What Does That Dangly Thing in the Back of Your Throat Do?

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iStock

Uvula image via Shutterstock

The uvula is one of the weirdest looking features of the human body. Yet despite its infamy, scientists have spent centuries puzzling over its function.

The hangy ball's full name is the “palatine uvula,” referring to its location on your soft palate. Not to be confused with the uvula vermis, a lobe of the cerebellum, or the uvula vesicae, in the urinary bladder. 

Through history, scientists have had many theories about the uvula. Among them:

That it once helped guide the flow of food and water, and, in humans, was a mere remnant from previous mammals who had to lean down to eat and drink.
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That it induces the gag reflex. And therefore isn’t the best place to get a piercing.
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That it contributed to “chronic cough.” A problem that 19th-century doctors treated with a “simple” “clipping” procedure.
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That it contributes to cardiovascular problems like sudden infant death syndrome (SIDS) and sleep apnea.

Even today, some doctors treat sleep apnea by having the uvula removed. Unpleasant as that sounds, much of the recent uvular research has come about by studying uvulopalatopharyngoplasty patients (uvula-less people). Several such studies have concluded that the uvula is really good at excreting saliva. A lot of saliva, in a really short amount of time. Another study compared the soft palates of eight different mammals, and found that a small, underdeveloped uvula was found in only two baboons.

Don’t Leave Us Hanging

So what does the dangly throat thing do? Because the uvula is basically unique to humans, scientists basically agree that it primarily serves as an accessory to speech. You know what it’s like to have your throat go dry before talking to a large group? The uvula is there to provide the proper lubrication for complicated human speech. In time, we’ll likely learn that the uvula does some other cool things to boot, but to quote one study on the subject, it “may be another marker of human evolution that differentiates man from other mammals.” For now, that’s pretty cool.

This post originally appeared in 2012.

Shocker: This Electric Eel Delivers More Voltage Than Any Creature on Earth

stacey_newman/iStock via Getty Images
stacey_newman/iStock via Getty Images

Eels are proving to be more slippery than previously believed. A newly identified species of these skinny fish (yes, eels are really fish) delivers more electric voltage than any other creature on the planet.

All species in their taxonomic order (Gymnotiformes) are capable of producing a modest electrical field to help them navigate, a perk that compensates for their poor vision. But electric eels (in the genus Electrophorus) pack a far more potent punch. They bear three organs full of cells that can produce electricity on demand. The cells act as a defense mechanism and can effectively taser prey into submission.

In a study published in Nature Communications, researchers collected more than 100 electric eels in the Amazon region and analyzed their DNA, voltage, and habitat. To their surprise, they found that the single known species of electric eel, Electrophorus electricus, was actually three distinct species. They gave the two new ones the very heavy metal names of E. varii and E. voltai. The latter (named for Alessandro Volta, who invented the electric battery) produced the strongest shock: 860 volts, topping the previous record of 650 volts.

Why the varying strength? The researchers suggested that some eels occupy water with low salt content, and therefore reduced conductivity. A stronger charge may be needed to deliver an effective jolt.

While those numbers sound formidable, their low current means a shock wouldn’t necessarily be harmful to a human. Voltage is the measure of pressure of the flow of electrons; current, or amperage, is the volume of electrons. Eels have high voltage but low current; household power outlets have lower voltage but more current and can be deadly. Eels might startle you with a shock, but it won't be fatal.

If you should find yourself in a school of electric eels bent on subduing you, however, the shocks could result in brief incapacitation that could lead to drowning or an aggravation of an existing heart condition. The study authors hope to eventually film a coordinated eel attack on (non-human) prey.

The discovery of two new species was “quite literally shocking,” lead author Carlos David de Santana told The New York Times.

[h/t Phys.org]

Does the Full Moon Really Make People Act Crazy?

iStock.com/voraorn
iStock.com/voraorn

Along with Mercury in retrograde, the full moon is a pretty popular scapegoat for bad luck and bizarre behavior. Encounter someone acting strangely? Blame it on the lunar phases! It's said that crime rates increase and emergency rooms are much busier during the full moon (though a 2004 study debunked this claim). Plus, there's that whole werewolf thing. Why would this be? The reasoning is that the moon, which affects the ocean's tides, probably exerts a similar effect on us, because the human body is made mostly of water.

This belief that the moon influences behavior is so widely held—reportedly, even 80 percent of nurses and 64 percent of doctors think it's true, according to a 1987 paper published in the Journal of Emergency Medicine [PDF]—that in 2012 a team of researchers at Université Laval's School of Psychology in Canada decided to find out if mental illness and the phases of the moon are linked [PDF].

To test the theory, the researchers evaluated 771 patients who visited emergency rooms at two hospitals in Montreal between March 2005 and April 2008. The patients chosen complained of chest pains, which doctors could not determine a medical cause for the pains. Many of the patients suffered from panic attacks, anxiety and mood disorders, or suicidal thoughts.

When the researchers compared the time of the visits to the phases of the moon, they found that there was no link between the incidence of psychological problems and the four lunar phases, with one exception: in the last lunar quarter, anxiety disorders were 32 percent less frequent. "This may be coincidental or due to factors we did not take into account," Dr. Geneviève Belleville, who directed the team of researchers, said. "But one thing is certain: we observed no full-moon or new-moon effect on psychological problems."

So rest easy (or maybe not): If people seem to act crazy during the full moon, their behavior is likely pretty similar during the rest of the lunar cycle as well.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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