Smelling Snots

Take a whiff of that morning coffee. Those lovely, fragrant molecules dance their way from the coffeepot to your nostrils, where nostril hairs filter out any unwelcome particles.

Here, they enter your olfactory epithelium, like a lab for odor analysis that’s built into your body. Here’s how I described this process in The Nose Knows:

About six million tiny receptor cells (in humans) act as docking stations, waiting for the right molecules. Each of these receptors is like a bouncer at a club: only a certain type can get in.

As soon as this connection is made, an electrical signal goes to the brain. The connecting molecules complete a circuit of sorts, and ions flow from the olfactory cell to the temporal lobe, the part of your brain that sits behind and under your ears.

If the signal matches a stored memory, you will recognize the odor.

When I brew my morning coffee, I often think about this connection being formed. This is a truly wonderful process: nature has created a powerful program (hardware and software inclusive) that processes individual molecules, designed to keep us safe and help us find delicious things to drink.

That’s all true, but there’s another really noteworthy part of the process I want to call attention to today. It might seem kind of gross, but it’s snot that big of a deal.

Of course, I’m talking about mucous—you know, that stuff you’re always trying to get rid of? Well, it turns out that snot is your friend when you’re trying to smell.

When those fragrant, nutty, chocolaty molecules from your morning coffee enter your nostrils, they find a warm, moist place—all the better to catch and trap incoming particles, protecting the lungs from inhaling something dangerous.

Before the odor molecule can be detected by the olfactory epithelium, the clubs where these bouncers work the doors, they need to be dissolved. That’s why the entire apparatus is covered in mucous, which has the perfect blend of salts and proteins to safely deliver odor molecules into the epithelium.

There’s even a particular adaptation embedded in your snot. Particles called OBPs (Odorant Binding Proteins) latch onto the specific odor molecules, helping to ensure enough particles reach the bouncers and the eventual detection zone.

If the bouncers working at the olfactory epithelium are at the door to the club, these little OBPs are a bit like someone running up to the line outside to grab random people and bring them to the door. Only VIPs can get into this club.

Come with me if you want to get in, the OBPs stay. Otherwise, you might be waiting forever.

If you get used to a smell, it could be because mucous keeps you experiencing an odor if you don’t flush it out every now and then. This can be psychological too, because our brains can rewrite the smell at the analysis lab itself. We decide that it’s not a new smell, so we kind of learn to ignore it. Other times, though, blowing your nose really will help you to clear out a smell.

Think about the odors embedded in there, going into the trash can or down the toilet after being safely deposited into a tissue.

I don’t know if knowing this will help you much in your daily life, but maybe it will at least make it easier to bear a runny nose the next time you have one.

Wanna find out next about what happens when you sneeze? Come along with me next to here: