The human body is an amazing thing. For each one of us, it’s the most intimate object we know. And yet most of us don’t know enough about it: its features, functions, quirks, and mysteries. That’s why we’re launching a new series called The Body, which will explore human anatomy, part by part. Think of it as a mini digital encyclopedia with a dose of wow.
 

Your nose is more than just a bump on your face—it’s an important part of the respiratory system and affects many other senses, including your taste and hearing. For being something that’s so central to our daily interactions with the world, there’s still a surprising amount to discover about the nose. Here's a bit of what we do know. 

1. SCENT DETECTIVE: WHAT THE NOSE KNOWS

Although the human nose is weak compared to canine sniffers, our noses can detect 1 trillion smells. Strangely, scientists still aren’t sure exactly how we smell. For decades, researchers thought the olfactory system worked through receptor binding, meaning molecules of different shapes and sizes bonded to specific parts of the nose like puzzle pieces, triggering smell recognition in the brain. But recently, Luca Turin, a biophysicist at the Institute of Theoretical Physics Ulm University, has proposed the nose detects smell through quantum vibrations. Turin suggests the frequency at which different molecules vibrate helps the nose identify them as different scents. The theory could explain why molecules of the same shape smell quite differently. Intriguing as it is, this new theory hasn’t been tested enough to be universally accepted.

2. EVOLUTION: JUST HOW DID WE GROW HONKERS, ANYWAY?

As anyone who’s been to a zoo probably knows, great apes (the closest human ancestors) have flat nasal openings—and researchers found that type of nose is far more effective at inhaling air than the human version. So what’s up with ours? Scientists think the shape might be a by-product of our big brain. The growing cerebellum forced human faces to become smaller, which probably affected the nose as well.

3. SUPER SNIFFERS: WHEN A ROSE DOESN'T SMELL AS SWEET

In the battle of the sexes, women’s noses come out on top. When tested for odor detection and identification, women score consistently higher than men. This might have something to do with the size of their olfactory bulb, a structure in the brain that helps humans identify smells. One study found that women have, on average, 43 percent more cells in their olfactory bulb than men do—meaning they can smell more smells.

4. EATING WITH YOUR NOSE: THE ROLE OF SCENT IN FOOD

Think you like chocolate just because it tastes good? Think again. Smell is responsible for 75 to 95 percent of flavor, which explains why plugging your nose helps you swallow something unappetizing. More recently, chefs and neurologists have teamed up to create meals for cancer patients and others with a diminished sense of smell, such as the elderly. Cooking meals tailored to the smell-less could help stave off depression and improve the appetite without over-relying on sugar and salt.

5. REBUILDING A FACE: WHEN ONE NOSE IS NOT ENOUGH

A new nose grows on a patient's forehead in a hospital in Fuzhou, China, in 2013. Surgeons grew the new nose to replace the patient's original nose, which was badly injured in an accident. Image credit: STR/AFP/Getty Images

 
When people have cancer or are in an accident, the nose can become infected or even be completely destroyed. But fear not. Plastic surgeons have a nifty way to regrow your nose—on your forehead. Using cartilage from the ribs and tissue expanders that allow the skin to stretch and grow, a new nose can be formed to replace the old one. And while a nose growing out of your forehead looks odd, it's actually one of the best places for a new nose to grow. The forehead's blood vessels can be harnessed to help grow the tissue, and removing the new nose only leaves a small scar. Doctors have performed the procedure in the U.S., China, and India.

6. SOMATOSENSORY: NOT ALL SMELLS ARE SMELLS

The nose doesn’t just translate odors in the nasal passage—the tip is also full of nerves that detect pain and temperature. This helps us “smell” non-odor smells. Even people who can no longer smell things with their olfactory system can detect substances like menthol, the minty compound that makes your skin tingle. (Unfortunately, they can’t detect pure scents like vanilla.)

7. THE BODY'S AIR FILTER: MORE THAN JUST A SNIFF MACHINE

The average adult breathes around 20,000 liters of air every day, which keeps the nose quite busy. As the first line of defense for the lungs, the nose filters out small particles like pollen and dust. It also adds moisture to the air and warms it so the lungs are saved from any irritation.

8. SMELL DISORDERS: AN ODORLESS WORLD

There are plenty of things that can go wrong in your nose. Allergic rhinitis, sinus infections, and broken noses are just a few. But perhaps less well known are disorders that affect the nose’s ability to smell. Anosmia is the complete inability to detect odors and can be caused by illness, aging, radiation, chemical exposure, or even genetics. Equally bizarre are parosmia and phantosmia: The former changes your perception of smells, and the latter creates the perception of smells that don’t exist. Luckily, only 1 or 2 percent of North Americans suffer from any smell disorders.