Has a vague scent in the air ever caught your attention? You know you’ve smelled it somewhere before but you just don’t know where? Well, our sense of smell is incredible and many scents are strongly linked with memories. The average adult can distinguish 10,000 different scents from baking bread, to a favorite perfume, to apple blossoms, to road kill skunk. How does our nose do it?
When you breathe in through your nose, air rushes into your nasal cavities. The majority of the space in your nose is dedicated to filtering this air before it heads to your lungs. But a small portion of your nose is the olfactory epithelium which is filled with 40 million different receptor neurons, all of which are specific to certain odor molecules.
An amazing 3% of all the genes in your DNA codes for these receptor neurons. And unlike most neurons, these ones are replaced every month or so.
Now, air isn’t just filled with air. It’s full of odorants, molecules that we can smell. These odorants become trapped in a mucus layer covering the olfactory epithelium. They dissolve and trigger different neurons which zip electrical signals right up to the olfactory bulb which is actually part of your brain.
Interestingly enough, the nose is the only one of all five senses directly connected to the brain. Different parts of your brain, including your memory and emotion centers, work to determine what the smell is and how you should feel about it.
Different neurons in the olfactory epithelium respond to pain. When you smell something that can burn or hurt you, like a chemical, these cells trigger a pain response so you get a sharp warning sting.
You might have noticed that smell is linked closely to taste. That’s why plugging your nose when you chugged down that cold remedy made it easier to swallow or why when you’re sick you can’t taste a thing. As you chew, air is pushed up into your nose and those odorants smack right into that mucus layer. These odorants actually tell your brain more about what you’re eating than your taste buds can.
Our sense of smell is a marvelous testimony to the incredible design of the Creator. So next time you breathe in the smell of your favorite dessert cooking in the oven, stop and thank God for His caring and wonderful design.
I’m David Rives…Truly the heavens declare the glory of God.