There is nothing more familiar or more mysterious...
more breathtaking in its action...
marvellous in its mechanics...
exquisite in its range of senses...
and staggering in its ability to understand.
On a fantastic voyage through a single day,
we plunge deep into the routine miracles of the human body.
Dream on, dream on...
Our instruments,
engines,
infrastructure,
roadways and circuitry.
Through 1 0,000 blinks,
20,000 breaths,
1 00,000 beats...
Hello.
..today is an ordinary, extraordinary day
in the life of the incredible human machine.
Bits of stardust is really all we are.
Oxygen, carbon, hydrogen
and a handful of elements that would cost very little at any chemical supply shop.
But get these chemicals together,
marinate in a hospitable place for about 3.8 billion years
and the mundane mix of molecules becomes precious.
There are more than six billion human bodies living on Earth
and each of us is the amalgamation of some 1 00 trillion microscopic cells.
While the blueprint for each individual are 99.9 per cent identical,
no two of us are exactly the same.
As a new day dawns,
each human machine begins the succession of miracles
that will take it from morning to midnight.
Cells, senses,
muscles, bones,
hearts, brains,
all must marshal their forces and unite just to wake us up.
(Alarm beeps)
(Sighs)
At the surface of it all,
a velvety overcoat of cells and protein keeps us in
and the rest of the world out.
lt's our armour,
our radiator,
our entree to pain and pleasure.
lt is the body's largest organ -
our skin.
Smooth and silky to the eyes and touch
a closer look presents a very different landscape.
Magnified 600 times, our outermost skin is nothing but dead cells,
riddled with ridges and grooves
and pocked with countless bumps and holes.
Look closer still and we find hundreds of thousands of bacteria
inhabit every square inch of us.
With every tick of the clock, our dead skin gets sloughed off.
We shed at least 600,000 particles of skin an hour-
about a pound-and-a-half's-worth each year,
which accounts for as much as 80 per cent of the dust in our houses.
But there's plenty of skin to go around.
lf we could peel it off and lay it out flat,
the average person's skin would cover some 1 8 square feet.
Though just millimetres thick,
it would weigh about 6lb.
And we're constantly making more.
Just wait a month or so and you'll have a shiny new coat.
Which means skin can't be all dead.
Dip below the surface and you find cells continuously dividing
to replace those dead cells above.
Kilometres of blood vessels pulse to skin's connective tissues.
Not forgetting all those precious nerve endings.
45 miles-worth of nerves stretch from our heads down to our toes,
and many reach to our skin.
Some parts more than others.
lf sensitivity were size-dependent, we would look something like this.
Our supersensitive hands, feet, tongue and lips,
each packed with touch receptors, would swell enormously.
Our legs, on the other hand, would resemble a chicken's.
Good thing for us there is more to this organ than touch.
Skin is also our heating and cooling system.
And by helping maintain that comfy 98.6 degrees Fahrenheit
it keeps us alive.
Through its network of blood vessels,
skin carries as much as one-third of the heart's hot, freshly-pumped blood.
Get too hot and these vessels can widen to release heat from our bodies.
But sometimes that's not enough.
A good workout can raise the body's temperature several degrees above normal -
a potentially deadly state if it weren't for skin's slick safety net..
sweat.
More than two million holes across our skin
can produce up to half a gallon of the liquid in an hour.
The heated droplets evaporate into the air, and leave the body cool.
Through a special camera that images heat, not light,
we can see this air-conditioning system at work.
The hotter the body, the deeper the red.
No surprise, some of the warmest parts of our bodies -
our foreheads, palms, and armpits -
correlate with the greatest concentration of sweat glands.
But we're more likely to encounter the opposite extreme in our morning routine.
Exposed to a chill, tiny musclesjerk our hairs to attention,
bulging the skin around them.
We call them goose bumps.
Scientists have dubbed us ''the naked ape''.
But look closely
and we find we're anything but naked.
Some of our skin cells form tubes that produce hair.
And we have as many of these follicles punctuating our skin
as do our hairy relatives.
Some five million of them.
As the new hair cells divide,
they push old ones up and out.
By the time our hair breaches the surface, it's dead.
Which is why we don't feel pain with every haircut.
Cleaned and groomed, we venture into the bustling morning world.
Around us, other incredible human machines greet the day,
in all different sizes and shapes,
colours and textures.
But on some level, we all inhabit the same skin.
Below the surface, each of us has about the same number of melanocytes,
the cells that pump the dark pigment melanin into our hair and skin
and give them colour.
lt'sjust the amount of melanin these cells produce
that determines whether we are black or white, brunette or blonde.
Generally speaking, the more melanin, the darker.
That same chemical adds colour to a very different sensory organ.
Blue or brown,
green or hazel,
they are the most vital sensory organ that the incredible machine has.
Our day hasjust begun,
and the magnificent miracle of sight leads the way.
Navigating the morning rush hour is something most human machines do on autopilot,
oblivious to the staggering task we leave to two gelatinous orbs.
Eyes sit squarely on the front of our faces for a reason.
Peering forward, and set apartjust enough to let us gauge distance,
they let us spot and track whatever we desire.
ln microseconds, our eyes sight, follow,
focus and process images fractions of an inch long
or moving at hundreds of miles per hour
enabling us to assess and appreciate the world around us more than any other sense.
They may be the windows to our souls,
but on a less poetic level, eyes are just hungry harvesters of light,
trapping and translating it into electrical impulses the brain can understand.
Light hits the cornea first.
This transparent layer, cleansed and lubricated about 1 0 times a minute with every blink,
admits and directs incoming light rays.
From there, they pass through the dark opening of the pupil,
then a transparent protein lens.
Gatekeepers of light, the muscles of the colourful iris squeeze the pupil closed
against too much light.
Not enough, the iris relaxes and the pupil opens.
And in just a fraction of a second, it can slide back and forth between the two.
Focused by cornea and lens,
light then flies through the jelly-like bulk of the eye and onto its rear wall.
Just about a hundredth of an inch thick, this is the retina,
where more than 1 20 million photoreceptors convert light into electrical impulses,
before processing and shipping them off to the brain.
ln a mind-boggling feat that soaks up about a third of our brain power,
our brains continually compare new data with information processed a split second before.
Combine that with what they already expect to be there
and vision is born.
At least, that's how it's supposed to work.
When it doesn't, the world can look more like this.
62-year-old Linda Morfoot has a genetic disease called retinitis pigmentosa.
which has been gradually degrading her eyes'photoreceptors for the past 40 years.
They haven't turned light into sight for the last ten.
lt's frustrating to lose your sight
because you run into things, you run into people.
And it can be depressing.
Just open up real wide.
Very good.
Now, thanks to Dr Mark Humayun of the University of Southern California,
she may see again.
All along we've been told it's impossible, it's science fiction, it can't happen.
Look up.
Humayun has implanted an ingenious little device at the back of Linda's eye.
Just 1 6 electrodes that should act as a simple retina,
turning light into impulses that can be sent to the brain.
We lay it right on the retina
and the current stimulates the underlying nerve cells.
When this information is received by the brain, you see a spot of light.
To perceive those spots, Linda had to first wear a special pair of sunglasses that capture light,
convert it into electrical signals,
and fire up the implants in her eyes.
As the doctors activated the electrodes one by one,
it started to work.
lt was crude, but Linda could now see light and movement.
As they turned more and more electrodes on,
l could see the lights on or the doorway.
l could tell the difference between black and white.
lt was exciting. Yes, it was.
1 6 signals hardly compares to the million or so a working retina transmits.
But with each passing day, her brain compensates,
and Linda sees more detail.
We thought that 1 6 electrodes would never ever give Linda or any other patients
the level of vision they have been able to attain.
The brain fills in the missing gaps.
From simple flashes of light
our brains can somehow conjure meaningful images.
So, now, after 1 0 years of blindness,
Linda can see the grandchildren she never saw before.
They like to run in front of me. ''Where am l, Grandma? Where am l?''
l'm more connected to them,
a little more part of their lives, you know.
Even for those of us lucky enough to see 20/20
the sense of sight does not work alone in the incredible human machine.
On either side of our heads are the body's microphones - ears.
But ears do much more than hear.
They give us balance, telling us where we are in space at any given moment.
Riding a bike, landing,
perfecting a dive,
even taking a baby step,
all would be impossible without the intricate gadgetry deep inside our ears.
Here, three fluid-filled tubes work like carpenters'levels to help keep us balanced.
When we turn our heads, the fluids move, stimulating nerve cells,
and orienting the brain in three dimensions.
Up-down, left-right,
forward-backward.
lt's a powerful little mechanism that we can stimulate artificially.
Welcome to the weird world of tomorrow.
With a special electrified headset,
scientists in Japan have taken hold of our balancing centres.
By sending current down to those nerves in our inner ears
they've created remote-controlled human beings.
TRANSLATOR: l've never experienced such a sensation.
lt was like being drunk on the deck of a boat rocking in the waves.
The current is low voltage,
just enough to throw people off balance and compel them to walk left, right,
even trace the shape of a giant pretzel.
TRANSLATOR: My body was out of control.
lt was swaying to the left and to the right.
We can even remote control ourselves.
We're not trying to control people
or manipulate their actions.
Rather, we want to help them,
help guide them.
Especially people with balance problems or dizziness.
The researchers say one day it may even help navigational devices, like GPS,
to physically guide us to our destinations,
or make a video game feel more like a rollercoaster.
Our ears provide another powerful sensation to enrich our day.
Every time we, or anything else for that matter,
make a move or vibrate, we create ripples in the air.
Distinct waves all travelling at different frequencies,
which waft into our ears at some 750mph
and produce sound.
Like radar dishes, our ears channel the sound waves deep into our skulls.
Our eardrums vibrate in tune to the frequencies,
moving three tiny bones, each about as long as a grain of rice.
Magnified 20 times we can see the ear hear,
inside...
..and out.
Love in an elevator
Livin' it up when l'm going down
Love in an elevator
Turnin' it up till l'm upside down...
The bones'movements get converted to pulses of pressure
which vibrates fluid
which disturbs tiny hairs
which excite nerve cells
which translate all of this to the brain.
One sound perhaps more than any other is music to our ears -
the human voice.
lt's an astonishingly versatile instrument, but it's vulnerable.
As lead singer for Aerosmith,
Steven Tyler's work depends on his vocal cords.
l need a girl like an open book
To read between the lines
Few of us think about the trauma we generate in our voice boxes when we talk, sing, laugh
or scream.
But if you were to look down the gullet of Steven Tyler,
it would show why he, and millions of others,
are wreaking havoc on a delicate instrument.
Thank you!
Tonight, as Aerosmith perform,
Dr Steven Zeitels and his team from Massachusetts General Hospital
will get a rare treat.
With the help of special monitoring equipment
they'll see how this famous pair of vocal cords holds up to such extremes.
Dr Zeitels, one time for my kids, 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,
it's going to be picking up the loudness of your voice.
Thank you, Doctor.
lnto the abyss.
lnto the great beyond with Dr Zeitels.
Backstage throughout tonight's concert,
Zeitels will use an endoscope to examine Tyler's voice box up close.
Try not to touch the sides.
Stick your tongue out for me.
Just breathe. Say ''Ah''.
Ahhh!
lt's a rare insight into what goes on in a high-performance singer.
Real time measures of a performer
who is at the top of his game
doing a live performance in front of thousands of people -
that's a first, hasn't been done before.
(Sings high note)
(Laughs)
To produce these kinds of sounds,
Tyler's vocal cords are slamming together an average of 1 70 times a second.
That's more than half a million times during the course of a concert
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.
lt's also why just months earlier damaged vocal cords cancelled much of Aerosmith's tour.
Tyler could barely sing...
(Sings high note)
Just breathe.
..forcing him to undergo Zeitels'knife,
or laser, in this case.
Steven 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.
This is Steven Tyler's voice box
and these are his fragile blood vessels disappearing.
He was able to just zap those blood vessels
so l go out there and sing and hope for the best.
Now, as Steven heads on stage, his finely tuned vocal cords spring into action.
(Guitar intro)
This is Steven Tyler outside...
Every time that l look in the mirror
- ..and in. - Every time that l look in the mirror
All these lines on my face getting clearer
Every time we exhale,
we force air through our two membranous vocal cords.
When we bring them together, they vibrate.
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.
During low notes, the chords are loose and vibrate more slowly.
Dream on, dream on, dream on...
But for those falsettos...
(High-pitched) Dream on, dream on
His chords stretch to the limit
and vibrate virtually off the charts.
(Holds high note)
A surprisingly simple feat for Tyler's pliable chords.
l mean, to go from,
(Gruffly) ''l woke up this morning on the wrong side of the bed
And how l got to thinking And all them things l said''
but it's in that voice.
And then, you know, of course... (Higher) ''And l don't want to miss a thing''
is in that voice.
And then Dream On is: (Falsetto) ''Dream on, dream on''
and they've asked me before, ''How do you sing that song every night?''
That's one of the easiest ones for me to sing.
Go.
(Rising pitch)
As for what translates these vocal vibrations into song
that happens much further up
in the throat, the mouth, the tongue, and the nose.
These are what put the stamp on human sound,
distinguishing the likes of Steven Tyler from just about anyone else.
After some two hours of vocal gymnastics,
initial data reveal that Tyler's chords crashed together more than half a million times,
and covered the equivalent of more than six miles.
To read between the lines
(Wild cheering)
And there's no indication they'll be wearing out anytime soon.
Thank you!
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.
We wouldn't survive much more than a couple of minutes if we didn't.
With every inhalation our noses or mouths suck in about a pint of air
some 20,000 times a day.
We can follow it on itsjourney down the throat
past 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.
More than 300 million of them spread across each lung
with a combined surface area roughly a third the size of a tennis court.
ln less than a second, oxygen molecules exit the lungs here
through wallsjust 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.
ln this smoker's lung, oxygen can't empty nearly as well.
Then there's the exhalation.
Carbon dioxide.
The waste product of breathing makes the opposite journey back out.
Another inhalation and our breathing apparatus offers yet another gift,
with delightful or disgusting results.
With every new breath, our noses can distinguish as many as 1 0,000 different odours.
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.
lsobutyl 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 phenyl ethyl alcohol.
And once fish is past its prime,
it owes its stench to trimethylamine,
a by-product of the bacteria growing inside it.
Whatever the chemical
deep inside our noses, there is a small patch of about 1 0 million cells
waiting to sniff it out.
These cells carry about a thousand different kinds of receptors on their surfaces.
When the right odour 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.
(Laughter)
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.
(Heartbeats)
Every second of every day,
every cell in our body needs oxygen to power its activities and survive.
More than a gallon of blood needs to travel through some 60,000 miles-worth of arteries,
veins and capillaries.
And one little 1 0-ounce heart has the Herculean task of driving the whole system.
lt begins with a heartbeat
which sends fresh, oxygenated blood from the lungs streaming into the heart.
lf you stored up the power from all the heartbeats in a day,
it could lift a car some 30 feet into the air.
The heart is a muscular pump to its core.
Even if it's removed, it can still function all on its own.
lts genius lies in its cardiac cells -
millions of them all beating in tune.
But heart cells don't necessarily have to be born in the heart.
These are stem cells coaxed into beating by Dr Amit Patel
and his colleagues from the University of Pittsburgh Medical Center.
Those cells had nothing to do with becoming heart muscle.
But within less than a week,
we were able to train them to become heart muscle.
Stem cells live in many tissues in our bodies,
standing by for maintenance and repair.
Unlike our other cells, stem cells can develop into just about any kind of cell -
brain, muscle, bone, fat.
Almost anything you could possibly think of in the body,
over 220 different cell types,
all come from stem cells.
49-year-old Michael Carlat desperately hopes that stem cells can turn into heart cells
in his own body.
A few years ago, his heart started to give out.
Catastrophically.
Mr Carlat's heart is very sick.
He had a very large heart attack.
When you look at the heart, it's a pump.
Normally, 60% of what goes into the heart should come out with every heartbeat.
ln Mr Carlat, only 30% comes out.
l was put on this heart transplant list
and waited over a year for something to happen.
There's 4,500 people on the list.
l'm 275lb. l'm 6'4''.
lt's hard to find a match for me.
Waiting on that list would have been waiting to play out the last couple of years and that'll be it.
With few other options,
Michael enrolled in a highly-experimental clinical trial,
in which Patel performs a risky bypass on his heart's damaged area,
extracts stem cells from his hip bone,
and injects them back into Michael's heart.
lt's not clear what these cells will do there.
Help grow new blood vessels?
lncrease the number of muscle fibres?
The hope is that they'll help coax Michael's heart into healing itself.
We don't know what they do, but they seem to know what's required.
And though it's early, in Michael's case they already seem to be working.
Just three months after his surgery,
Michael's heart pumps 25% more blood than it did before.
The difference between barely climbing a flight of stairs
and playing basketball.
lt's working, so l'm not going to ask why, how, what.
He saved my life. lf l didn't go to him, l probably would have just...
..not been around today.
Of course, it takes more than just a good pump to give life-giving liquids around the body.
lt takes good plumbing.
Once out of the heart,
blood carries our vital oxygen supply through smaller and smaller arteries,
eventually reaching an even narrower network of capillaries.
These tubes are so thin that red blood cells thousandths of an inch across,
must squeeze through single file.
Ten billion capillaries fan throughout the body
so that our organs and tissues are never far from a fresh supply of oxygen.
Carbon dioxide and other toxins need to get out
and veins are crucial drainpipes carrying the blood back to the heart,
then to the lungs for cleaning.
Blood travels through more than 60,000 miles of vessels -
more than twice around the Earth.
lt circulates all around the body in less than a minute,
every minute of our lives.
And sometimes blood moves even faster.
The more oxygen our cells burn,
the harder our heart and blood vessels have to work to deliver more.
When we eat, it rushes to our stomachs.
When we run, to our muscles.
Even when we read, more oxygen must get to our brains.
As efficient as this blood delivery system is, though,
it has its limits.
Limits experienced by pilots in the US Navy.
These are the Blue Angels,
the US Navy's elite flight exhibition team.
Experiencing up to 9Gs at times - nine times the force of gravity -
these pilots routinely push their bodies to extremes.
Well, 9Gs to me squashes me in the seat pretty hard.
l weigh about 1 80lb, so it's nine times that.
l'm not going to do the math for you right now
but it squashes me pretty hard.
Some 1,600lb of pressure on solo pilot Ted Steelman
is enough to push the precious oxygen-carrying blood right out of his brain.
Same thing as if somebody strangles you or anything like that.
You're going to lose blood to your brain and you're going to pass out.
To counteract this fighter pilots typically wear gravity or G suits,
which automatically inflate to squeeze blood where it's needed.
Flying a mere foot-and-a-half apart,
the Blue Angels can't chance it.
The slightest jolt from a G suit on the stick could be disastrous.
When you're talking about stick inputs of as much as a sixteenth of an inch,
when you're doing 400mph a mere 1 8 inches from the guy next to you,
it actually has huge ramifications.
So, no movement of the stick unless intended is what you're looking for.
Which means that these pilots must use their muscle
to force blood up to their brains.
What l do is what we call a hick manoeuvre.
lt's a culmination of breathing technique
in that you contract the chest with a ''hick-k''
to keep the overall pressure within the chest cavity high
in about 3-4 second intervals
as well as isometric contractions from the waist down.
By simply breathing and contracting muscles
the body can be trained to withstand extreme forces.
To do it, pilots must face this - the centrifuge.
Like an extreme amusement park ride that spins blood from brains to toes
and tests how long a pilot is able to resist.
They train their bodies, like a marathoner will train their body
to go out and run 26 miles at five-minute miles.
These guys train their bodies to respond to the Gs.
Legs and glutes, keep them in.
But even highly-trained specialists like Steelman can only defy physics for so long.
lt happened right at the very end of the run.
l expected a G release, so what did l do? l relaxed my body.
The moment you relax, the absolute moment you relax,
every single time you're going to pass out under G like that.
Now, when Steelman takes to the skies,
he knows the warning signs and takes evasive action.
Passengers, on the other hand, are a different story.
You'll hear them executing the hick manoeuvre, working hard,
and suddenly it gets quiet, and you look back in the mirror and they just do this.
Their heads are down to their chest.
Fortunately, the effects are only temporary.
Whoa! Did we do it?
Blood is something our brains, and the rest of our organs for that matter,
never want to be without.
But there's more to this liquid than oxygen.
ln a single drop of blood,
up to 400,000 infection-fighting white blood cells are constantly patrolling
and seeking out foreign agents, like viruses and bacteria,
and internal threats like cancer,
and attacking them.
Unfortunately, they don't always win.
And when that happens,
aggressors like these rogue melanoma cells can grow out of control.
Whether our cells work with us or against us,
one thing is certain -
we are tirelessly working for them.
Since we woke up, our heart has beaten more than 20,000 times,
bringing vital oxygen to a hundred billion microscopic masters.
But it takes more than air to feed the machine.
lt takes fuel.
Every time we swallow a morsel of food,
we set it on a journey designed to suck everything useful out of it.
Sit down to lunch, and in the 30 or so hours and 20-plus feet it takes to digest it,
we convert plants or animals into energy
and absorb their chemical building blocks into our own flesh and blood.
Carbohydrates, proteins, fats, vitamins, and minerals -
all of our nutrients come from what we eat.
Digestion actually starts before food crosses our lips.
Just the idea of food can get our mouths to water.
We salivate roughly a pint every day.
And in that saliva are enzymes that, along with our teeth,
begin to break down the food that we eat.
But not before we get to savour it first.
Some 1 0,000 taste buds line our tongues,
each one home to about 50 taste receptor cells that tell the brain what we're eating.
And if some of those precious receptors are scorched off,
it will only take a week to 1 0 days to grow back a brand-new set.
Once the muscular tongue manoeuvres food into our oesophagus, we're on autopilot.
When we eat, a flap of skin called the epiglottis seals off our windpipes.
Except when it doesn't.
l'm OK.
Then it's back to the beginning.
A typical journey down the oesophagus takes about five seconds.
From here it's squeezed, like toothpaste.
Once it passes into the stomach as it's doing here it's time to slow down a bit and digest.
Normally this stretchy, J-shaped bag isn't much bigger than a fist.
(Groan)
But after a big meal, it can expand to more than 20 times that size.
For the next several hours highly acidic gastric juices spew from the stomach's walls,
breaking down proteins in our food while muscle contractions knead and churn it into a pulp.
The acid here is so strong the stomach must continuously secrete a layer of protective mucus
so that it doesn't digest itself.
lt absorbs very few nutrients, though.
For that we pass into the 20-foot ''dis-assembly'' line of the small intestine
with the help of a specialised camera pill.
For about five hours, food's building blocks are pushed, prodded,
sprayed with digestive juices and wrung like a rag here,
until its vital elements are forced through the intestinal wall
and into the bloodstream.
From here, most of our meal's nutrients will flow directly to the liver,
the body's largest internal organ.
The liver breaks down, repackages and delivers nutrients to our cells for growth and power.
Our bodies ultimately try to balance energy intake.
But sometimes more goes in than out.
The result.. fat.
This is how fat looks on the inside... and on the outside.
lt doesn't take a lot of excess calories to make you gain weight.
Just 1 5 more a day than you need - about the amount in four pistachio nuts -
will add a pound and a half of fat over a year.
Once the small intestine has taken in everything worth ingesting,
the rest is pushed along to the large intestine.
For another 20 hours or so, the last of the water is absorbed,
and billions of bacteria work to break down the remaining contents.
ln the end, anything we can't digest gets flushed...
(Toilet flushing)
..out of our bodies.
Food's complicated journey has a larger purpose.
Once we've extracted what we need to feed the incredible machine
and gotten our cellular engines humming,
it's nothing short of astounding what we can do with them,
thanks to amazing contraptions called muscle.
The incredible human machine in action.
Just about every body part, from our skin receptors
to the balance centre in our inner ears,
help to make these amazing complexities of movement seem almost effortless,
automatic even.
But if we peer beneath our skin,
we see that one tissue above all propels us into a thousand different positions.
From the soles of our feet to the tips of our fingers some 650 muscles,
about 40% of our body mass, power every move we make.
As our day pushes on,
these skeletal muscles lift us through it usually without our thinking about it.
Without them we couldn't run or blink, smile or speak for that matter.
Hello?
Just muttering a single word...
Hello?
(Prolonged) Hello?
..involves muscles in the face, lips, tongue, jaw, larynx - as many as 1 00 muscles.
Many of the same muscles let us form a frown.
Turn them upside down and all 34 muscles in the face let us deliver a kiss.
Walking,. a highly coordinated series of falls
that we've taken for granted since we were toddlers
requires no fewer than 200 skeletal muscles.
Back muscles to keep you from falling forward,
abdominal muscles to keep you from falling back.
lt takes 40 or so musclesjust to raise one leg and move it forward.
Now, add into that running,
swimming,
shooting, riding,
and fencing,
and you get an idea of how many different muscles are at work inside Eli Bremer,
top-seeded US Olympic pentathlete.
l think what l do is very normal and someone will ask what a typical training day is.
And l'll tell them, ''Swim about four miles and run about ten miles.''
You know, it's not that big of a deal.
l mean, l think anybody could do it.
And then l get this weird look like, ''You must be crazy.''
So, what propels him?
lf we zoom in on one of these muscles in motion
and closer still at the hundreds of muscle fibres that run its length,
we find two proteins, actin and myosin.
And their actions couldn't be simpler.
They link up, squeezing together like cogs on a wheel.
And then they relax, releasing their grip and going back to normal.
lf during a fencing bout Eli wants to strike an opponent
the actin and myosin in his tricep bind,
while in his biceps they release.
When he winds up for another blow the opposite happens.
Now his biceps bind and his triceps release.
By binding and releasing all our skeletal muscles
we get our every motion.
And 3, 2, 1 ...go!
The more we work our muscles the more actin and myosin we make,
the bulkier our skeletal muscles become,
as Olympic hopeful Doreen Fullhart demonstrates.
To lift, her brain sends electrical impulses down nerves to muscle fibres
telling the actin and myosin to bind...
..and release.
But for our muscles to work, that signal from the brain must get through.
That requires an intricate but delicate wiring system.
(Monitor beeps)
- Have you met Dr Redett? - Good to see you again.
Good to see you.
34-year-old Jason Keck severed some nerves in a logging accident three months ago
and he hasn't moved his left arm since.
Just a few years ago, doctors could do virtually nothing to fix this kind of damage.
Today Doctor Dr Allan Belzberg and his team at Johns Hopkins School of Medicine
will try to get Jason's wiring system working again.
The nerve is just an electric cable, when all is said and done.
A very sophisticated one, but nonetheless an electrical cable.
We have a nerve that's been broken, that's been stretched and snapped.
We can bring the ends together and fix it.
lf we can't get the ends together we can fill the gap in and splice in some material.
And if we can't do that then again we go to this nerve transfer concept
of robbing Peter to pay Paul.
Anything? Nothing?
Paul in this case is Jason's arm.
To find a suitable Peter to rob, Belzberg zaps various nerves with electricity
to see where current is being lost.
Not unlike an electrician checking wires in a house.
What makes this interesting is everybody's wired just a little bit differently.
The hope is that at least some wires are still plugged in.
Sadly, Belzberg discovers this isn't the case with Jason.
Just terrible.
Unfortunately, all five of the major nerves that leave the spinal cord
that go to control the arm and the hand have been ripped right out.
There is no connection with the brain.
So far, no-one has figured out how to plug nerves back into the spinal cord.
The team will need to patch in somewhere else.
This looks fairly scarred in here as well.
So we do a somewhat heroic manoeuvre where we go down
and we take some of the nerves that normally feed the ribs,
normally feed the muscles in-between the ribs and help you breathe.
We're using those nerves now to eventually make his arm move.
Jason's nerves don't reach from his ribs to his arms
so first they'll have to get extra wiring from his leg.
So l'm harvesting the splicing wire now from his leg that we're gonna use.
Trading what will become a scar and a numb patch on his foot for a bend at his elbow.
lf the nerves take his left arm's only connection to his brain
will be through the breathing muscles in his ribs.
That means with every breath Jason takes his arm will bend.
Every breath. That will only last perhaps six months.
Then the brain will relearn and stop doing that.
lt will take time before we know how much movement Jason will get back.
Axons,. the fibres extending from the nerve cells that carry electrical signals
grow about an inch a month.
Jason is receiving about nine inches worth.
So if all goes well, he'll have some feeling and motion return within the year.
He went through a heck of an operation.
l'm sure he's going to have a lot of pain from it, a lot of expense from it.
But to him, if this works, l suspect it will be worth it.
Nerves to muscles - the system is a marvel to behold.
But whether we're competing at the Olympic level
or simply making dinner plans and picking up groceries,
the whole thing would be absolutely useless without an infrastructure.
Follow any muscle to its base, through a bundle of strong, flexible fibres called tendons,
down to the very point where it's anchored
and you'll find one of the world's most remarkable materials - bone.
Some 206 of these engineering marvels are strewn throughout the body.
Strong enough to support up to 20 times our body weight,
light enough to defy gravity - however briefly,
flexible enough to absorb unfathomable impacts
and connected in such a way as to provide a seemingly endless range of movement.
Accounting for some 1 5 percent of our body mass,
bones are what give us our shape.
(Squelching)
Without them, we would all look like this.
But despite the amazing strength and support our inner frameworks provide,
they're usually portrayed in a more sinister manner.
Descend 60 feet under the streets of Paris to its catacombs hundreds of years old
and we get the stereotypical image of bone.
Dry, sterile,
white,
dead.
That's not exactly surprising.
This is the only way most of us ever to get see bones.
And these are the only bits of us that are going to be left.
This was the world's first glimpse of bone inside a living human body.
The left hand of Frau Bertha Roentgen
as imaged in 1 895 by her husband Wilhelm Roentgen, discoverer of the X-ray.
We've come a long way since then and it turns out bones are anything but dry.
Deep in the centre of many bones, in this tissue called the marrow,
some 1 20 million oxygen-carrying red blood cells
and seven million microbe-fighting white blood cells are born every minute
and shipped off to the rest of the body.
Toward the surface, specialised cells continually lay down new bone
while others do the opposite and whisk away old layers.
This is how bone grows with us throughout our youth
and keeps itself strong long after we're grown.
lf we suck away all that marrow, we see bone is mainly a blend of two substances -
the mineral calcium phosphate and the protein collagen.
lt's a match made in heaven.
Without flexible collagen, bone would be as brittle as glass.
Without calcium phosphate, it would be as unstructured as rubber.
Together they're light enough to manoeuvre,
strong enough to shelter our most delicate inner organs
and resilient enough to last a lifetime.
Go!
Champion gymnasts like Joey Hagerty routinely push the limits of bone.
They train them to grow and adapt to extremes.
OK, Joe. Ready? Three...
Sports physiologist Bill Sands tries to ensure this isn't past the breaking point.
Bone are living tissue like all other living tissues, so the things we ask the tissue to do,
as long as we provide those stimuli carefully, slowly, progressively,
we can usually get tissues to withstand astonishing things.
lt is this adaptive property of bone that allows a martial arts expert to punch through concrete.
SANDS: You don't do that the first day, of course.
You have to build them up more and more and more over multiple years.
The same goes for gymnasts whose bones absorb a tremendous amount of shock.
Yeah, don't hook your toes.
Sands uses a variety of apparatuses to measure this,.
like these inserts that measure the forces on Joey's feet,
and high-speed cameras to record the impact.
Ready? Three, two, one.
Go.
Well, right here he's over 1 50lbs per square inch.
Trust me, that's a big force.
The forces generally seen in gymnastics are the biggest forces we've had recorded so far.
1 4 to 20 times body weight.
The unsung heroes of all this movement are not our bones, but what brings them together.
lngenious devices called joints.
From our knees to our knuckles,
some 1 87 separate joints allow our bones to slide back and forth,
side to side, up, down,
and round and round like a well-oiled machine.
While bones have an almost miraculous tendency to heal,
joints are prone to break down.
Hey, Mark, how you doing?
The surgery that we're going to be doing today is to go through...
Whether it's due to football, weight-lifting or biking,
45-year-old Mark Kramer has had eight shoulder operations
over the last decade and a half.
Pretty easy.
Today, Dr Carl Basamania and his team at the Duke University Medical Center
will give him his ninth.
Number one: l hope to be out of pain.
When you live with pain every day it makes life challenging.
(Monitor beeps)
Basamania first assesses the damage to Mark's shoulder with an arthroscopic camera.
He discovers one of the tendons
that is supposed to hold the ball and socket joint of Mark's shoulder in place is eroding,
causing Mark intense pain.
l can show you on the X-ray, but the ball is sitting quite a way forward now,
because there's nothing to really hold it in place.
Basamania wants more than to simply pop Mark's shoulder back into place.
He wants to keep it there.
And to do that he'll turn to this -
a specially engineered biological material called extracellular matrix, or ECM,
that has the power to regenerate tissue.
Suck away the cells from just about any tissue in the body
and ECM is what will be left.
Mother Nature's done a really good job of bringing this material together.
Stephen Badylak of Pittsburgh's McGowan lnstitute for Regenerative Medicine
helped discover ECM's power,
which, like stem cells, has the potential to heal many tissues in the body.
The real magic of the material, if you wanna call it magic,
is that this is loaded with signalling molecules
that instruct the surrounding cells and tissues to heal in a specific way.
So if we examine...
The best part is that extracellular matrix is found in all animals.
Pig ECM, for example, is not that different from human ECM.
lt's not that much different than a mouse or a dinosaur's as far as that goes.
Therefore, when we take ECM from one species and put it in another,
it tends to be accepted as self.
We can even extract the material from one tissue, like pig's small intestine,
and put it into another like Mark Kramer's shoulder.
We're going to have graft, tendon and then more graft.
This is what l refer to as a taco repair, simply cos it looks like a taco.
Basamania simply wraps the material around Mark's damaged tendon
and sutures it into place.
Mark's own cells will then attach to the graft
and then within weeks his own body will reconstruct the tissue and heal itself.
For me this is very satisfying to go from a flimsy material
to now he has what looks like a very nice healthy-looking tendon.
Oh, he'll be back in the gym before too long.
Extracellular matrix has already been used to grow and treat things
like the oesophagus, skin, bladder.
Even to heal the damaged dorsal fin of a dolphin.
This idea of coaxing the body to fix itself may offer a whole new way to treat disease.
Salamanders and newts and starfish can regrow entire legs. Why can't we do it?
Our goal is to tell the body, ''We don't want you to just heal this tissue again.
We want you to reconstruct this tissue.''
Perhaps one day we will grow a new arm or leg as easily as a wounded starfish does.
For now, we're stuck with the limbs our parents gave us.
And as the sun sets on our day,
just getting two incredible machines to reproduce at all is challenge enough.
( Violin plays a tango)
lt's a simple biological function.
The swapping of genetic material to improve the adaptability of the species.
But getting together is anything but easy.
The seduction.
The courtship.
The commitment.
lt's all part of an intricate dance originated millions of years ago
and choreographed over countless generations.
So why all the fuss?
Why don't humans simply do as an amoeba does?
Just split in two.
lf all we wanted was to make exact copies of ourselves that is exactly what we would do.
But humans, along with practically the entire animal kingdom,
want more out of life than to simply survive.
We're built to thrive
and mixing up genes through sexual reproduction is the best way to do it.
The dance may begin with an attractive sight.
A smell, a touch.
Soon enough the heart beats faster, blood pressure rises.
Breathing accelerates.
Skin gets flushed.
And whether or not baby-making is on the agenda tonight,
the baby-making machinery is raring to go.
Every second of every day, a man produces more than 1,000 sperm.
That's 60,000 sperm per minute or 1 4 million during the course of an evening.
They may only be about two-thousandths of an inch long,
but 300 million are always ready to fulfil their life's mission -
to fertilise...one of these.
Unlike a man, a woman is born with her allotment of sex cells, about one million of them.
Only about 400 eggs will ever get released,
less than half the sperm cells a man produces every second.
Once the egg is pushed out of the ovary each month,
it's swooped into the fallopian tube for about a day,.
life's window of opportunity.
lf no suitor appears the egg dissolves.
But far more interesting is what happens when one does.
Of the millions of sperm engaged in this genetic race
only a few will defy all the odds and glimpse the finish line.
And as the body's smallest cells meet the largest, only one will make it across.
There was a time just a few centuries ago,
when some scholars believed that every sperm cell had a fully-formed miniature person inside
called a homunculus.
(Babies laugh and gurgle)
We now confidently know this is not the case.
Deep within each of the body's 1 00 trillion cells
is a complete blueprint for a human being - a genome.
Here our DNA molecules are tightly packaged into bundles called chromosomes.
Each cell has 23 pairs of chromosomes.
Sperm and egg cells, though, only have half a blueprint each.
They need each other.
And during that fateful meeting, their DNA fuses,
mingling the mother and the father's genetic traits.
For several days, the fertilised egg journeys through the fallopian tube towards the uterus,
growing and dividing along the way.
About 20 hours after fertilisation, it divides into two cells.
ln 48 hours, four. 1 2 hours later, it's eight cells.
And by 72 hours, it's 1 6.
Each of the new cells is genetically identical to the original.
At this stage everything from eye and hair colour, gender,
and even to some extent height, weight, intelligence, sense of humour and personality,
are all pre-determined.
ln fact, scientists can even sift through a dish of embryos to choose gender
or identify genetic defects and remove them.
But not if couples have a baby the old-fashioned way.
By the end of the first week, the free-floating ball of cells, now known as a blastocyst,
has entered the uterus.
Cells continue to divide here before they find a place to settle.
lt's official,. she is pregnant.
As the weeks pass, cells start to specialise and forms begin to take shape.
At three weeks a groove marks the beginning of a nervous system,
the top of the tube destined to become a brain and the lower portion the spinal cord.
By eight weeks, almost all of the organs and systems
in this walnut-sized embryo are in place, earning it by week nine the official title of foetus.
And now growth really kicks in.
By 1 2 weeks, just as expectant parents get their first glimpse into the watery womb,
the foetus may practise breathing, taking in amniotic fluid instead of air.
Already it can punch and kick.
At 1 4 weeks, it can swallow and suck its thumb.
(Woman laughs)
By 24, it can hear.
By 32, it responds to music, voices.
OK, so that's... Oh, there's her eyes.
That's eyes, nose, mouth.
Now her mouth is wide open.
And at 40 weeks, give or take, it's ready to enter the world.
Push.
- Ten, nine. Ten. - (Exhales heavily)
- That's it. - Now push.
Great, great. Great, honey.
Another push.
- Oh, my God. - There's your baby.
Good job!
22:30.
- Oh, my God. - Good job.
- 1 0:31 . - There you go.
Oh, my gosh.
(Air hisses)
(Cries)
- lt's a big girl. - lt's a big girl.
ln the nine months it takes her to go from fertilised egg to fully formed human baby
she will have grown more than 5,000 times bigger.
As women around the globe can attest, getting to this point is no easy task.
And yet some 260 humans are born this way every minute.
That's 37 4,000 every day and more than 1 36 million every year.
(Laughter)
Why evolve such a painful and risky way to keep a species going?
lt's the price we pay for our giant brains.
Hi.
Billions of neurons are buzzing around in that head of hers,
virtually all the nerve cells her brain will ever need.
Throughout her childhood they'll be reaching out to other neurons,
making more connections with each new experience.
With each connection mind and body fuse to form the thing that is us.
And at the helm, the most remarkable command centre in the world.
Every system in the body is complex, but there is only one presiding over everything we do.
Every second since our day began,
our brains have been guiding, guarding and giving orders.
Defining nothing less than what we are.
Through an information superhighway of nerves fanning throughout our bodies
our brains keep tabs on every part of us -
eyes and ears, skin and bones, heart and muscles.
Through a hundred billion specialised cells called neurons
zapping millions of electrical and chemical signals at up to 200 miles per hour
these three-pound blobs of fat and water let us think, feel, want, remember and react.
lt really is what makes us human,
because it encapsulates everything from our ability to paint a beautiful picture
to construct a building,
to render violence on somebody else.
lf l transplant your heart, for example, you're still you.
But if we do something that damages your brain,
the very character, your very personality may change.
And so the brain is you.
And when this unremarkable-looking organ is under assault,
everything that defines you is at risk.
Hi, Brandon. This is Dr Liau. They're gonna be putting you to sleep now, OK?
- OK. - l'll see you when you wake up.
Everyone in this UCLA operating room is acutely aware of the brain's vulnerability.
23-year-old Brandon Carson has a large cancerous tumour
near a region of his brain critical for language.
His tumour is very close to Broca's area.
(Whirring)
lt's probably one of the closer ones l've seen.
The challenge to Dr Linda Liau and the team of doctors
is to remove the tumour whilst keeping Brandon's speech intact.
Brandon, wake up.
Which is why once they've opened his skull and revealed his brain
the doctors do their best to keep Brandon awake.
Brandon, open your eyes.
The brain doesn't have pain receptors, so Brandon doesn't feel anything,
even when they do wake him up.
- Give it a try. - Brandon.
(Low conversation)
- No, no. - No, you can't.
Don't sit up.
Can we do this test real quick?
DR LlAU: Language is a function we can't map when a patient is asleep.
We can measure muscle and things like that,
but we can't really with a 1 00% certainty know where his language areas are
unless we wake him up and stimulate those particular areas.
OK. What's this?
Good. And this one?
Using easily-identifiable flash cards, a psychologist tests Brandon's language capacity.
Simultaneously, Liau disrupts tiny areas of his language centre with a mild electric shock.
Let's try that same area again.
lf Brandon has trouble recognising these images while the shock is being delivered,
the team then knows this is a critical area and makes sure to work around it.
Jessica, there's an area that l think is safe.
l'm going to start there and you just keep talking to him.
By imaging the brain before and during surgery, something she couldn't do just ten years ago,
Liau can cut out the tumour with confidence.
And with a living, functioning, awake brain exposed,
neuroscientists get a rare opportunity to peer inside down to individual blood vessels
and glimpse the mysterious organ in action.
Mapping the human brain is a Holy Grail - we all want to do it.
We want to create a map where we know what structures are where
and what the function is in those structures.
But unlike the map of the Earth where there's latitude and longitude and so forth,
the human brain is individualised.
Each is different from the other; it's what makes us unique.
At UCLA's Laboratory of Neuro lmaging,
Dr Arthur Toga isjust beginning to understand these differences
with what is called the Brain Atlas.
lt's a collection of thousands and thousands of scans of human subjects.
Various ages, various groups, various genders.
With it, we can watch a brain develop from five years old to 90
and see it start to degrade during middle age.
Comparing a man and a woman's brain.
His may have more volume but hers has added surface area.
Here's the brain activity of someone who speaks one language, and someone who speaks two.
A right-hander and a left.
The Brain Atlas looks at our master organ from a variety of perspectives,
right down to individual neurons.
Through functional magnetic resonance imaging, or FMRl,
we can see the exact spots where conscious thoughts originate as they form.
Navigating a map, listening to music, experiencing fear and laughter.
This is remarkable.
You can watch the human brain function in a normal, living individual.
FMRl also allows us to watch the brain as it malfunctions.
Two years ago a severe car crash left 22-year-old Kimberlee Lizarraga
crippled by pain in her neck and shoulders, and she feels it to this day.
Just picking up groceries or driving a car can be excruciating.
The pain that l felt was so unexplainable. l can't even explain the pain that l felt.
lt affects my job, it affects my whole life tremendously.
Kimberlee suffered no brain trauma in the accident and her injuries are completely healed.
Her pain lives only in her brain.
And with the help of Stanford's Dr Sean Mackey and an FMRl, Kimberlee is learning to control it.
Pain doesn't live in one region.
We believe it is ultimately a flow of information, a flow of neural activity
between a multitude of regions within the brain.
What we're working on now is actually trying to control the volume on... the faucet,
so to speak, on information flowing back and forth.
Mackey doesn't want to stop that flow completely.
Pain does have its place.
What's wonderful about pain is that it's so terrible.
My son only had to touch a hot stove once to learn not to do it.
The problem is when pain becomes chronic.
When it lasts beyond the time you would expect for the tissue to have healed after an injury.
lt's persistent. lt robs our soul, it robs of who we are.
All right, Kimberlee, we're going to take anatomical images of your brain.
This is gonna take about two minutes.
Which explains why Kimberlee submits to the confines of this claustrophobic machine.
While she's in there the Stanford team gives her a real-time picture
of the activity in her brain's pain areas.
Represented by either a line graph or a flame.
By simply thinking about putting those flames out,
Kimberlee is, for the first time, putting her pain out.
The idea is to drive the activity down.
And in doing so, we also hope to see that the flame goes down.
We still don't understand how the brain does this.
But one thing is clear,.
we can physically change the activity in our brains and the FMRl lets us watch.
What we showed here is that you can actually focus on a particular region,
a particular area, and learn to control that.
And that's the first time this has been done.
This new-found power over our brains has applications well beyond pain
to mental illnesses like depression, phobias and addiction.
Our brains are highly malleable, plastic, changeable.
We really can control and change our brain.
And so the opportunities are truly limitless,
because there's no area of the brain that we can't now tap into
and have somebody learn how to control it.
What's news to neuroscientists has been practised by others for thousands of years.
Using nothing but simple meditation, some of us have already learned how to control the brain.
Our brains enable us to do extraordinary things,
but some are much better than others at harnessing its power.
Buddhist monks have used their brains to dry wet sheets on their backs,
slow their heart rates, or be incredibly resistant to pain.
For Souei Sakamoto, a Shingon Buddhist, it's meditating half an hour a day
under a frigid waterfall in Toyama, Japan.
A ritual that dates back hundreds of years.
(Speaks Japanese)
TRANSLATOR: We have an old saying in Japan;
''Clear your mind of all mundane thoughts and you'll find that even fire is cool.''
When you learn to control your brain it may be possible to use the brain
to influence the body in very unusual ways.
To understand the brain's power
Richard Davidson of the University of Wisconsin-Madison
studies the effects of meditation on Buddhist monks.
Specifically, measuring how their ancient practices physically change their brains.
These are individuals who we can think of as the Olympic athletes of meditation.
They have spent years cultivating certain qualities of mind
and they are virtuosos in many respects.
This is just to keep any water that might drip down from getting on your clothing.
- Oh. - A little bit of water might drip on you.
East meets West in Davidson's lab
as FMRls, PETscans and electroencephalograms, or EEGs,
which involve this unusual contraption,
are all aimed at monks deep in meditation.
Today it's 84-year-old Geshe Lhundab Sopa,
who's been an ordained Tibetan monk since 1 932.
You have an interesting new hat, Geshe. You look very futuristic.
By attaching these 1 28 wire-laden sponges to Geshe Sopa's head,
the Wisconsin team can record the tiny electrical currents
that continuously emanate through his scalp.
A measure of the millions of neurons firing away in his brain at any given moment.
He'll begin with a traditional compassion meditation.
So we'll begin in the neutral state, Geshe,
and l'll let you know when to begin the compassion meditation.
Experienced meditators can enter a deep, meditative state in less than 20 seconds
and with the EEG we can watch as it happens.
Compassion, compassion.
Just at the start of the transition when a practitioner begins to meditate
there is a very discernible change in these brain signals.
And together with FMRl data,
Davidson has located these changes in several areas of the brain
including the prefrontal cortex.
So this is an area here that is in the left prefrontal cortex,
that we find more activated in the practitioners,
particularly when they're generating this compassion meditation.
Left activity in this region is associated with enthusiasm and happiness,
right with negativity and stress.
By meditating these monks are able to shift their neurons'activity from right to left.
DAVlDSON: These changes are changes that have not been seen before
and so this opens up whole vistas of new possibilities
that we're only just beginning to scratch the surface with.
Already, Davidson and others have found that meditation's effects on brain activity
can lower levels of stress hormones and boost immune function.
And for as little as two minutes three times a day
he believes even those on a much lower plane of enlightenment can reap these benefits too.
Whether we control them or they control us,
our brains more than anything else set us apart from all other species,
and one another.
But thought, feeling and selfhood are fragile.
Though it's only about 2% of our body weight, the brain exhausts 20% of our oxygen.
lf the brain is without oxygen for just ten seconds we lose consciousness.
Four minutes, and the damage can be permanent.
And unlike other cells in the body,
when neurons get badly damaged they cannot be replaced.
WOMAN: (over speakerphone) OK, this is the result for patient Carson, Brandon.
For section No.1 left frontal tumour, the diagnosis is...
At UCLA Dr Linda Liau continues to work on 23-year-old Brandon Carson.
After mapping the speech areas of his brain, she's ready to remove a cancerous tumour.
That darkened mass, yes.
What l'm trying to do is dissect around it.
As an electronic scalpel cuts into his brain Brandon is still responding to those flash cards.
Not a scrap of cancerous tissue can stay.
And just the tiniest sliver of brain can be removed.
There's some deeper parts of the tumour that are near blood vessels,
and, obviously, we don't want to take out any necessary blood vessels.
The only way we could see that is through the microscope.
This is the hole where the tumour used to be.
Thanks to these new real-time glimpses into the brain
Brandon will soon wake up from his surgery, tumour-free and speech intact.
We inch one step closer to understanding how it all works
and how far we still have to go.
l think that as you learn, you know, where vision is
and where l control my hand from and where my speech is located,
you begin to feel like, ''l'm understanding this circuitry.
l think l understand how the brain works.''
And then you get into it a little more deeply
and you realise you don't know very much at all.
That the wonder of the human brain is sort of one of these great frontiers. That's the truth.
The more you learn the dumber you realise you are.
The same applies to all parts of the incredible machine.
Whether it's our control centre or pumping station,
our security or exhaust system,
our power plants or copying machines,
the human body has been a marvel of complexity for more than 1 00,000 years.
From its surface to its core, amongst its trillions of cells,
and throughout its roadways and circuitry,
at the end of the day,
somehow all of these systems converge into one truly incredible design.
Even while we sleep, our bodies are always working, always breathing, always beating,
always ready to begin another day.
And though there may be an infinite number of species born of stars long gone,
we can all rest easy knowing there is nothing quite like the incredible human machine.