Adam's apple, the epiglottis that prevents food from entering into the larynx, and then a bunch of cartilages. There's a cricoid cartilage, and that connects the larynx and the trachea, and then there's a bunch of paired cartilages, the aratinoid, the corniculate, and the cuneiform. Okay, so the larynx has, hold on a second here. Okay, so here's the thyroid cartilage, which is the Adam's apple.
Now, this is definitely one way that you can visually see the difference between males and females. During puberty, testosterone not only affects the vocal cords in guys and makes them thicker and bigger, which causes that uncomfortable voice change that goes on during puberty, where their voice goes from being high to being low. It also affects the thyroid cartilage and you can visibly see that thyroid cartilage in the throat of most men.
Some men more than others. You can really see it in some guys. But you don't see it in women because we have estrogen.
We don't have the testosterone that's going to cause this to change in size. Here is the cricoid cartilage and this is where the larynx connects to the trachea. Everything below there is the trachea. So here you can see down here starts the tracheal cartilage and here is the thyroid gland, parathyroids on the back. Also note the location of the hyoid bone.
It's this way up there because remember it's going to be like up in here. It anchors the tongue and aids in swallowing and talking. If we look at the the posterior side we can see the the chroniculate cartilages, the arachnoid cartilages. What am I missing here? I did the cricoid.
I think I got them all. This is the cricoid cartilage. That is this guy.
That is the boundary between the larynx and the area beneath it, the trachea. Now notice on the trachea we have rings, okay? the rings don't go all the way around.
Back here, this part that touches against the esophagus does not have cartilaginous rings on it. Now the reason we have rings on the trachea is sort of like if you look at a vacuum cleaner hose, it generally has like little plastic rings that go all around it. That helps it not collapse when there's changes in pressure. it still stays open regardless of whether there's pressure or no pressure. And that's what these C-rings, they're called, do in the trachea.
They help to keep the trachea open regardless of changes in pressure. Okay. And so it's important that we have these C-rings lining the entire trachea. And you can actually feel them. If you rub your throat in the front, you can feel.
these ridges as you're going down your trachea, these C-ring ridges. Okay. All right.
So here are the false vocal cords or the ones on the top, and they're ventricular folds. And then down here are the true vocal cords, okay, the vocal folds. All right. And I'll show you a better picture of those.
The true vocal cord has skeletal muscle and elastic ligament called the vocal ligament. And when the muscles of the larynx contract, they move the cartilages and stretch that vocal cord tight. When air is pushed past it, the sound is produced and the longer, thicker vocal cord in a male produces lower pitch. The tighter the ligament is pulled, the higher the pitch is. And then to increase volume, you just increase the amount of air you push past it.
Think about the deep gulp of air you take when you're yelling. Here to the little bit. you're whispering okay so this excuse me the white part here are is the true vocal cords and on the sides is where we have those ventricular or false vocal cords so speech requires the pharynx the mouth the nasal cavity sinuses tongues and lips at tongue and lips to help form the words pitch is controlled by the tension so the more you pull on those vocal folds the higher the pitch is and then the less you pull on lower it is and then the volume is controlled by how much air you push past it. So this is what I was explaining earlier when you're swallowing a bolus or a lump of food.
As it's moving it's causing the soft palate to close off the entrance up into the nose and it's also causing the epiglottis to close off the opening to the the larynx. As soon as the food moves past there it opens back up. Laryngitis, inflammation at larynx. Cancer of the larynx is almost exclusively found in smokers, and I would put a little asterisk there and say, and also people who have human papillomavirus infections, okay, who are positive for papillomavirus. Human papillomavirus is the number one cause of cervical cancer.
makes about 90 some percent of all cervical cancers are caused by this virus that is out there. If you have had sex with more than one person, chances are you've come into contact with this, unless they are the only, unless you are the only person that those other people have come into contact with. Most of us in our lifetime will come into contact with papillomavirus. And there's two major groups. One group causes genital warts and one group causes cancer.
The ones that cause cancer don't cause warts. The ones that cause warts don't cause cancer. And there are some that are particularly bad in terms of cancer, like HPV 16 and 18 and 11, or not 11, excuse me, that's warts.
16 and 18 are big ones in the U.S. for cancer. And I know this because I worked on HPV for a while when I was still in the lab. A lot of what the lab I worked in did and a lot of the labs we collaborated with was HPV, human papillomavirus.
So it is the number one cause of cervical cancer, but it also is way up there in terms of being a cause of anal cancer. And we're seeing more and more and more cases of it. throat cancer that's caused by human papillomavirus infection caused by oral sex.
So this is why it's important to get your kids vaccinated against HPV. And some people are like, well, then they're going to want to go out and have sex. Like, really?
You think that's going to do it? You think that's why they're going to want to go out and have sex? I just think if you can prevent...
cancer, any kind of cancer. My gosh, if there were vaccines against lung cancer and brain cancer and all these other cancers, I'd be standing in line getting mine. So if you can protect your child against developing cancer, particularly something that's so endemic in our population, I mean, if you have sex with more than one person, chances are you're going to come into contact with papillomavirus. Most of us clear it. and have no problem with it whatsoever.
But in the people that don't, they're the ones that can develop cervical cancer and anal cancer and cancer of the larynx. My brother, my younger brother, died of, he had tonsillar cancer, which is type of throat cancer. And one of the first things they did was they did a test to see if his tumor was HPV positive, and it wasn't. But if it was, they would treat it differently than they would just regular throat cancer.
I mean, he smoked and he also drank a lot, and both of those play a role in developing different types of throat cancers. But it's something to be aware of, that there's more and more cases of throat cancer all the time being caused by papillomavirus infections. Okay, so the trachea is your windpipe, and it goes from the larynx to the primary bronchi. The C-rings help to keep it open, and just like it helps keep a vacuum cleaner hose open, having those rings going around it. And here you can see a cross-section through the trachea.
the trachea and you can see the position of the esophagus behind it. And if there's nothing in the esophagus, it's kind of like a vein. If there's nothing in it, it sort of collapses.
But here you can see the cartilage and actually in this picture that shows the thyroid gland right here. and this is going to help keep it open. It does not make a complete ring.
It only is shaped like the letter C. So this is about five inches long and an inch in diameter. And there are layers here of tissue and we'll see this when we get to the digestive system as well. You start with mucosa.
Mucosa is always the tissue that's going to face the opening. whether it's in the throat, whether it's in the esophagus, whether it's in the stomach, it doesn't matter where it is internally, this area here is mucosa. The area beneath is the submucosa, where sometimes you have glands and things like that. And then we have the cartilage, okay, and then on the outside is connective tissue called the adventitia that protects the outside of it as well as... attaches it to other organs.
The very last ring, ridge from the very last ring, is called the carina, and that actually is a landmark for the cough reflex. Okay, at that position, it splits into the primary bronchi. You have one bronchus going into each lung, and we have secondary bronchi. One goes into each of the lobes.
Tertiary bronchi, they branch off the secondary and each of those goes into something called the bronchopulmonary segment. And then from there come the bronchioles. Now the amount of cartilage that we have on these is going to go less and less and less until you get to the bronchioles.
Once you get to bronchioles, there's no more cartilage. All it is is smooth muscle and epithelium on the inside with smooth muscle on the outside. So if you suffer an asthma attack or if you have anaphylaxis, what happens is the smooth muscle constricts and you may have mucus or something else filling up the airway and you can't get air through it in the bronchioles.
Air is going to go through the trachea and all these other ones because they have cartilage holding them open, but it can't get through the bronchioles. And you get desperate. You feel like you're going to suffocate. You can't breathe. And that's why having an EpiPen for people who have anaphylaxis is so important.
Not only does it reverse the vasodilation of your blood vessels, it's causing your blood pressure to drop. It also... reverses the constriction of your bronchioles and allows them to dilate and open back up again so you can breathe.
Okay. All right. So this is showing the type of epithelium. We looked at that already.
Tracheostomy or tracheotomy is used to reestablish airflow if you have some sort of obstruction. It's also used if someone is intubated and they're going to have to be intubated for any length of time. Sometimes they'll do this in order to spare the vocal cords. Because here you can see if someone's intubated, it's pressing against the vocal cords and it can actually cause damage to them.
So if they have to intubate somebody for any length of time, they may consider giving them a tracheotomy to spare the vocal cords. So intubation can be used for anybody undergoing general anesthesia, if they're comatose, or if they're suffering from respiratory problems. Okay, this is the kind of picture I'd give you if I want to ask you about bronchioles and all of that.
So here's our primary bronchus, and you can see the cartilage on it. branches into secondaries. And again, there's cartilage, but you can see the cartilage is decreasing.
It's becoming more sparse as we go from secondaries to tertiaries. Here's our tertiaries. And then we go to bronchioles where there is none.
From the bronchioles, we go to terminal bronchioles. And then from there, we go to respiratory bronchioles. And then there's actually alveolar duct, which I forgot to... put on your list but alveolar duct and then these alveoli so these are the lobules