Name: Lub Dub
Uploaded: 2017-10-19T16:48:01.000Z
Duration: 9 min 50 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

If you take a good long
listen to your heart,

you'll actually notice
that it makes sounds.

Adverbs of manner

what that would spell
out like, usually it's

something L- U- B, D- U- B. And
it just repeats over and over

And to sort of figure out
where those sounds come from,

what I did is I took
that diagram of the heart

that we've been using
and actually exaggerated

And we'll use those
valves to kind of talk

through where those
sounds are coming from.

So we've got at the top, blood
is coming into the right atrium

into the left atrium and
then the left ventricle.

So let's start with blood going
from the right atrium this way

Now, at the same moment
that blood is actually

going from the right atrium
to the right ventricle,

blood is actually also
going from the left atrium

Now, you might think,
well, how's that possible?

How can blood be in
two places at one time?

But now remember that
blood is constantly

had some blood that was
coming back from the lungs,

and that's what's dumping
into the left ventricle.

And in a new cycle,
you have a bit of blood

that's going from the right
atrium to the right ventricle.

that are full of blood-- the
right and left ventricle.

Now, to get the blood
into those ventricles,

And specifically, let's
label all the valves now.

And then up here, you
have the pulmonary valve,

and this'll be just a P.
And on the other side,

you've got the mitral valve,
which separates the left atrium

So these are the four
valves of the heart.

And as the blood is
now in the ventricles,

you can see that the tricuspid
and the mitral valve are open.

Now, I've actually drawn the
pulmonary valve as being open.

And the answer is no,
because what happens

is that as blood is moving
down from the right atrium

Black arrows represent the bad
or the wrong direction of flow.

trying to go that way, which is
not the way it should be going.

What happens is that
these two valves, they,

They're going to basically
just jam up like this,

and they're not going to
let the blood pass through.

So this is what happens
as that valve closes down.

Let's imagine you have some
backwards flow of blood

by accident, meaning that it's
going in the wrong direction.

Well, then these valves
are going to close down.

So the white arrows represent
the correct flow of blood,

and the black arrows represent
the incorrect flow of blood.

the aortic and pulmonary
valve, are actually

closed when the mitral and
tricuspid valve are open.

So now our ventricles
are full of blood, right?

And let's say they squeeze down,
and they jettison all the blood

Well, now you're going to
have-- this is actually

These arrows become white,
because the direction of flow

is going to be in the
direction we want it.

And they allow the blood to go
the way that we want it to go,

so now blood is going to flow
through those two valves.

But similar to before, you
could have some backflow here.

Subtitles ListPlay Video

Lub Dub

sort

constantly

assume

rhythm