00:01
3. The changes in the bronchial
tubes and the alveoli.
00:06
Now, you might be wondering
what that blob is up there?
Well, it's actually this.
00:10
Gum.
00:11
Yeah.
00:12
Now, we want to use
this as another analogy
for you to understand kind
of how the airways work.
00:17
But think about when
you're chewing gum,
not when you just took it all the package,
and the stick is still kind of tough.
00:23
But after you've chewed
it up a little while,
think about the
characteristics of gum.
00:29
Right, so I can change it.
00:31
Right?
It's elastic, I can stretch it.
00:36
Now, if I took it out of my
mouth, which I'm not going to do,
because my mother
would be so proud.
00:42
I could stretch it and there
would be no problem, right?
But if I took that gum out of my mouth
and I set it on a counter overnight,
which would make me the
worst roommate ever.
00:54
But if I took it on my mouth and
I set it on the counter overnight,
I got up the next morning,
what difference would
you see in that gum?
Could I pull it in shape
it like I could before?
Not likely.
01:07
Because it lost its elasticity.
01:09
It's stiffer now so it's
not as easy to stretch it.
01:13
Now, our lungs are not made of
gum, it's the same concept.
01:19
We need airways to keep their
shape but yet be elastic, right?
Be able to move and change.
01:25
This is the same thing that happens
in our airways when they become stiff,
they no longer function as well.
01:31
So this happens in the functional
components of our respiratory system,
both the bronchial
tubes and the alveoli.
01:38
When we say they become stiffer,
this is what we want
you to think about.
01:42
Instead of being able to
fill with air and expand,
they don't move as much
they lost their shape,
and their ability to be
elastic or to change.
01:52
Now, the bronchial tubes increase in size
as they become stretched and weakened.
01:56
So kind of stiff and big and so
they're kind of over and enlarged.
02:00
Think of like a
piece of elastic.
02:02
You know, if I took an elastic band and
I stretched it and over stretched it,
it isn't as useful when it's
all stretched out, right?
We need it to be able to move.
02:12
When those airways become
overstretched and weakened,
they can't contract again.
02:19
Now this can start to
happen as early as age 40
which again why is exercise and movement
and being active is so important.
02:29
Now, let's break it down
even more about the alveoli.
02:33
Look at our picture
of an alveoli there.
02:35
We're going to talk about the
changes that happen on that level.
02:38
You know that the alveolar wall
is usually one cell thick, right?
So is the capillary wall,
they're both super thin like that,
so that gas can pass between
them the CO2 and the O2 exchange.
02:50
In this case, your airway walls, the
alveolar walls begin to become thickened.
02:57
Now also you have less
surfactant available.
03:00
This is going to make the
alveoli less effective
because what you need for good
gas exchange is an intact alveoli
with plenty of surfactant to
help keep that alveoli open.
03:13
So the alveoli become flatter,
they lose their shape and
they lose their elasticity.
03:18
Now, aging alveoli have less
surface area for gas exchange.
03:23
Why?
Because remember what
we just talked about,
you have less surfactant, those walls
become thicker, they become flatter,
therefore you have less
surface area for gas exchange.
03:34
So overall, as we age the breathing
process becomes less efficient.
03:38
We have lost those elastic
fibers in the airways.
03:41
And so I might even have alveoli that
collapse and trap air in my lungs.
03:46
So I have less
alveolar surface area,
I have less vascularization,
less surfactant,
and therefore I have
less gas exchange
or a decrease in the
efficiency of the gas exchange.
04:00
So all these changes end up in less
oxygen may make it into the bloodstream.
04:06
So now what's the difference
between Jose and Enrique here?
Well, it's simple.
04:11
Think of Jose as the gum that we
never stopped chewing or playing with.
04:16
We stretch it, we get it back to its
original shape over and over again.
04:19
Now it will stiffen with time.
04:22
But since we're
constantly using it,
it's going to take longer for it
to lose its elasticity completely.
04:28
But how does Jose do this?
How does he achieve
this in real life?
Well, the answer is simple.
04:34
It's activity and exercising.
04:36
Since Jose has been a
runner all of his life.
04:39
He hasn't stopped stretching
his alveoli in his lungs,
and so they haven't become
as stiff as Enrique's.