develop feelings towards situations we live, people we meet and objects we own. It is not strange then that certain smells make us recall childhood memories or wake up feelings inside us that we had not felt in a long time.
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Senses make us aware of the world we live in, but I believe that the most impressive one is the sense of smell. It plays a major role during our growth and development as kids; the smell of pheromones attracts us to our significant other and not somebody else; and it can even save us from threats like fires or gas leaks.
We could say that an odorless world would certainly lack of excitement. Think about this and next time, don’t take your sense of smell for granted.
- BUSHDID, C., MAGNASCO, M. O., VOSSHALL, L. B. & KELLER, A. 2014. Humans can discriminate more than 1 trillion olfactory stimuli. Science, 343, 1370-2.
- Photo courtesy of Effeietsanders by Wikimedia Commons : commons.wikimedia.org/wiki/File:Woman_smelling_rose.jpg
- Photo courtesy of Orin Zebest by Flickr : www.flickr.com/photos/orinrobertjohn/3081377348
- www.brainfacts.org/sensing-thinking-behaving/senses-and-perception/articles/2012/taste-and-smell/
- homepage.psy.utexas.edu/HomePage/Faculty/Pillow/courses/perception09/slides/Lec23_Olfaction.pdf
- faculty.washington.edu/chudler/nosek.html
- faculty.washington.edu/chudler/chems.html
- www.nhs.uk/conditions/anosmia/Pages/Introduction.aspx