Incredible Human Machine Page #4

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.

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