The Human Body

Childhood - from newborn baby to infant.

From toddler to the first day at school.

To crawl, to walk, to talk, to become an individual,

it is four years of miraculous achievement.

Never again will the human body change so fast or learn so much.

This is the story of that remarkable time.

It all begins with the most treacherous journey of our lives,

from our mother's womb to the outside world.

As recently as Victorian times, one in 20 babies died during birth.

Death affected everybody, including royalty.

Here in Windsor Castle is a memorial to Princess Charlotte and her son.

Just one year after her marriage in 1816, she was expecting a baby.

Tragically, the birth was a disaster.

The baby boy became stuck inside his mother.

After two days and two nights of labour, the unborn prince was dead,

and a few hours later, Charlotte died as well.

Their deaths meant the crown eventually passed to Queen Victoria, and the rest is history.

With modern medicine, Princess Charlotte almost certainly would have survived,

and her little boy would have become king.

Today in Britain, very few babies will die.

But that journey, just ten centimetres in length, remains as fraught with danger as ever.

Go on, Jane.

For nine months, the baby's been fully equipped for life in the warm liquid world of the womb,

relying on its mother for food and oxygen.

It's in for a rude shock.

As the baby is squeezed down the birth canal, dramatic changes have to happen.

The key to success is the trauma of the birth itself.

It's so severe, the baby has adrenalin levels

even higher than that of a person suffering a heart attack.

This rush of adrenalin will kick-start the baby's breathing.

Well done, that's brilliant. Here he comes.

Yet even now during birth, the baby's windpipe and lungs are still full of liquid from the womb.

If they aren't quickly emptied, it will drown.

The fluid drains away as it's absorbed into the lung walls.

Air rushes in.

Life-giving oxygen can enter the blood vessels of the lungs.

The first breath triggers further upheavals inside the tiny body.

That's it, Jane. Well done, sweetheart. Well done.

Excellent! Well done! Well done.

Remarkably, even at this late stage,

the heart of the baby is not yet ready for life outside the womb.

In one of the interior walls of the heart there is a hole.

This opening was vital when the baby had to pump blood to the placenta.

Now it's a liability.

Blood flowing through a newly-opened vessel

will slam shut a flap of tissue to seal the vulnerable hole.

It forms a solid wall, and the four chambers of the heart are finally complete.

In an adult, such major changes would require open-heart surgery,

but here they are happening instantaneously and unseen inside the baby.

This is the miracle of birth.

Now we'll cut his cord. Can Richard cut the cord?

It's a boy - Bob.

The umbilical cord, the last link to his mother, is cut.

Bob's first challenge is to keep warm.

A heat-sensitive camera reveals the coldest parts as blue.

Bob's toes and nose suffer most.

The delivery room is 15 degrees colder than his mother's womb.

He looks fine. Yes!

A special type of fat is concentrated on his back and around his chest.

This baby fat can be broken down to release emergency heat.

But for the first six months of life, Bob's ability to control his temperature is very limited.

For the moment, he relies on blankets and cuddles.

He's shivering a bit.

You see his little lips going. He's cold. A little bit cold.

He looks...dark hair, yeah.

Those little marks will be gone by tomorrow.

It'll take no time at all. It was all a bit of a push.

Bob's tight squeeze through the birth canal has left his head an odd, pointed shape.

His skull is so pliable because the 22 different bones that make it up

haven't yet fused together, leaving holes between the bone plates.

Bob would never have made it out of the womb if his skull hadn't evolved to be this way.

From now on Bob will live under the watchful eye of his proud parents, Jane and Richard Jeffers.

His hazardous journey into the world is over.

- Thanks, Richard. That's brilliant. - There we are. Just pop him down here.

It's just amazing to see that he's perfectly formed

in absolutely every way, his arms, his legs.

He's got quite a tidy little nose.

He's got a nice mouth. He's got quite a wide mouth.

Everything is just perfect. It's just a miracle.

You don't see that they're wrinkled up and all those other things.

His face looks really quite well established

for a small baby. He's got a lot of character.

In a strange sort of way, he looks like a little old man.

Although Bob is helpless, he has a fantastic survival strategy.

Parents find their new baby irresistible.

Oh, Bob. Is that nappy bothering you?

They do control you to a point. Their demands are paramount.

If they cry and want feeding, you've got to do that.

If they need changing... You can't ignore their needs, because they're dependant on you.

This is the best bit, isn't it? A bit of fresh air to that bottom.

It's almost as if Bob has put his parents under a spell.

# You're just too good to be true

# Can't take my eyes off of you

# You'll be like heaven to touch

# And I want to hold you so much

# At long last love has arrived... #

Bob's...first...picture.

# You're just too good to be true

# Can't take my eyes off of you #

0ver a period of six months, we followed Bob's rapid development.

Just a few weeks after birth he was a bundle of reflexes,

a handy set of automatic responses that help him survive.

Can he hear you?

Yes, he's startled by loud noises, and he can definitely hear me.

A young baby will try to grip with his hands anything he touches.

Young apes grasp on to their mother's fur.

But even in hairless humans this grasping reflex can be useful for holding on.

I'm just going to check his reflexes.

A reflex is activated by any touch to the palm.

Here, the baby's hand has grasped a finger.

Inside the hand, you can see the muscles that even just after birth

can support the weight of the baby.

Ironically, the hardest thing for babies to learn is to let go.

Their fingers have to be prised open.

And Bob's toes will try to grip as well,

a throwback to our ape-like ancestors who held on to things with their feet.

These reflexes are completely involuntary.

They require no more conscious control than the contraction of the eye's pupil to light.

Are you ready? Ready for your milk?

Another reflex helps Bob find food.

Although he doesn't know where food comes from,

whenever something brushes his cheek he automatically turns his head from side to side

and parts his lips. This is the rooting reflex.

He just finds it himself.

He'll find it. You just need to put his head somewhere remotely near,

and he's there.

And that's not all. The milk that's produced in the mother's breast

can be activated merely by the sound of the baby crying.

That's a lovely boy.

Bob not only manipulates his mother's behaviour but also her body.

What a face. Got a full tummy there.

Newborn babies have another reflex which is much more mysterious.

In fact, it's an ability so odd that until recently we didn't even realise it existed.

Actually, it's a reflex we all had in the first six months of life.

Watch this.

It's called the diving reflex, because it stops the baby from breathing under water.

Wow.

She's more comfortable than I am, I think.

The mouth can be wide open,

but inside the baby the top of her lungs is sealed off,

and any water is diverted down the oesophagus into the stomach.

Perhaps more amazing are the baby's movements.

Not only do the arms and legs move in a coordinated stroke,

but the torso flexes enough to propel him through the water for over a metre.

However, after a few seconds

they all need adult help to regain the surface and the vital next breath.

Hey, up you go.

Some people believe these abilities come from a long-lost ancestor

who spent most of its time in the sea.

0thers think it is a hangover from our life in the liquid-filled womb.

The truth is we don't even understand the origins of this remarkable ability.

For the moment at least, it remains a delightful mystery.

As the baby's mind matures,

these involuntary reflexes are suppressed by conscious thoughts and movements.

This has already happened with Max, Bob's three-year-old brother.

The reflexes are no longer needed, so they eventually disappear.

In the buzzing, booming world,

both reflexes and conscious thoughts depend on the senses.

But at first Bob can see little. Contrast is poor.

Anything beyond half a metre is out of focus and blurred,

and he may even see double.

0ne of the reasons Bob is so bad at focusing is hidden inside the eyes.

A very young baby does not have proper control of the muscles

that change the shape of the lens.

The lens, here coloured white, is fixed at one set shape.

To focus on objects far away, the tiny muscles around the lens

need to stretch it into a thinner shape.

It'll be a while before Bob learns to do this.

Are you gonna try? Yes! Clever boy!

By two months, his vision will have improved.

He seems to like looking at faces best,

and it's at this time he will first smile,

a magic moment for any parent.

He still was only about three weeks.

Then I realised that he was actually smiling back at me.

Smiling and recognising a smile are crucial milestones.

So a team in London are finding out

what's going on inside the head of this baby girl to see how she does it.

You're a very good baby. Very smiley.

They measure the electrical activity in the brain when she looks at different faces.

A scowling face.

A smiling face.

And an upside-down face.

The patterns of brain waves prove that the baby first sees it as a face, right way up or not.

And then, a fraction of a second later,

she checks out what emotion is showing.

And these two tasks actually happen in different parts of the brain.

You might assume a baby's brain is just the same as an adult's, only smaller.

But it's not. A baby's brain is nowhere near finished.

New connections between the hundred billion brain cells are being made all the time.

Throughout babyhood, the brain is sculpted.

So our experiences in our first few years will determine the brain we have as adults.

This developing brain is so demanding

that over half of all the food Bob eats goes to driving it.

To supply this much energy, it is essential that he moves on from milk.

To deal with solid food, things are stirring underneath his gums.

His first teeth will grow up from tiny tooth buds

that have been hidden in his jaw since long before he was born.

But they won't start to burst through his gums until he's around six months old.

For the first time, over 40 days, this dramatic event has been filmed.