Jonathan Reisman: The Human Body - From Sex & Sperm to Hands & Heart | Lex Fridman Podcast #297

We have two tubes that are right next to each other in the throat. One is for food, drink, saliva, mucus, snot, whatever you're going to swallow. All of that stuff must go down the esophagus, the food tube, and end up in the stomach. And right next to the esophagus, millimeters away, is the windpipe, or the trachea, which goes down to the lungs, throat, heart, feces, genitals. Every organ from moment to moment keeps us alive and ensures our survival. The genitals are, in a way, the opposite.

How would you improve the penis and the vagina? The following is a conversation with Jonathan Reisman, a physician and writer of the Unseen Body, A Doctor's Journey through the Hidden Wonders of Human Anatomy. He has practiced medicine in some of the world's most remote places, including the Alaskan and Russian Arctic, Antarctica, and the Himalayan mountains of Nepal. This is the Lex Friedman podcast. To support it, please check out our sponsors in the description. And now, dear friends, here's Jonathan Reisman. You wrote a book called Unseen Body, all about the human body, the messy, the weird, the beautiful, and the fascinating details. So from an evolutionary perspective, are most parts of the human body a feature or a bug? Is it like the optimal solution or just a duct tape solution?

Great question. I think that most of the time, the way the body works is the best solution. I haven't seen many alternatives, so it's hard to compare, but I think there's some parts of the body that make more sense than others. The way our hands work, for instance, the muscles are up in the forearm and then the tendons kind of come down like strings on a puppet. And just the dexterity it gives our hands is just really amazing. And it's hard to imagine a better tool than the human hand to do everything from hold things to play piano and do a million other daily activities that we do. One thing I talk about in the book, there's some other body parts that seem to be lacking that kind of brilliant design, such as the throat, where the food drink are swallowed and air is inhaled, and those two paths come within millimeters of each other and you slip up once, you laugh while eating or you speak while trying to swallow and you die from choking. So it seems less than optimal, though I'm not sure it could be better. From the way we're kind of formed in the womb as a beginning, as this tiny little tube, I don't think it could have been done any better or there's any other way to do it. But it is an Unfortunate thing that does lead to some problems.

So the hand. If I could just linger on that for a second. You talk about the wisdom of a design in the book. What are the important things about the hand? It seems like very useful for many things and it seems to be quite effective. A lot of people think the thumb is foundational to the human civilization. Is there any truth to that?

I think that is true, actually. One of the ways in which the importance of individual fingers comes to attention is when people have severe injuries to their fingers. For instance, I have a story in the book about a guy whose thumb is nearly ripped off by his dog's leash. And, you know, when we. When plastic surgeons who are often the ones to repair that, sometimes it's orthopedic surgeons, they will debate, you know, how important is it to save this finger? Or how important is it to save, you know, let's say the kind of tip, the one third. The tip one third of one of your fingers. You know, it depends on the length that you'll lose. It depends on which finger. And so the thumb really is the most crucial just, you know, for your occupation, in most cases, to just daily life and your ability to get around, take care of yourself and others. So, you know, they'll be more. They're willing to go further, do more surgeries, more aggressive therapy to save a thumb, let's say, than, you know, the tip of your pinky finger. So in that way, I do think the thumb, you know, does seem like the most important in many ways.

It's nice that there's backups. I wonder if that's part of the feature or is it just the symmetry that nature produces? You think, you think the two hands is like, is it about the symmetry or is it about backup?

We'd be much less formidable hunters, gatherers, survivors in any way if we only had one hand. So I think that is important to have two. So we can, you know, even everything from kind of spearing an animal to firing a bow and arrow to butchering an animal, you, two hands to do it very effectively.

But can you do a better job with three?

Great question.

And we'll never know. Perhaps you tweeted. Now I'm going to analyze your tweets like it's Shakespeare sometimes. You tweeted that quote, millions of years of sex and death design the human body. It's like poetry. Are those two basic activities basically summarize everything that that resulted in humans on earth. So like, is it that. Is that a good summary of the evolutionary process that led to this conscious, intelligent being is death and sex, in a way, yeah.

So sex is how more of us get made, obviously, and death is how we get weeded out, or the gene pool gets weeded out and certain genes survive and others don't. And, you know, the age at which we die, whether it's before we've, you know, had sex and reproduced ourselves, is a big factor. And who survives, who doesn't, who passes on their genes and what the future of the body looks like, you know, who lived and who died before they were able to be at reproductive age a million years ago was pretty important in what we look like now. And perhaps how we have sex and die now will determine what we're shaped like. Unless technology has an even bigger role in that, you know, a million years from now.

So you as fundamental to, like, if there's alien civilizations out there that have the same order of magnitude of intelligence or greater, do you think that we will see something like sex and something like death? So the reproducing and this selection process, plus the weeding out of the old to make room for the new, is that kind of foundational to life?

I would think so. I mean, sure seems to be on Earth, you know, perhaps in some distant future when medicine is nearing, you know, perfection and people can live a really long time, maybe we won't even need to reproduce as much or something like that. You know, it's hard to even know what. What life will be like in the distant future. But I would guess that any alien civilization will have the same dependence on who has sex and who dies.

Well, that's the problem with immortality. How are we going to clear out the old to make room for the new, which is kind of. It's like a framework of adaptability to changing environments. So as long as the environment is changing, and it seems to always be because this, the entirety of the Earth system, is a complex system, it seems like you have to adapt. And to adapt, you have to kill off the stubborn old ideas. And unless there's a way to, like, not become stubborn and old. But it feels like the nature of wisdom is stubborn and old. Like, that's what wisdom is. It's like the lessons of life solid. The lessons of experience solidified. And the solidification is the thing that actually prevents you from reinventing yourself to adapt to the new, changing conditions. But then again, why not have that? Both those modes, like, have two minds and one person, one immortal person that, like, in the morning, they act like a teenager. In the evening, they act like a Old wise man. That's possible. So you can imagine within one mind both modes, but those are required. You have to have. You have to have the ability to completely reinvent yourself, which is what death does in an ugly way or a beautiful way, depending on your perspective, depending whether you take the human perspective or the human, the nature's perspective. And then you have to have the selection. So competition, so sexual selection. It's an interesting, interesting little planet we got. What's the weirdest part, function, concept, idea about the human body to you? We'll talk about fascinating details, but what's you, you, I should say for people that should read your book, they will come face to face with the fact that you do not shy away from the weird and the wonderful of the human body. It's like, it's fun, but it's honest. So given that, sorry to make you pick one of your children, but what's the weirdest one?

You say the weirdest body part or concept or function.

So the chapters, you divide it up kind of into parts, but there could be a thread that connects all of them. The weirdness, maybe, or maybe the texture of the substance could be the liquids, the solids, I don't know.

Definitely. Every body part and bodily fluid has their own kind of both gross and fascinating aspects. That's probably why I'm a generalist as a doctor and couldn't just, as you said, pick one of my children, become a specialist, because I like them all. I feel like one of the strangest concepts about the human body is that kind of the aspects of it that are the most universal, that we all do are the most taboo socially. I wouldn't have expected that if I had just looked from the outside. Like what we do in the bathroom, what we do in the bedroom, what we do to our own genitals, what we do to our private parts, they're private. Even though it's sort of the thing that we all have in common is the most we try to hide from other people and don't talk about in polite company. I mean, it makes sense as a human living in the society, but from the outside, it sort of might be surprising.

How do you make sense of that if you put on your Sigmund Freud hat? The thing we all do, why do we make that a taboo thing? Is it because we like taboos? Maybe we get off, maybe our kinks as humans is to have taboos and it's kind of efficient to have taboos about the things that everybody does. Like you can make walking taboo or something. I don't know. But just maybe that's what we love. That's what's exciting to us, is the forbidden.

I think, yes, society loves rules, for sure. Loves some societies more than others. You know, they love controlling how you think and what you do in public versus in private. You know, there's a lot of societies where, for instance, parents have sex in front of children, not, you know, for instance, like in a traditional Inupiat, Eskimo societies. That was sort of normal. I mean, but what are you going to do? Go outside in the middle of the winter in the Arctic and do it out there? Of course not. So, you know, there's different, different taboos in different societies. Some taboos make perfect sense. Some taboos are even public health measures. You know, like as I talk in the book about in, in India, where they, you know, the hands are symmetric, as you said, but in Indian culture, and the left hand is taboo, and the right hand is what you use for shaking hands for eating, for other things. And the left hand is the dirty hand that you use for wiping your own bottom. You know, that's the toilet paper is your left hand. So while the body is anatomically symmetric, the taboo creates this pretty intense asymmetry, but for a good reason. You probably shouldn't be shaking hands with other people with the same hand that you use to kind of clean your bottom. So in that sense, it makes sense.

Yeah, maybe the roots of it make sense, but the way it propagates, especially as the times change, might not because you can wash your hands, but the taboo remains, right?

Society is very slow to change.

What is the most fascinating part, function or concept in the human body? So, you know, something that fills you with awe.

I guess the most obvious one is the brain, partly because it's sort of poorly understood. Though we understand more than we ever have in the past, there's still so much that we don't understand about how the lump of matter in our skulls kind of creates this subjective experience that we all kind of understand quite viscerally. That's an easy one. I would say the kidneys are an underappreciated organ. The way they tinker with the bloodstream, raise levels of this, lower levels of that, kind of our entire lives from inside the womb until we die is just really incredible. And when you look at how much energy different organs consume, the brain and the kidneys are two of the biggest ones, because the brain, obviously in us, is always active and controlling parts of the body, but the kidneys are just consuming a Ton of energy to do what they do. They're kind of the unsung hero of the body, relegated to the back of the abdomen like some forgotten organ. But they are great. I did consider being a nephrologist, which is a kidney specialist, because I was so taken with the kidneys, but decided I like all the organs, so couldn't pick just one.

So your book is ordered in a particular way. It's throat, heart, feces, genitals, liver, pineal gland, brain, skin, urine, fat, lungs, eyes, mucus, fingers and toes, and blood. All right, first of all, great, great chapter titles. Is there a reason for this ordering or is it all madness?

There's a few different reasons that went into it. I did want to start with the throat for the reason that it kind of presents the topic of death, which is sort of obviously very important in the training of a physician, in the career of physician. It's a big part of what I deal with. On the first day of medical school, we started the dissection of a cadaver in the class called anatomy lab. And so in a way, we were kind of thrown right in there in the beginning, like, this is the end of the human story, you know, understand this. And then we sort of backed up to the beginning with embryology and reproduction and stuff. So it's kind of like we got. And I got thrown into that right, right away, right in the beginning, kind of like, here's a dead body now. Start cutting it apart and learn the name and function of absolutely every bit of flesh.

How did that change you, that first experience with the cold honesty of human biology?

Right, that's exactly what it was, is cold honesty about the kind of. The story of, of each individual human body. It has an end. And that's it. I think that. Well, actually before the end of that first day. So what we did on that first day was study the superficial muscles of the back, like the lats or latissimus dorsi and some other muscles. You know, we cut through the skin of the back. My cadaver was laying face down on this metal gurney. We pulled back the kind of plastic sheets that would keep him moist for the next four months as we dissected him, cut through the skin on his back, and then started dissecting through the superficial muscles of the back. And that was really all we saw that first day. We didn't get any deeper, didn't enter the abdominal or chest cavity to see internal organs. But I was so fascinated with this sort of behind the scenes look at how things work in the body, how you move your arms, how you arch your back, you know, these are the muscles that do it. That I decided I wanted to donate my own body for the same purpose. So I made that decision literally before the end of that first day of class. And I. I'm still sticking to it.

So someday there'll be a medical student that can watch and listen to this podcast while dissecting your body.

It could happen. They might not know that that person they're listening to on the podcast will be the carcass in front of them. But, like, we don't. We never learned.

The universe will know. The universe will know, and they will acknowledge the irony or the humor, the absurdity of that.

The universe will chuckle, but the medical student won't know, because they never, as I did not learn any, you know, personal information about the person, only what I could glean from looking inside him. Which actually tells you quite a bit. I knew he was a smoker. I knew he had coronary artery disease. You know, you get a window into. I knew he was overweight. You get a window into people's lives just by looking in there, in their bodies, after death. Other. Other cadavers in the lab, not my own or I shared one with three other students, but other cadavers. Some had, you know, metal joints, like a knee replacement. Some had a kidney missing. So they probably. And we could tell it was surgically removed, not that he was born with one. And you could tell that he probably had a kidney tumor or cancer that was removed. So you do get an insight into people's lives from, you know, picking them apart after they're dead, but you don't know their name or what podcast they've been on.

So the, as the book title says, unseen body. So it tells some kind of story of your life. So it does capture the decisions you've made in your life, the things you've done that might be kind of secret to that person and maybe to a few others that knew him or her well. That's so fascinating. So what kind of things can it reveal? Like, what kind of choices in terms of the injuries, the catastrophic events, the lifestyle, choices of smoking and diet, and all those kinds of things. What can you see? What kind of history can you see about the human before you?

So all those things you mentioned are things you can see. Take the skin, for example, right? Most things that happen to us leave a mark, you know, as I say, a kind of a story written in the language of Scar, where it tells you injuries you've Had. And same thing with animals. You know, I've. I've seen deer hides that have marks that look like they're made by maybe a barbed wire fence, something like that. You can tell, you know, you. Sometimes it's conjecture, but you can sort of imagine what might have happened to cause that perhaps, you know, two bucks were fighting and one got injured with an antler. And the same with humans. You know, I have scars on my body, and when I notice them, I remember what happened. You know, I got a big cut on my hand when I was 13, and it's still there. And I remember what happened, you know, every time I look at it. And so in that way, only I might know that story. But other people, you know, when they dissect me and notice the same scars, they can kind of. It can fire their imagination as my cadaver, you know, did for me.

They know that there is a story there that's such an interesting way that the skin does tell a story, both tattoos and scars, right? Some of the fun you've had and some of the damage you've done, right?

And even when I. When I evaluate a patient, I can use scars to help me make medical decisions. So, for instance, someone comes in with abdominal pain into the emergency room. You can see scars on their abdomen that tell you about, you know, the past kind of activities of a surgeon, perhaps. I know, I recognize the scars that are left when someone has their gallbladder removed, the scars when someone has their appendix removed, when maybe when someone's had a hysterectomy. And that can tell you what it might be or what it isn't. You know, if someone doesn't have an appendix, their abdominal pain is not appendicitis. End of story. So in that way, I'm sort of looking at these, the. The tracks or the footprints of past surgeries to tell me what. What might and might not be the cause of this patient's abdominal pain, which is kind of. My main job in the ER is figuring out what's causing it and to help them.

Is there ways to get more data about the human body as we look into the future of medicine biology? That would be helpful to fill in some of the gaps of the story. So, you know, you have companies, you have research that looks at collection of blood over long periods of time to see, sort of paint a picture of what's happening in your body, mostly to help with lifestyle decisions, but. But also to anticipate things that can go wrong and all that kind of stuff. Can you just speak to A greater digital world that we're stepping in, how that can help tell a richer story.

I certainly think that we have more data than we know what to do with right now, especially with direct to consumer medical devices, smartwatches, et cetera, that are just collecting these reams of data. I have not seen them put to. I think the eventual use that they will. I think that the potential is sort of just, you know, unimaginable. And I hope we're heading into a new age where, you know, you can determine, for instance, is a person going to have more of the dangerous side effects to a drug based on their genetics, or are they going to tolerate one drug better than the other, you know, based on their genetics? And we are slowly moving into that age, and especially the age of kind of completely synthesizing drugs in a lab. You know, much like, for instance, some of the COVID vaccines, actually, like Moderna never had the virus in their lab. They made that vaccine completely without ever having the virus themselves, just by having the genome, which is sort of astounding. And there's a lot of potential going forward, you know, based on that technology and some others.

I didn't know that. So they basically. It's all in the computer. It's computational, right?

You have the genetic code. You have tremendous power, even if you don't have the organism itself.

What do you make of Elizabeth Holmes and efforts like that? First of all, I am a curious. I'm drawn to the darkness in human nature because that somehow reveals the full spectrum of what humans could be. So there's a lot of sort of controversial thoughts about who she is and her efforts and so on. I think you may have even tweeted about it, but I've read a lot of your tweets. I'm now forgetting, but what do you make of her and those, both those efforts and the charlatans, that sort of snake oil salesman that promised those efforts to do more than they currently can.

I think that her, you know, that goal that she had, that she created Theranos to try to achieve, to use less blood in tests, is a very worthy goal and a huge frontier that we have not achieved and that I hope we will achieve. So I understand why. You know, someone describes what a huge step forward that would be, and it would be, indeed, I understand why people put a ton of money behind it.

Can you describe what was the promise? What are we even talking about? What's Theranos? Just for people who don't know.

So Theranos is a company that was Basically started to revolutionize the way medical blood tests are done. Both to use a whole lot less blood in doing it. If anyone's ever been to the doctor and had five to 10 tubes of blood removed from them, it can be quite surprising how much they take out. Uh, and. And it's, you know, that's the limitation of our technology, that we need those volumes of blood to run all the tests that we want to. And so the promise of Theranos was that perhaps with a single drop of blood, we would be able to know as much about the person's. The condition of their. Their body without drawing all that blood. And. And thereby, you know, there would be these devices she was going to create that would sort of do it. You put a drop of blood in and spits out everything you ever wanted to know about what's in your bloodstream. And in a way that would make it so much easier. You know, it could be. You could have one in your home, theoretically, and you. I don't know why you'd wonder what your potassium level is on any given day, but you could check if you wanted to. And so that. That goal is very worthy. You know, I. I put that goal up there with the. The frontier of making painkillers that are as good as opioids without the addictive quality. You know, that would be such a huge revolution if we did have that in medicine. But. And particularly for me, because I trained in both pediatrics and internal medicine, so I learned to care for both children. And in children, we do draw much less blood. They have a much lower blood volume, and we use these tiny little tubes to draw their blood, and we seemingly get equivalent information out of the larger tubes we draw from adults. And I'm still unclear, to be honest, why we can't draw that little amount of blood from adults. It seems technically possible. I don't know what the barriers are. I'm sure there are, or else we'd be doing it. But I do think that that is a very important goal. And if Theranos had done it, they would have really revolutionized the practice of medicine.

So to return to that cadaver, that first day when you got to meet with the dead, with a human body that's no longer living. So how quickly did it take for you to get used to sort of, you said, looking at the surface muscles of the back, I mean, that can be overwhelming as a thought. And people listening to this that have never dissected anything might. Might be overwhelmed by that thought. So, like, how quickly were you able to get used to the brutal honesty of the biology before you.

For me, it did not take long at all. I guess I've never been a squeamish person. So for me, it was kind of riveting and fascinating right from the first moment. But I do know some of my fellow classmates did have some trouble with it. Some of them, I heard, had nightmares in the first few weeks of anatomy lab, and. But then everyone, as far as I know, got used to it. And that was also actually a big lesson for me that it's pretty amazing what people can get used to in their daily lives. And I kind of extrapolated that to people living through war and through, you know, just terrible situations and living under, you know, oppressive regimes. And it really is amazing what people can get used to. Almost anything.

But, you know, in war, people often come back and they have nightmares, they suffer through it. There's ptsd, there's. There's a lot of complicated feelings with that are echoes of those same complicated feelings possible in the case of training to be and becoming a doctor.

That's a good point. Yeah, I think, you know, sometimes, just as, you know, a barbed wire fence can leave a scar on your skin, you know, emotional psychological experiences can leave a mark on your brain or your memory. And I think that that definitely could be a problem in medical training. You do see a lot of things that are very shocking, very repulsive things that you'd never forget. I know one of those students that had nightmares initially went on to be a surgeon, so I imagine she's not having the PTSD of kind of seeing inside her first dead body, because she sees inside them all day, every day now. But I'm sure it could. We go on to see so many kind of grosser or more shocking things in medical training, through medical school, and then by working with actual living patients, not just dead and embalmed bodies. So I do think that things can leave a mark, but I don't think that initial cadaver would be the most traumatic.

Yeah, but maybe some of that trauma, the demons, make you a better surgeon, just like some of your own psychological trauma might make you a better psychiatrist. Returning to the ordering. Is it order or is it chaos? To the ordering of the chapters, from throat and heart and feces and genitals all the way to fingers and toes and blood.

So I did mention that, you know, throat was the first one because I kind of wanted to throw the reader right into the brutal honesty of death. And I followed it up with feces as the third chapter In a way, partly to also throw them right into the deep end of how I like discussing parts of the body and revealing their gross and fascinating aspect. So I didn't want to hide anything. You know, when you train to be a doctor, everything is on the table, literally in the cadaver lab. But also just, you know, you deal with blood and piss and vomit and feces, and that's kind of the medium of your craft and.

Yes, the medium of the craft. That's right. Right. Like, if you're a painter, this is the paint.

Exactly.

And then you have to create a masterpiece with it. Like, almost like a dance, because there's multiple painters. One of the painters is the biology. So let's return to throat. You mentioned. It's a weird one. So, first of all, a friend of mine said, I just see humans as, like, a bunch of holes that just walk around.

Not untrue.

Funny way to look at humans. So we have ears, we have nose, we have mouth, we have the sexual holes. Vagina, penis, and then, you know. What's the medical term for your asshole?

Anus.

Anus. Thank you. This is a very technical discussion.

The rectum's further in. Don't confuse the two.

Oh, that's very important. Is there a difference between throat and mouth, by the way? So when you say throat, are we talking about when that hole actually becomes tubular?

So the throat, I would count as just sort of the very back of the. Of the. You know, the back of the mouth, where the nose also comes down and meets it, where the tonsils are and the uvula. But you're right that, you know, we are a bunch of holes. But more accurately, we're a tube. Right. We start in the womb as kind of this microscopic little disc, almost like a. A, you know, a flatbread. And then we're. We roll almost like a burrito into this tube, and we're a simple, microscopic tube. And from there we grow into this bigger and bigger tube, and we become more complicated. And each end of the tube does split into various holes. So all the holes you mentioned, at the front end of the tube, the front end of our body, right, it splits into the nose, the mouth, the ears, the sinuses, the. The tube to the lungs, which is the windpipe, the tube down to the stomach, which is the esophagus, and then the other end of the tube splits as well. You know, men end up with two holes, and women end up with three holes, you know, the urethra, the vagina, and the anus. And men just, you know, the Urethra and kind of the reproductive system, they share a hole.

So I'm learning a lot today. It really is incredible that you start from sperm and an egg and you have some DNA information. And from that the building project begins. And then what that leads to is like a. Like a. Like pizza dough. And then you roll it into a tube. And that tube then eventually sort of becomes more and more complicated and gets eyes and a brain and then can create a Twitter account. It's really incredible that we're just a fancy tube, right?

We are. And we sprout eyes and a brain and a sense of smell and taste pretty much to regulate what comes in the front of the tube. You know, we don't want to eat anything dangerous or poisonous. You know, we want to choose what we eat, even choose who we kiss.

Well, we seem to be motivated by what comes out of the tube as well. In part, that's not just output. It's a feedback mechanism. Seemingly like we're also monitoring the functioning of the output. We're not just obsessed about the input.

We'Re very obsessed with the output. You're absolutely right about that. People have medical complaints about their output very often that are. I never cease to be surprised by a new kind of complaint or observation about the output.

I think people have gone to wars over the output and maybe sometimes the lack of the output or the desire for output with particular other humans that you fancy. The brain and the eyes that sprouted somehow convinced the rest of the body that this one particular other tube is fanciful. So you're going to go to major wars and lead global suffering because of the fancy and the desire for additional output with the other tube. Okay, so that's so on the throat. That part of the tube, is it. You said the design is not. You could have thought of maybe a little bit better options because it's too multifunctional. Is that. Can you sort of elaborate on the multifunctional nature of this part? Are a lot of parts of the human body multifunctional, or do you find that more specialization is going to get the job done better?

There is a lot of organs, for instance, do have multiple functions. You know, the pancreas has two, is like two organs in one. One secretes hormones like insulin into the bloodstream, and the other aspect of it secretes digestive enzymes into the gut to help you digest and absorb food. The liver is like 15 organs in one. It's just amazing how many different things it does. But the throat, you know, so basically the Problem with the throat is, as I said, we have two tubes that are right next to each other in the throat. One is for food. Dr, Saliva, mucus, snot, whatever you're gonna swallow. All of that stuff must go down the esophagus, the food tube, and end up in the stomach. And right next to the esophagus, millimeters away, is the windpipe or the trachea, which goes down to the lungs. And your, your throat does these daily gymnastics to keep everything but air out of the windpipe because, you know, you slip up once and you can die, you can choke, you laugh or speak while eating. And it's curtains, unfortunately. So it seems like every aspect of the body, when I was learning about it in med school, seems so brilliant and so perfectly designed by evolution or whoever you might think designed it to favor survival, to enhance life. But the throat seemed the opposite. It seemed set up almost for failure. And, you know, we developed all these mechanisms as a compensation, right? We have the gag reflex. Whenever food or something is headed towards your air pipe, your windpipe, or down to your lungs, your throat has this sort of like, rejection of it. It pushes it away in a gag reflex. At the same time, we have a cough, which is something our body does when something inappropriate does get down the windpipe. You know, when we get a little food down the wrong pipe, we end up coughing, and the coughing does usually flush it out and get rid of it. We even have something called the mucus elevator in our lungs, which is this constant flow of mucus up the airways up to the trachea, dragging with it all kinds of particulates that we've inhaled and perhaps some food that went down the wrong pipe and drags it up into the throat and we swallow it kind of unconsciously all day, every day is the truth. Even the mechanism of swallowing is super complicated. It uses a number of cranial nerves. It's uses over 15 different muscles. It's this coordinated act to keep food out of the airway. You know, you can see someone's Adam's apple in their neck kind of jump upward when they swallow, which helps lift the airway up against this kind of the epiglottis, which plugs it closed and allows food or swallowed drink to kind of skirt just past it. But every time we swallow, those things do come within millimeters of going down the wrong pipe. And it's just thanks to these kind of compensations, these adaptations we have to the danger of the throat that that keeps us alive.

As I actually took a sip of Water, it's kind of. It makes you appreciate the wonderful machinery of it all. By the way, we have pulled up your Instagram that people should follow. You have a post about the throat and just showing so many different components from the tongue to the trachea, the esophagus, just the entire machinery of it all the teeth for the chewing. It's so interesting. And so a lot of the structure of this, the anatomy and the physiology, does it echo other mammals? Are we. So are we just basically borrowing a lot of stuff from evolution and maybe making small adjustments, maybe due to the fact that we're not using our mouth to murder things as other predators might? We use our thumbs.

Exactly. We have hands. We don't need to bite them. Yeah. There's a lot of overlap between different animals, which I find very comforting and fascinating. You know, someone asked me, is there any animal in which the throat is better designed? And my first thought was whales, because the blowhole's kind of up on the top of their head. So I was thinking, oh, maybe, maybe they are set more separate. But when I looked into it, actually, no. You know, the paths do come very close, just like in us. And I saw a paper about some new discovered organ that actually helps keep food and drink out of the airway in whales that they hadn't ever noticed before. So it's a different mechanism, but the same kind of basic problem is that, you know, where tubes and the air tube and food tube are right next.

To each other, how well do we understand. So just even lingerie in this little part? And is there still mysteries about the complexity of the system? Because you mentioned just even for swallowing, all these parts in the brain that are responsible and all the different things that have to, like an orchestra play together, do we have a good sense from both a medical perspective and a biology perspective, or is there still mysteries?

There's definitely still mysteries. We understand a lot about, for instance, how the swallowing mechanism, you know, is coordinated. It's in the brain stem, sometimes using some higher levels of the brain. But it is a very thoughtless thing, as you mentioned when you drank the water. You know, it's not something we have to think about, thankfully. We'd be thinking about it all day. There's a lot we don't understand about the basic mechanisms, perhaps about how the nerves fire and.