Today you’ll learn about what really happens when we get a whiff of something, about the mechanism that allows dolphins to communicate with vocal fry, and the dark and windy history of body donation.
Today you’ll learn about what really happens when we get a whiff of something, about the mechanism that allows dolphins to communicate with vocal fry, and the dark and windy history of body donation.
Find episode transcripts here: https://curiosity-daily-4e53644e.simplecast.com/episodes/odor-receptors-whale-vocal-fry-body-donation
Odor Receptors
Whale Vocal Fry
Body Donation
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[SFX: INTRO MUSIC/WHOOSH]
NATE: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from Discovery. Time flies when you’re learnin’ super cool stuff. I’m Nate.
CALLI: And I’m Calli. If you’re dropping in for the first time, welcome to Curiosity, where we aim to blow your mind by helping you to grow your mind. If you’re a loyal listener, welcome back!
NATE: Today you’ll learn about what really happens when we get a whiff of something, about the mechanism that allows dolphins to communicate with vocal fry, and the dark and windy history of body donation.
CALLI: Without further ado, let’s satisfy some curiosity!
[SFX: WHOOSH]
CALLI: For decades, scientists have been trying to understand how you smell.
NATE: Yes. My aroma is complex. It’s like fresh linens on a spring day with notes of elk antler.
CALLI: Elk Antler? Okay. Let me rephrase that. Scientists at the University of California San Francisco have created the first ever 3D model of an odor molecule activating an odor receptor in humans.
NATE: Oh! They’ve figured out how we smell. As in like, how we do the smelling act. Like, how our sense of smell works.
CALLI: That’s it! You got it right on the nose. That’s for smelling like elk antler.
NATE: Ha!
CALLI: And this is actually a big deal with implications beyond just understanding how our olfactory senses function. That said, understanding olfaction is a huge deal in and of itself.
NATE: Olfaction is just another way of saying the sense of smell, right?
CALLI: Pretty much. And if you think about it, our sense of smell is not only really complex, it’s also incredibly important. It alerts us to danger, helps us figure out what to eat and what not to eat, gives us a sense of pleasure and also disgust.
NATE: Right. And, it turns out, he who smelt it, dealt it.
CALLI: I’m pretty sure he who said the rhyme did the crime.
NATE: Scientists can’t prove that.
CALLI: No, they can’t. But…there’s new science that shows our olfactory senses go far beyond just figuring out who dealt it. It can help us identify our family, help infants bond with their moms, and has even been tied to longevity. Which makes sense, because as our sense of smell declines, we could find food less appetizing, which could lead to poor nutrition. The point is, our sense of smell is incredibly complicated with a ton of knock-on effects that we just don’t fully understand. Which is why the team at UC San Francisco wanted to see for themselves what actually happens when an odor molecule meets an odor receptor.
NATE: It’s crazy to think about a sensor in your nose grabbing onto a molecule, analyzing it, and sending the data to your brain where it becomes perceived as a smell.
CALLI: It’s completely insane. And it happens with about 400 different receptors that can detect hundreds of thousands of scents that are made up from a cocktail of odor molecules. Each time one of those molecules is detected by receptors, the brain has a puzzle to put together. Scientists have been asking this one question for years: how do those odor molecules activate those receptors? And they’ve finally modeled it, using a receptor that responds to propionate - an odor molecule that helps give Swiss cheese that sorta rich, nutty aroma.
NATE: I would describe Swiss cheese as having a mild sour plastic aroma? But that’s just my smell receptors.
CALLI: Don’t get out your crackers just yet. Propionate, it turns out, sorta stinks by itself. But the receptor called OR51E2 loves it and actually seeks it out. Scientists think that OR51E2 might have evolved to help us figure out if our food has gone bad.
NATE: It’s not my dream job, but somebody’s gotta do it.
CALLI: So to model the meeting of the odor with the receptor, they used computer simulations and something called cryo-electron microscopy, a really difficult process that let researchers peek into the atomic structure of these molecules so they could study their shapes. Once they understood what they actually looked like and how they moved, they could model how the smell fit into the smeller.
NATE: A sort of olfactory meet-cute.
CALLI: For the stinky part of cheese.
NATE: So what will they do with this information?
CALLI: That’s actually the fun part. They want to map out the interactions between hundreds of these receptors and thousands of odor molecules. Eventually they could create artificial odors based on our new understanding of how a chemical’s shape affects the receptor. But the bigger picture has everything to do with our understanding of perception, itself. Knowing not just how we perceive the smells around us, but why. This is like seeing how we interact with the world around us at a molecular level, and getting closer to knowing why we perceive the world the way we do.
NATE: And maybe they’ll finally figure out who dealt it.
CALLI: I think we all know who dealt it, Nate.
NATE: Don’t blame me, I smell like linens and elk antler.
CALLI: Elk antler… yeah.
[SFX: WHOOSH]
NATE: Marine scientists have been studying the sounds of whales and dolphins for decades, but now, for the first time ever, a team has observed the structures that make those sounds and it’s (use vocal fry) waaaaaaaaayyyyyy coooooollll.
CALLI: Why are you talking like a Kardashian?
NATE: That’s my attempt at something called vocal fry, or “creaky voice,” and linguists have studied its use in people, especially in the speech of young women. Well…it turns out that dolphins, pilot whales, and sperm whales toooooootally use it, too.
CALLI: I guess that’s siiiick…
NATE: Okay, we are bad at this enough of that, because this study is actually really fascinating because scientists have been studying the haunting vocalizations of whales and dolphins for ages.
CALLI: We’ve probably all heard recordings. The eerie moans, the clicks, the whistles.
NATE: All of that. We’ve known for decades that these sounds are used for social communication and echolocation. And they actually make sounds in different registers - just like we do. There’s the falsetto…
CALLI: …the squeaks.
NATE: Yep. The squeaks and the whistles are in that falsetto range. There’s also the chest register, which would be like our normal speaking voice. And then…there’s the vocal fry register.
CALLI: Is that for when they’re totally just hanging out, drinking some boba, sending snaps? Do people still send snaps?
NATE: No idea. Now THAT would be quite a discovery. No. They use vocal fry when they’re echolocating.
CALLI: That makes waaaaaay more sense.
NATE: But here’s the thing: we’ve heard them as long as we’ve observed the animals, but despite advances in science and tech, scientists didn’t know how they made these sounds.
CALLI: Why was it so hard to figure out? Couldn’t dissections give them answers?
NATE: Dissections could only get them so far. Yes - scientists mapped out the anatomy of these animals, but in order to understand how sound is created, they really needed to see it in action. Imagine seeing a human voice box. Based on clues, you can kinda get a sense of what it does, but you really have to see it to believe it.
CALLI: So…how do you see inside a whale while it's making sounds?
NATE: That’s a good question, and one that scientists have finally found an answer to. In the past, researchers have tried to use x-rays and sound triangulation to figure it out. But nothing worked. Until now. Scientists have long thought that the sounds are produced in the nasal cavity, so Dr. Coen P.H. Elemans, a biologist at the University of Southern Denmark, and his team filmed the creation of the sounds by inserting endoscopes into the nasal cavities of some Atlantic bottlenose dolphins and harbor porpoises.
CALLI: That’s a movie with quite a soundtrack.
NATE: I’ll say. They found that the animals used what they call ‘phonic lips’ and confirmed that these sounds were produced in the nasal cavities. But this led to another interesting discovery: scientists believed that these sounds were created when air moves past these internal structures and creates vibrations.
CALLI: Isn’t that how our vocal cords work?
NATE: Pretty much. But this study found that the whales and dolphins actually need very little air to create those loud echolocation clicks. That solves a problem that has befuddled scientists for a long time: how do they make sounds 1,000 feet down and still have enough air to survive?
CALLI: I never thought of that, but it would be pretty hard for us to make small talk underwater, too.
NATE: Totally. With this new discovery, Dr. Elemans thinks we have a route to recreating these sounds more accurately, and to gaining a better understanding of how these animals communicate.
CALLI: That’s pretty sweeeeeeet.
NATE: I know riiiiiighhhht?
CALLI: You’re much better at this than I am.
NATE: Lower voice might help? Maybe.
[SFX: WHOOSH]
CALLI: John Scott Harrison was a congressman from Ohio in the mid-1800s who was famous for a couple of reasons. The first: he is the only person who is both the son and the father of U.S. Presidents. The second reason is for… grave robbing.
NATE: Wait. What?
CALLI: Yep. His dad, William Henry Harrison was our 9th President, and his son, Benjamin, was the 23rd and his body was stolen from its grave and sold to a medical school so it could be dissected by eager young med students.
NATE: Oh no.
CALLI: Oh yes. This incident actually led to some major changes in the way cadavers find their way onto dissection tables.
NATE: You mean people back then didn’t just donate their bodies to science?
CALLI: No. In fact, donating one’s remains to medical schools is a relatively recent phenomenon. Susan Lawrence, a Professor of History at the University of Tennessee, and her colleague, Susan E. Lederer, who is a Professor of Medical History and Bioethics at the University of Wisconsin-Madison are writing a book on the history of body donation.
NATE: So…if donating remains is a relatively recent thing, were all cadavers stolen in the past?
CALLI: Not exactly. But it is a pretty dark, winding history. And the thing is, modern medicine requires dissection. Even our understanding of body functions and disease from hundreds of years ago relied on medical students actually being able to see what’s inside of the body. I mean, imagine getting your spleen removed by a surgeon who’d only read about spleens on the internet.
NATE: Yikes.
CALLI: But for centuries, the idea of cutting up human beings was seen as sacrilegious and, well, obviously, revolting. So medical schools were often in short supply of cadavers.
NATE: Aha. Enter grave robbers.
CALLI: Right. As science and medicine advanced, the need for cadavers was so great and the supply so low, that dead bodies became a bit of a commodity. And when railroads began crisscrossing the nation, grave robbers could dig up a recently buried body and quickly ship it off to a medical school across state lines where its grieving family would never find it.
NATE: So how did that change?
CALLI: John Scott Harrison’s body snatching helped put this in the national spotlight. So called Anatomy Laws went on the books in more and more states. They said that bodies of unclaimed poor could be made available for dissection. Also up for grabs - executed criminals. In fact, sometimes judges would actually add dissection to a condemned criminal’s sentence, just to make the sentence a little worse.
NATE: As if execution isn’t enough.
CALLI: The bodies of enslaved people were also often exploited. And after slavery was abolished, the bodies on the dissection table still tended to be the poor, the unclaimed, the indigent. Until the late 1800s, when a trend took hold that would lead to today. People became more willing to donate their bodies to science.
NATE: What caused this change?
CALLI: It’s not clear exactly what changed, but more and more people really wanted to help advance the science of the day. Some wanted doctors to study their diseases after they passed. And still others just wanted to avoid funeral costs. Eventually, in the 1950s and 1960s, the movement gained so much steam that even Dear Abby was telling readers to donate their bodies.
NATE: So there’s no more grave robbing?
CALLI: There’s no need. By some estimates, nearly 20,000 people donate their bodies to medical schools each year in the U.S. alone. Fortunately, the stigma has changed in the past 200 years, and it is now viewed as an honorable, if not heroic thing to do.
NATE: One last question.
CALLI: Shoot.
NATE: Was John Scott Harrison really the son of a president AND the father of one?
CALLI: I know! It’s crazy, right?
[SFX: WHOOSH]
NATE: Let’s recap what we learned today to wrap up.
CALLI: Scientists have modeled the coupling of an odor molecule with a receptor for the first time ever. This research will allow scientists to create new and novel odors and help us better understand the mechanisms behind our perception.
NATE: Marine researchers used an endoscopic camera to film dolphins making sounds from inside their nasal cavities to finally understand the mechanisms behind the sounds. Dolphins and toothed whales vocalize in three registers, like humans, and it was discovered that very little air is needed for echolocation, which is why they are able to stay underwater and still communicate.
CALLI: While some 20,000 Americans donate their bodies to medical schools every year today, that is a recent trend. In the mid 19th century and before, dissection was seen as gruesome and sacrilegious, which led to a scourge of grave robbers and the exploitation of the poor, the indigent, and minorities. Thankfully, the stigma has been removed and the donation of one’s remains to science is viewed more positively now.
___________________________________________
NATE: Have you ever heard of The Amber Room? It was a room in Russia, decorated in amber and gold, and during WWII, the Nazi’s stole the entire room. To this day, the whereabouts of The Amber Room remain unknown.
CALLI: On Expedition Unknown, you’ll travel the globe with Josh Gates as he investigates some of humanity’s greatest feats and most iconic legends… like the missing items of the Amber Room.
Listen to Expedition Unknown wherever you get your podcasts.