No, Scientists Have Not Found a "New Organ"

Illustration by James Peter Warbasse via Wikimedia Commons // Public Domain

 
The human body is an amazing and expansive place, full of strange twists and turns. It’s likely we’ll never discover all its secrets, but we do have a pretty solid grasp on the major parts. So even though new research has convincingly made the case for reclassifying the mesentery—a folded membrane that connects your intestines to the wall of your abdominal cavity and keeps everything snugly in place—as a single, continuous organ, scientists have not, as some headlines proclaim, discovered a “brand-new organ.” In fact, we've known about the existence of the mesentery (pronounced MEH-zun-terry) for centuries; Leonardo da Vinci even included it in his anatomical notes.

The mesentery has historically been seen as a series of unimportant attachments to the abdominal lining. But researcher J. Calvin Coffey of the University Hospital Limerick in Ireland suspected that there might be more to it. He and his colleagues examined the membrane and surrounding tissue under a microscope in 2012. They found that, rather than a group of disconnected but similar pieces, the mesentery was actually all one piece. The researchers published their findings in The Lancet Gastroenterology & Hepatology.

 
Inspired by this realization, Coffey initiated a campaign to reclassify the mesentery as a separate organ. He believes that full organ status is the key to understanding what’s going on in our guts.

“Up to now there was no such field as mesenteric science,” he said in a statement. “Now we have established anatomy and the structure. The next step is the function. If you understand the function you can identify abnormal function, and then you have disease.”

His lobbying paid off; the latest edition of Gray's Anatomy categorizes the mesentery as an organ.

Coffey’s new paper, written with his colleague D. Peter O’Leary, makes a strong case for initiating the mesentery into the organ club. “The mesentery should be subjected to the same investigatory focus that is applied to other organs and systems,” they write.

“This is relevant universally,” Coffey added in the statement. “It affects all of us.”

nextArticle.image_alt|e
iStock
How Does Catnip Work?
iStock
iStock

If you have a cat, you probably keep a supply of catnip at home. Many cats are irresistibly drawn to the herb, and respond excitedly to its scent, rubbing against it, rolling around on the floor, and otherwise going nuts. There are few things that can get felines quite as riled up as a whiff of catnip—not even the most delicious treats. But why does catnip, as opposed to any other plant, have such a profound effect on our feline friends?

Catnip, or Nepeta cataria, is a member of the mint family. It contains a compound called nepetalactone, which is what causes the characteristic catnip reaction. Contrary to what you might expect, the reaction isn’t pheromone related—even though pheromones are the smelly chemicals we usually associate with a change in behavior. While pheromones bind to a set of specialized receptors in what’s known as a vomeronasal organ, located in the roof of a cat's mouth (which is why they sometimes open their mouths to detect pheromones), nepetalactone binds to olfactory receptors at the olfactory epithelium, or the tissue that lines the mucus membranes inside a cat’s nose and is linked to smell.

Scientists know the basics of the chemical structure of nepetalactone, but how it causes excitement in cats is less clear. “We don’t know the full mechanisms of how the binding of these compounds to the receptors in the nose ultimately changes their behavior,” as Bruce Kornreich, associate director of the Cornell Feline Health Center, tells Mental Floss. Sadly, sticking a bunch of cats in an MRI machine with catnip and analyzing their brain activity isn’t really feasible, either from a practical or a financial standpoint, so it’s hard to determine which parts of a cat’s brain are reacting to the chemical as they frolic and play.

Though it may look like they’re getting high, catnip doesn’t appear to be harmful or addictive to cats. The euphoric period only lasts for a short time before cats become temporarily immune to its charms, meaning that it’s hard for them to overdo it.

“Cats do seem to limit themselves," Michael Topper, president of the American Veterinary Medical Association, tells Mental Floss. "Their stimulation lasts for about 10 minutes, then it sort of goes away.” While you may not want to turn your house into a greenhouse for catnip and let your feline friend run loose, it’s a useful way to keep indoor cats—whose environment isn’t always the most thrilling—stimulated and happy. (If you need proof of just how much cats love this herb, we suggest checking out Cats on Catnip, a new book of photography from professional cat photographer Andrew Martilla featuring dozens of images of cats playing around with catnip.)

That said, not all cats respond to catnip. According to Topper, an estimated 70 percent of cats react to catnip, and it appears to have a genetic basis. Topper compares it to the genetic variation that causes some individuals to smell asparagus pee while others don’t. Even if a cat will eventually love the smell of catnip, it doesn’t come out of the womb yearning for a sniff. Young kittens don’t show any behavioral response to it, and may not develop one until several months after birth [PDF].

But some researchers contend that more cats may respond to catnip than we actually realize. In one 2017 study, a group of researchers in Mexico examined how cats might subtly respond to catnip in ways that aren’t always as obvious as rolling around on the floor with their tongue hanging out. It found that 80 percent of cats responded to catnip in a passive way, showing decreased motor activity and sitting in the “sphinx” position, an indicator of a relaxed state.

There are also other plants that have similar effects on cats, some of which may appeal to a wider variety of felines than regular old catnip. In a 2017 study in the journal BMC Veterinary Research, researchers tested feline responses to not just catnip, but several other plants containing compounds similar in structure to nepetalactone, like valerian root, Tatarian honeysuckle, and silver vine. They found that 94 percent of cats responded to at least one of the plants, if not more than one. The majority of the cats that didn’t respond to catnip itself did respond to silver vine, suggesting that plant might be a potential alternative for cats that seem immune to catnip’s charms.

Despite the name, domestic cats aren’t the only species that love catnip. Many other feline species enjoy it, too, including lions and jaguars, though tigers are largely indifferent to it. The scent of the plant also attracts butterflies. (However, no matter what you’ve heard, humans can’t get high off it. When made into a tea, though, it reportedly has mild sedative effects.)

The reason Nepeta cataria releases nepetalactone doesn’t necessarily have to do with giving your cat a buzz. The fact that it gives cats that little charge of euphoria may be purely coincidental. The chemical is an insect repellant that the plant emits as a defense mechanism against pests like aphids. According to the American Chemical Society, nepetalactone attracts wasps and other insect predators that eat aphids, calling in protective reinforcements when the plant is in aphid-related distress. That it brings all the cats to the yard is just a side effect.

Because of this, catnip may have even more uses in the future beyond sending cats into a delighted frenzy. Rutgers University has spent more than a decade breeding a more potent version of catnip, called CR9, which produces more nepetalactone. It’s not just a matter of selling better cat toys; since catnip releases the compound to ward off insects, it’s also a great mosquito repellant, one that scientists hope can one day be adapted for human use. In that case, you might be as excited about catnip as your cat is.

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

nextArticle.image_alt|e
iStock
A Baby's Cries Might Hint at What the Child Will Sound Like as an Adult
iStock
iStock

Babies may be incapable of talking, but at just a few months old, they've already developed many of the characteristics that will one day make their speaking voice distinct. That's the takeaway from a new study, reported by The New York Times, in which a team of bioacoustic researchers found that you can tell what infants will sound like at age 5 by analyzing their cries.

For their study, published in the journal Biology Letters [PDF], the researchers recorded the voices of 15 French children 4 to 5 years old. They then compared the clips to the children's "mild discomfort cries" recorded when they were 2 to 5 months old. The results showed that a baby's voice can be used to predict 41 percent of the variances they will have in their vocal pitch at age 5.

Other studies have suggested that what our voices sound like when we're young is a strong indicator of what they will sound like later on—even after puberty changes our vocal cords. A boy's voice pitch at age 7 can predict up to 64 percent of the distinguishing features his voice will have as an adult.

The study authors write that many of these variances may develop before childhood, and potentially in utero: "These observations suggest that inter-individual differences in [voice pitch] arise early in life and are largely unaffected by puberty, and raise the possibility that [pitch] may even be determined before birth."

The most important markers that determine pitch are the length, size, and tension of our vocal folds. But those aren't the only determinants: Environmental factors like smoking, pollution, and climate can affect how our voices sound as well, though these changes are usually temporary.

[h/t The New York Times]

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios