When I graduated from medical school many years ago, I remember being told that in about ten years, half of what I had been taught would be outdated, and the other half would be dead wrong. Being a young, newly minted, and smug physician, I doubted those who said as much.
Now, over four decades later, I have to admit, they had a point. Back in the 1950s the doubling time of medical knowledge was about fifty years, and in my day, about seven years, but now it’s said to be down to just over two months.
Certainly, most of this must be due to the increased funding for medical research in an apparent attempt to improve our lives. But it’s amazing to consider what scientists think of to investigate.
Case in point, a recent article in Popular Science offering to explain “Why we have two nostrils instead of one big hole.”
For Your Consideration, the Nasal Cycle
Now, I remember being taught about the Krebs cycle in biochemistry, and the cardiac cycle during my clinical training, but the “nasal cycle”? As the article notes, “It turns out that each nostril behaves differently to the other nostril throughout the day.”
Besides the nose helping the mouth to bring in air, it also screens out dust and pollutants, while warming and adding water to prepare it for the lungs which improves gas exchange. The parts of the nose that do this job are called the turbinates, three on each side, the lowest of which is visible. Increased blood flow into the mucous membrane overlying the turbinates, which causes them to swell a bit, is how they warm, filter, and humidify the incoming air.
But there seems to be a time limit to turbinate efficiency because, as the article states, “Every few hours one side of the nose is more open and handles most of the airflow while the other processes less air, enabling it to recover moisture.” This is all regulated by the nervous system.
But There’s More!
What other important function does the nose perform?
As the article continues,
Smell is closely linked to breathing. As we breathe, odor molecules enter the nostrils, dissolve in the mucus lining and bind to neurons that send signals to the brain. Thanks to the nasal cycle, air flows into the nostrils at different speeds and so each nostril handles odors differently.
What does this mean in practical terms? The article points out, and as an ID friend recently put it, “we have ‘stereo’ smelling for helping locate directions of scent, and asymmetrical intake, which gives us gradients of scent between slow and quick dissolving chemicals.”
To perform these important functions, which type of space, “one big hole” or “two (restrictive) nostrils,” do you think would do a better job, the nature of which could be vital for survival?
The Direction of Smells
It’s remarkable to consider how the humble nose was so well designed and engineered for respiratory function, and for tracking the direction of smells through “3D olfaction.” It’s also remarkable that someone even to do the research to find these things out! Kudos to those scientists in the trenches for providing us with more and more information on how the body, and not only the human body, works.
Now you can impress your family and friends with your knowledge of one more of the many different “cycles” in the body — the nasal cycle.