Odor Receptors, Whale Vocal Fry, Body Donation

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Hi, you're about to get smarter in just a few minutes with Curiosity Daily from Discovery. Time flies when you're learning super cool stuff. I'm Nate.

And I'm Callie. 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.

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.

Without further ado, let's satisfy some curiosity. For decades, scientists have been trying to understand how you smell.

Yes, my aroma is complex. It's like fresh linens on a spring day with notes of Antler and

Okay.

Yeah.

Okay.

Making stuff up.

Yeah.

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.

Ah, okay. They've figured out how we smell as in like how we do the smelling.

That yeah.

Act, like how our sense of smell works.

You got it right on the nose. That's for smelling like elk antler. Anyways, 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.

An olfaction is just another way of saying sense of smell, right?

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.

Well right, and it turns out he who smelt it dealt it.

Now I'm pretty sure he who said the rhyme did the crime.

Scientists can't prove that.

Uh n 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 also 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.

It's kind of 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.

It's completely insane. And it happens with about four hundred 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.

I would describe Swiss cheese as having like a mild sour plastic aroma, but you know, that's just that's just my smell receptor.

Stinks on its own. 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.

You know, it's not my dream job, but somebody's gotta do it.

Yeah. So to model the meeting of the odor with the receptor, they used computer simulations and something called cryoelectron microscopy, a really difficult process that lets researchers peek into the atomic structure of those molecules so they could study their shape. Once they understood what they actually looked like and how they moved, they could model how the smell fit into the smell of the room.

Uh sort of olfactory meat cute.

For the stinky part of cheese.

So what will they do with this information?

Well, 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.

And maybe they'll finally figure out who dealt it.

I think we all know who dealt at night.

Blame me, I smell like linens and elk hamlets.

Or elk antler. Yeah.

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 its Way cool.

Why are you talking like a Kardashian?

That's my attempt at what's called vocal fry or creaky voice, and linguists have studied its use in people, especially the speech of young women. Well it turns out that dolphins, pilot whales, and sperm whales totally use it.

Two. I guess that's a sick.

Enough of that. Because this study is actually really fascinating because scientists have been studying the haunting vocalizations of whales and dolphins for ages.

And we've all heard those recordings, the eerie moans, the clicks, the whistles.

Yeah, all of that. We've known for decades that these sounds are used for social communication and echolocation. And they actually make different sounds in different registers just like we do. There's the falsetto.

The squeaks.

Yeah, 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.

So is that when they're just like totally hanging out, drinking some boba, sending snaps? Do people still send snaps?

I have no idea. But that would be quite a discovery. No, they use vocal fry when they're echolocating.

Oh, that makes way more sense. Oh, I'm sorry. Way more sense.

Yeah. 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.

Why was it so hard to figure out? I mean, couldn't dissections give them answers?

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 kind of get a sense of what it does, but you really have to see it to believe it.

So how do you see inside a whale while it's making the sounds?

That's a good question, and one that scientists have finally found an answer to. In the past, researchers have tried using x rays and sound triangulation to figure it out, but nothing worked until now.

That's a movie with quite a soundtrack.

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 created vibrations.

Isn't that how our vocal cords work?

Pretty much, yeah. But this study found that whales and dolphins actually need very little air to create those loud echolocation clicks. And that solves a problem that has befuddled scientists for a long time. How do they make sounds a thousand feet down and still have enough air to survive?

I never thought about that. But it would be pretty hard for us to make small talk underwater too.

Totally. With this new discovery, doctor Elemans thinks we have a route to recreating these sounds more accurately and gaining a better understanding of how these animals communicate.

Well that's pretty. Sweet.

I know, right.

You're much better at this than I am.

Lower voice might help, I don't know.

Well maybe.

Wait, what?

Yeah. His dad, William Henry Harrison, was our ninth president, and his son, Benjamin, was the twenty-third, and his body was stolen from its grave and sold to a medical school so it could be dissected by eager young med students.

Oh no,

Oh yes, this incident actually led to some major changes in the way cadavers find their way onto dissection tables.

You mean people back then didn't just donate their bodies to science?

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 our 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.

So if donating remains is a relatively recent thing, were all cadavers stolen in the past?

Not exactly, but it's 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 the body. I mean imagine getting your spleen removed by a surgeon who's only read about spleens on the internet.

Yikes.

Yeah. But for centuries, the idea of cutting open human beings was seen as sacrilegious and even, I mean, obviously revolting. So medical schools were often in short supply of cadavers.

Aha. Enter grave robbers.

As science and medicine advanced, the need for cadavers was so great and the supply was 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 it's grieving family, whatever.

So how did that change?

John Scott Harrison's body snatching helped put this into 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 sentence just to make the sentence a little worse.

Oh, as if execution isn't enough.

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 eighteen hundreds, when a trend took hold that would lead to today, people became more willing to donate their bodies to science.

What caused this change?

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 Abbey was telling readers to donate their body.

So there's just no more grave robbing? No.

There's no need. By some estimates, nearly twenty thousand people donate their bodies to medical schools each year in the US alone. Fortunately, the stigma has changed in the past two hundred years, and it's now viewed as an honorable, if not heroic thing to do.

Huh. Okay, one last question. Shoot. John Scott Harrison was really the son of a president and the father of one?

I know, it's crazy, right?

Let's recap what we learned today to wrap up.

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.

Marine researchers used an endoscopic camera to film dolphins making sounds from inside their navel cavities to finally understand the mechanisms behind the sound. 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.

While some twenty thousand Americans donate their bodies to medical schools every year today, that is a recent trend. In the mid nineteenth 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.

Curiosity Daily is produced by Wheelhouse DNA for discovery.

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