When you're enjoying a tasty beverage or maybe chowing down on some crackers or something along
those lines and it goes down the "wrong tube"... it's literally going down the wrong tube!
There's only two to choose from, and it just happened to take the wrong pathway.
Now to understand why and how this happens, we first need to take a look at some of the
important relevant anatomy, and that's exactly what you're seeing here in this mid-sagittal cut.
Our story is going to begin — probably unsurprisingly to you — here in the
oral cavity or what most people would just refer to as the mouth.
Now you can see that this massive structure here
known as the Tongue, takes up the majority of your oral cavity.
You're also going to find teeth and mucosal membranes are also going to reside inside of here.
Then up top you have what many people call the roof of your mouth,
but this is actually what's known as the Palate.
There is a Hard Palate and a Soft Palate.
Technically these don't really reside inside of the oral cavity — instead they separate
the oral cavity from the nasal cavity, but still it's important to our story.
Let's go ahead and say that you're taking a swig of your favorite tasty beverage,
and as you do that, it's going to enter — obviously —into the oral cavity.
That Tongue is going to then push it back, and this Soft Palate here
is going to help guide it into the next "player" of our story or game.
This is what's known as the Pharynx.
Now technically this is only one part of the Pharynx.
The Pharynx actually has three different components to it.
This upper portion is what's known as the Nasopharynx.
This is also going to be unsurprising to you
because the Nasopharynx comes into contact with the Nasal Cavity.
Then the Oropharynx is also once again or should be unsurprising to you, because the
Oropharynx comes into contact the Oral Cavity. Down here, this next structure is what's called
the Laryngopharynx, and it kind of runs into this flap here that we'll talk about in a second.
The flap is not part of this — instead it's just going to be this space above the flap.
The Laryngopharynx gets its name because it comes into contact with what's known as
the Larynx, and that's this structure here which includes this little flappy thing.
The Larynx — most people would refer to as
the "voice box", and that's because it has vocal cords.
This is where vocalization or pitch control is going to be happening primarily.
So again, the fluid is coming down and it's going to get diverted by
this Soft Palate into the Oropharynx,
and it's then going to come down and it's going to literally run into this flappy thing.
This is the most important "player" in our story or game.
This is what's known as the Epiglottis,
and the Epiglottis is one of the most unique tissues in the entire human body.
That's because it's made of something called Elastic Cartilage, and only one other thing
in the entire human body is made of Elastic Cartilage and it's going to be this floppy
thing on the side of your face here that helps you hear — that's your Pinna or your External Ear.
I'm not going to touch it because obviously I've been touching some preserving fluid,
but if you were to pinch your ear and kind of move it around,
as soon as you let go it's going to pop back into place.
That's because Elastic Cartilage is there to retain its shape no matter what.
Your nose for instance is actually made of a
different type of cartilage — it's called Hyaline Cartilage.
Hyaline Cartilage also retains its shape pretty well, but that's not its main job.
Its main job is to actually reduce friction.
If you push your nose to the side and like held it there — I don't know why you do this — for like a
half an hour or so, when you let go it would still be slanted to that side but if you pinched the ear
and did that same thing it's going to bounce back in a half an hour.
The same exact thing is going to happen here in this Epiglottis.
The reason why it needs to be able to retain its shape is because it has a very important function.
If I push it up you can see that there is a pathway into the respiratory tract.
Let's say you were breathing — the air would come in this same pathway and
the Epiglottis would be up and the air would go in and then pass down through
the Larynx and into this structure which which is known as the Trachea.
Let's say you're eating or drinking — what should happen is this should come down and block it off,
and that then allows the food or drink to go down
this tube right here which is known as the Esophagus.
The Esophagus is part of your digestive tract.
The Trachea, Larynx — these are part of your respiratory tract.
The entire purpose of this Epiglottis is to protect
the airway from getting food or drink traveling inside of it.
Let's go ahead and talk about how the Epiglottis even
comes down to protect the airway in the first place because it's actually pretty interesting.
Again, when you are swallowing that liquid — when it hits the Epiglottis,
that is going to assist in actually pushing it down.
But it doesn't do the entire — or take it the entire way.
Another thing to take into account is that there's a bone right here called the Hyoid Bone.
The Hyoid Bone has muscles attached to it that are essential for speaking and swallowing.
When you're swallowing, it's going to pull on the Hyoid Bone,
which is going to put tension on the Epiglottis, which is also going to help to bring it down.
I don't know if you're really going to be able to see it, but there are muscles — well
you're definitely not going to be able to see the muscles — but there are muscles here on the side
of the Epiglottis that are also going to help to contract and pull this thing down.
When you add all of those up you are going to get a blocking of that airway.
So then the question really is, "what's preventing it from happening"?
If you were to — in the name of science — pay attention to what you were doing
the next time this happens, more than likely
you breathed in, or you laughed, or did something very quickly that caused this.
Because the thing that causes it to come up — because if this stays down when you're trying
to breathe, air is not going to be able to go in and out of your respiratory tract.
That's why you're only able to do one of two things — you're either
breathing or you are swallowing — you can't do them both at the same time because that
would require this to be open and then you would have it go down the "wrong tube".
This is the exact location that it goes down the "wrong tube".
Instead of going down the Esophagus, it goes down into your respiratory tract.
If you laugh, if you hiccup, if you get startled, if you just take a breath in for some reason
then... you can get this to go in, and when it does you get a pretty intense response.
You get what's called a cough reflex.
The cough reflex is there to protect you.
There are neurons inside and lining this entire area that are receptors.
They will sense when something is going in there other than air and it will cause a reflex
that will shoot up through a pathway we can't see here, that'll go up the spinal cord and
go into this area here — if I can pull this into frame — called the Brain Stem.
What's going to happen is the Brain Stem is going to be like, "hey! That's not supposed to happen!"
It's gonna send neurons down to the breathing muscles, like the Diaphragm and the Intercostals,
and it's going to cause them to contract and you're going to start coughing like crazy.
Because as you cough, what's going to happen is air is being pushed aggressively out.
What will happen — hopefully... the idea here is that the drink or the food particulate — whatever
it is that's going down this pathway, is going to get pushed out, and you are going to cough it out.
Even if it's a very small small amount of liquid
or a small piece of food particulate, that's going to cause a pretty aggressive response.
The thing is, if it does make its way down here you're going have a pretty significant problem.
I can even show that with this dissection right here.
To wrap your mind around what you're looking at here,
this is going to be the Larynx or "voice box".
This piece of tissue right here is known as the Thyroid Cartilage,
but most people refer to it as the "Adam's Apple".
This purple gland right here is called the Thyroid Gland — it just rests below [the Larynx].
Then we get to the Trachea.
Now the Trachea — this is actually pretty cool... let's see if I can hopefully get this on camera.
I can "accordion" it.
That's because there are some cartilaginous rings with connective tissue in between.
Now picture this as your coughing — it's like...
*Coughing Noises*
Hopefully that came across on the camera.
Let's go ahead and say that the particulate or the food does come down here
and what we see is there is a splitting into the Right and the Left Primary Bronchi.
Now what you'll notice is that the left actually has a bigger degree of change.
Its angle — that is changing — is going to be greater than on the right side.
That's because the Heart is on the left, so it has to make its way around the Heart.
That means if something does fall down, it's more likely to go into the right side.
I also want to show you this...
If I swing the Trachea to the side, you can also see that other tube
which is the Esophagus that it should be going down.
I actually have another dissection,
so let me go ahead and grab that so we can further illustrate this point.
So as I get this in frame here, you can once again see the Larynx, and we can see that Trachea.
It comes down and you can again see where it splits — so we've cut this.
You're looking at a right lung, because the left has been cut.
Let's say that the particulate would go here.
You can again see how it's much easier for it to go on that right side,
but if I pull it over here like this — again let me get this in
frame as best I can — you can see that this is going to continue to branch off.
Depending on what you swa— at this point it's not a swallow... it's what you inhaled...
If it's a liquid, it's going to be able to go all the way down to the
distal end of these tubes which is going to branch an obscene amount of times.
It's going to branch and branch and branch and branch,
and it's going to permeate the entirety of the lung tissue.
If it's a food particulate, it really depends on how big it is because if it's big enough
to make it past this spot but not big enough to make it past — I don't even know if you can see
this — make it past this spot, it might get jammed here and that can create a pretty big issue.
Think about this — your lungs are not designed to digest and break down and absorb food or drink.
You don't have the digestive enzymes to be able to pull this off so you have a
pretty big problem when you have something entering into this space
and there's no real ability for your body to break it down.
We call this Aspiration, and that's the real — I guess when we're talking
about something going downn the "wrong tube", you are Aspirating.
Now there is degrees of severity.
If it's just barely goes into the Larynx, then you're going to quickly cough it up.
If it goes all the way down, that can and is likely to be a more intense scenario.
It really just depends.
What can happen or what will happen, is your body is going to respond through coughing, for sure.
But your body's also going to recognize that something is here that doesn't
belong and that's where you're going to start mounting an immune response.
This is going to come with inflammation.
We call this inflammation
Pneumonitis, and that's just going to be an inflammation of this tissue here.
You can picture throughout all of the space
that these tubes have permeated, all of that is going to start to get inflamed.
Well, maybe not all of it...
Wherever that Aspirated material is at, is going to start to get inflamed.
Now a type of Pneumonitis is actually Pneumonia.
But Pneumonia is an infection, and this isn't really an infection.
Although it can be!
You can get Pneumonia
from this, because you also have to understand that you are covered in bacteria.
I'm going to have to do an entire video on the microbiome..
I'm completely obsessed with it.
You are covered in good bacteria or just bacteria that is performing some kind of function for you.
That includes the inside of your respiratory tract — there's going to be bacteria in there.
The thing is, if you actually provide some of them — some of those species might able
be able to use whatever you inhaled as a food source and that can cause them to multiply.
If they multiply that can create an infection that you then can have Pneumonia.
Or maybe the bacteria was bacteria on the particulate that you inhaled.
That itself could possibly create Pneumonia, but by far and large you're going to get
Pneumonitis at the same time.
Let's say it's a piece of food and it blocks this to such a significant degree,
at that point you have what's called Asphyxiation and you are now going you're suffocating.
That can obviously
kill you and that's because you're no longer able to exchange oxygen and carbon dioxide.
You can see that going down the wrong tube is a pretty big problem if you block off this area.
If I go ahead and bring this back into frame here... look at this.
We have that Epiglottis again.
Look at how important this little thing is!
You can now see again why it's made of Elastic Cartilage, and why it's
such a big deal for it to come down here.
Again, I hate ranking, like "this piece of
tissue is more important than this piece of tissue and..."
They're all important.
But I think you all can respect just how important this little flap really is
because it's saving you from all of the Aspirating
and all the stuff you do every single time you take a drink or you are eating.
If you want to better understand how the various organs and tissues
interact with anything that you ingest, whether that's through inhalation, digestion
or even topically, like on the skin — it's best to think of the body as a gigantic puzzle.
In a strange way, anatomy is very similar to watchmaking.
There are countless structures all interacting with one another to create
this gigantic superstructure that we call the human body.
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Brilliant allows you to explore the depths of subject matter such as engineering,
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Just understand — analytical reasoning will carry over into
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