- [Instructor] Here we are looking through
the respiratory system.
We're looking at the different.
First off, what is respiration?
Respiration takes into account
several different things.
First off, breathing, the movement of
air into and out of the lungs.
It's as simple as the air goes in,
the air goes back out, but what's really
interesting is what happens to that air
when it goes into the lungs.
Once in the lungs you start with your
external respiration.
Your external respiration is when
you oxygen, O2, and carbon dioxide, CO2,
exchange between the lungs and the blood.
The blood is going to take in oxygen
while the blood gives off carbon dioxide
to the lungs, so this external respiration is where
the respiratory and circulatory systems overlap.
Then you've got transport.
You can carry the oxygen away from
the lungs down to the tissues.
You can carry the carbon dioxide from
the tissues back up to the lungs.
While we're in the tissues, we have this
internal respiration.
Internal respiration is where an exchange
in the gases O2 and CO2, so oxygen
and carbon dioxide, between systemic blood
and the tissues.
What that means is, your blood will be
giving off oxygen to tissues,
things like muscles or our stomach,
while the blood will be picking up carbon dioxide.
So you have this two sided thing.
Can't we talk about respiration
without dealing with the circulatory system.
Then we have what's called cellular respiration.
Cellular respiration is what's being used in the cells.
The oxygen itself is being used to make ATP,
your energy source.
As you make the ATP the carbon dioxide is
used as a waste product.
Here is our respiratory system.
What you're seeing is the upper respiratory system
starts with the nose.
That's how the air gets in.
But is that the only way for air to
get into the respiratory system?
No, because you go through the nose
to these nasal cavity, kind of filtering
and warming, helping to clean stuff out
down to the pharynx which is part of the throat.
But don't forget, the mouth also
connects to the throat.
That means both the nose and mouth
are able to bring in air.
Now, it's usually more beneficial to
bring air in through the nose
because this way you have a chance to warm it op,
you have a chance to filter it,
it just really helps to get things ready
for the lungs.
Once you've passed through here
you go down past the epiglottis.
The epiglottis is meant to protect,
prevent liquids and solids from getting
down in the lungs.
You get down to the rest of the lower respiratory tract.
The larynx, that's where our vocal chords are.
The trachea, it a big tube that carries
air from your upper respiratory down to the lungs.
Once you're in the lungs, that's where
you have all these individual alveoli.
That's what's actually causing gas exchange.
Before you get to the individual parts
you go from the trachea into the bronchi.
They're branching pathways.
Bronchi eventually get to the alveolar air sacs.
Everything is kept protected by the rib cage.
It helps to keep it protected from external,
but also helps with the actual process of breathing.
Pleural membranes.
Your lungs are going to have
a double membrane system around them.
They have an outer and inner pleural membrane.
It helps prevent friction damage as the lungs move around.
Then we have some musculature,
intercostal ribs with the diaphram.
These muscles are what cause the lungs
to actually expand in size.
It allows them to expand in size
and therefore they can help and bring air
into the system.
Now that we've seen the structures of
the upper respiratory tract, let's figure what it does.
First and probably most obviously,
it's a passageway for respiration.
It's a passageway to get air in,
but you also have your smell receptors.
This is where you find the ability to
smell pretty much anything in the environment.
Now are our smell receptors as sensitive
as a dog's?
No, but we have a different variation,
with these filters.
Do you ever wonder what the point of
those little hairs in your nose is?
They're filters.
They help prevent larger objects from
getting into your respiratory tract.
It's not just little hairs.
You also have mucus, and mucus is meant to
trap different microorganisms, trying to help
prevent them from getting down into your lungs.
It moistens and warms the incoming air.
Have you ever been outside on a day
when it's zero degrees out, nice and cold?
Well, zero degrees Fahrenheit, if you take
a big gulp of air through your mouth,
you might feel it down in your lungs.
Your lungs might feel a little bit cool, a bit tight.
But you do the same thing, a big inhalation
through your nose, it won't feel the same way.
The nose allows the air to pass through more membrane.
It allows it to get warmer and gives it more moisture
so it's better for the lungs when it gets down there.
Voice, how do you create your voice?
It's air rushing past your vocal chords
and then bouncing around your mouth,
your nasal cavity, creating all different sounds.
Here you can see the tongue, external nose,
the sinuses up top.
Let's fill the gaps in here.
Through the nostril, that's how the air
gets into the upper respiratory tract.
Nasal cavity, well in this case you can see
a larger opening that allows the sound
and the air to kind of bounce around,
pick up moisture from the air
or create a resonance of your sound.
Opening of the auditory tube.
The auditory tube is what leads to
your internal ear, so that's how you can
help to relieve some pressure in the internal ear.
Pharynx is simply the back of the mouth,
back of the nose.
It's the tube that runs down from the nose
and mouth down to the throat.
Epiglottis I mentioned, it helps prevent
food and liquid from getting down the lungs.
The glottis is simply the opening.
When the epiglottis is opened, it allows
air to pass through the glottis
but when you're swallowing food or liquid
the epiglottis bends down, blocking the glottis
preventing things from going into the lungs.
You know that larynx, it's kind of
that cartilaginous projection.
It's usually more prominent in males than females.
You think of it as the voicebox.
It's just that cartilaginous projection there.
Both males and females do have it, just different sizes
depending on male and female.
And the trachea.
The trachea will take the air and transport it
down your throat, down to the chest
and towards each lung.
Now the lower respiratory tract, we saw
the overview already.
We start with the larynx.
Because the larynx is cartilage-filled,
it helps keep the airway opened.
It makes sure that the air goes into the trachea
but also makes sure that the food and liquid does not.
The larynx helps a little bit with sound production,
considering air is passing through.
It kind of creates a little vibrational bit of sound here.
Trachea.
Simply put, the trachea is meant to be a transport.
It allows the air to get from
your upper respiratory down to your lungs.
Once the trachea stops it branches off
into two tubes, a right and left bronchi.
Those bronchi then keep splitting and splitting
so there's a whole branching network of tubes
that are leading into your lungs, bronchi.
Once they reach the lungs, their purpose, exchanging gas.
Allow oxygen to go into your blood for transport,
allow carbon dioxide to leave your blood
so you can exit it out.
So here's the larynx.
You can see it starts right up on top.
It's nice and cartilaginous, nice and solid.
The trachea leads down into
the right and left bronchus.
Well, from there you can see how it keeps
branching and branching and branching.
Eventually it branches into what are called bronchioles.
Bronchioles are simply smaller tubes.
The tubes keep getting smaller and smaller and smaller
until eventually you reach these clusters of alveoli.
The alveoli clusters are what house
the individual spherical structures of the alveoli.
That's where the gas exchange occurs.
Before we can get down to the trachea and the larynx,
we have to go through this opening
where the vocal chords are.
The vocal chords are simply going to be
fibers that are stretched tightly across the opening.
The left hand, or the a figure here,
you can see how the vocal chords are opened,
while the right hand figure or the b one,
you can see how the vocal chords are closed.
Depending on how close or how far away vocal chords are
they create different sounds.
You then take those different sounds
and you shape them.
You shape them by moving your tongue,
by the shape of your mouth, how much your mouth is
open or closed, do you have a nasal congestion?
All this affects your sound.
So how do you protect it
when you're constantly breathing in all of
these foreign particles?
Well, we already mentioned mucus.
Mucus is meant to entrap.
Mucus is meant to prevent different microorganisms
from getting down to your lungs.
But you're saying well, that mucus picks up a lot of stuff.
Thankfully, you have cilia with the mucus.
The cilia are going to take this mucus
and move the mucus up the respiratory tract
until it can get out of the respiratory tract.
If you have a cold or allergies,
you notice that increased amount of mucus
in the back of your throat.
Well one of the places it's coming from is right here.
But if you're healthy, no allergies,
you probably don't even know that mucus
is coming up and it's simply being dumped down
your esophagus.
It's being dumped down the esophagus
to go down into your stomach.
Your stomach then just destroys it all.
Smoking can damage the cilia.
So if you damage the cilia, now the mucus
is having a hard time being removed,
if it's removed at all.
That's where this whole cough reflex comes in.
A cough reflex is basically your body's way of saying
hey, we've got mucus on these cilia right here.
We want to get rid of the mucus.
So you can see these kind of pinkish little things here.
This is a graft of your inside of your trachea.
The pinkish things are the little cilia
as it helps it to move the mucus along.
If you have a real lot of buildup in here
that cough reflex can trigger and tries to
clear this whole passage out by causing
you to cough and use air to forcibly
expel the mucus.
But now this one over here, you see
the smoker's airway.
Notice anything missing?
Yeah, the cilia are pretty much gone.
There's a few left around but for
the most part they're gone.
A lot of times the chemicals in
someone's cigarette smoke, or for that matter
other types of smoke, are going to
damage the cilia, making the environment
less habitable to that type of cell.
Well, less cilia means more chance of
microorganisms staying in mucus
and staying in your system.
So a healthy system's a whole lot better
because it helps get rid of any
foreign particles, get rid of those microorganisms.