Incredible Human Machine (3/9)

[MUSIC PLAYING]

[CHEERING]

Few of us think about the trauma
we generate in our voice boxes

when we talk, sing,
laugh, or scream.

[CHEERING]

But take a look down
the talented gullet

of Steven Tyler,
Aerosmith's lead singer--

[SINGING]

--and you get a feel for why
he, and millions of others,

are wreaking havoc on
a delicate instrument.

OK.

[INAUDIBLE]

Tonight, as Aerosmith
performs, Dr. Stephens Zeitels

and his team from
Massachusetts General Hospital,

will get a rare treat.

Yeah.

With the help of special
monitoring equipment,

they'll see how this
famous pair of vocal cords

holds up to such extremes.

Doctors Zeitels, one time
for my kids, what do you--

what do you-- what
is this monitoring?

What we're going to be doing
is looking at the vibrations

on the skin of your neck,
which is going to pick up

the intensity of your voice.

Mm hm.

It's going to be picking up
the loudness of your voice.

Mm hm.

Thank you, doctor.

Thank you.

Into the abyss.

[THROAT CLEARING]

Oh.

Into the great beyond
with doctor Zeitels.

And that one--

Backstage, throughout
tonight's concert,

Zeitels will use an endoscope
to examine Tyler's voice

box up close.

[INAUDIBLE]

Try not to touch the sides.

Yup.

[THROAT CLEARING]

That's great, Steven.

Put your tongue out for me.

Just breathe.

Say hee.

Heee--

It's a rare insight into what
goes on in a high performance

singer.

Mm.

Eh.

Real-time measures
of a performer,

who is at the top of his
game doing a live performance

for thousands of people.

It's a first.

It hasn't been done before.

[SINGING]

To produce these
kinds of sounds,

Tyler's vocal chords are
slamming together an average

of 170 times a second.

Ah.

That's more than
half a million times

during the course of a concert.

Ah.

And nearly a billion
times during the course

of his 30-year
professional career.

There's no part of
the human body that

likely sees these kinds of
collision forces and shearing

stresses, which is why vocal
folds essentially wear out

over time.

It's also why, just months
earlier, damaged vocal chords

canceled much of
Aerosmith's tour.

Tyler could barely sing--

[SINGING]

Just breathe.

--forcing him to
undergo Zeitels' knife.

Or laser, in this case.

Stephen basically had
a vocal bleed, which

is very common in performers.

Common, in fact, to many
with the gift of gab.

From attorneys to telemarketers.

The laser surgery, which
Zeitels and his team pioneered,

works by sealing off damaged
vessels to stop the bleeding.

These aren't some Photoshop
tricks you're looking at.

This is Steven
Tyler's voice box.

And these are his fragile
blood vessels disappearing.

He was able to zap
those blood vessels.

So I go out there and just
sing and hope for the best.

[MUSIC - AEROSMITH, "DREAM ON"]

Now, as Stephen heads on stage,
his finely tuned vocal chords

spring into action.

And we get a front row seat.

This is Steven Tyler outside--

Anytime that I look
in the mirror--

--and in.

Anytime that I
look in the mirror.

All these lines on my
face getting clearer--

Every time we
exhale, we force air

through our two
membranous vocal chords.

When we bring them
together they vibrate.

Dream on.

Dream on.

These vibrations produce sound,
much like a guitar string

after it's been plucked.

Dream on.

Muscles open and
close the chords,

and change the sound's pitch.

Dream until your
dreams come true.

During low notes, the chords are
loose and vibrate more slowly.

Dream on.

Dream on.

Dream on.

But for those falsettos--

Dream on.

--his chords stretched
to the limit--

Dream on.

--and vibrate, virtually,
off the charts.

A surprisingly simple feat
for Tyler's pliable chords.

I mean to go from, and
woke up this morning

on the wrong side of the bed.

And all them things you
said, and all the things I

said, but-- and
it's in that voice.

And then, you know,
of course, and I

don't want to miss a
thing, is in that voice,

and then Dream On is Dream on.

Dream on.

And they've asked
me before, how do

you sing that song every night?

Well that's one of the
easiest ones for me to sing.

[SINGING]

As for what translates these
vocal vibrations into song,

that happens much farther
up in the throat, the mouth,

the tongue, the nose.

These are what put the
stamp on a human sound,

distinguishing the likes
of Steven Tyler from just

about anyone else.

[MUSIC - AEROSMITH, "LOVE IN AN
ELEVATOR"]

Bettin' on the dice--

After some two hours
of vocal gymnastics,

initial data reveal
that Tyler's chords

crash together more than
half a million times--

I really need a
girl like an open--

--and covered the equivalent
of more than six miles.

[CHEERING]

And there's no
indication they'll

be wearing out anytime soon.

[CHEERING]

Thank you!

[CHEERING]

Dramatic as it may be,
singing is a side effect

of a much more crucial process.

The real reason why air
passes through our mouths

is breathing.

[CAR HONKING]

[BREATHING]

We wouldn't survive much more
than a couple of minutes if we

didn't.

[BREATHING]

With every inhale,
our noses or mouths

suck in about a pint of air
some 20,000 times a day.

We can follow it on its
journey down the throat, passed

the voice box, and into
the windpipe, or trachea.

As it approaches the
lungs, air has a choice.

Left or right?

But both lungs lead
to the same end.

The lungs' bronchi
divide and divide

into thousands of smaller and
smaller branches, progressively

filtering chemicals, dust,
and smoke in the air,

until, finally, they come to
an end in this pouch-like ball

called, an alveolus.

[MUSIC PLAYING]

More than 300 million of
them spread across each lung

with a combined surface area
roughly a third the size

of a tennis court.

In less than a second,
oxygen molecules

exit the lungs here through
walls just one cell thick.

They'll then cross into
a surging bloodstream,

be whisked throughout the body,
and provide precious resources

to every one of our
trillions of cells.

Assuming air gets to this point.

The blue, here, shows how a
healthy lung empties oxygen

into the bloodstream.

In this smokers lung, oxygen
can't empty nearly as well.

Then there's the exhale.

Carbon dioxide, the waste
product of breathing,

makes the opposite
journey back out.

Another inhale and our
breathing apparatus

offers yet another gift with
delightful or disgusting

results.

With every new
breath, our noses can

distinguish as many as
10,000 different odors.

Some pleasing, some not.

They can calm, caution,
or make our mouths water,

but the essence of
any aroma, from a day

at the beach to fresh baked
bread, is pure chemistry.

Isobutyl acetate, vanillic
acid, and more than 300

different chemicals,
for example,

come together to give chocolate
its unmistakable bouquet.

A rose, by any other name,
might be phenol ethyl alcohol.

And once fish is
passed its prime,

it owes its stench
to trymethylamine,

a byproduct of the
bacteria growing inside it.

Whatever the chemical,
deep inside our noses,

there is a small patch of
about 10 million cells waiting

to sniff it out.

These cells carry about
1,000 different kinds

of receptors on their surfaces.

When the right odor
chemical meets up

with the right receptor,
an electrical signal

gets sent to the brain.

And finally, the
incredible machine, smells.

All in all, our
respiratory systems

are ingenious multi-taskers,
sorting thousands of smells

at each intake.

Capable of making thousands
of sounds on the way out.

But no matter how
pleasant the by product,

there is a higher
calling to breathing.

Every breath we
take delivers oxygen

to our trillions of
power hungry cells

and gets our hearts to pump.

[HEART BEAT]