The Human Body

If we take a line of people,

one from each year of life from birth to a hundred,

what we see is the remarkable development of human ageing.

As we journey through the first stages of our lives,

our bodies develop to meet the challenges of each new age.

Year by year, we're continually developing, growing stronger,

becoming more intellectually alert

and more sexually mature.

All these changes bring us to the point where we can reproduce,

and so pass on our genes to the next generation.

But what's particularly remarkable is that we go on.

0n beyond the child-bearing years and the years it takes to raise our children.

0n into the later years.

It's remarkable because in this respect we're unlike any other animals.

In the wild, animals don't grow old,

but we humans have evolved to live long lives -

longer than any other mammal, in fact.

Why is something of a mystery, but for humans at least,

there might be something more to growing old than a slow decline.

Believe it or not, that's my heart beating there.

I'm wired up to a cardiac monitor.

At the beginning of the century, there was a theory about ageing which was very popular.

It was called the ''Rate of Living'' theory.

It argued that each animal had a finite number of heartbeats,

about one to two billion.

So, for example, a hare, whose heart beats very fast,

might live from three to five years, a victim of live fast die young.

A tortoise, whose heart beats very slowly, might live for over a century.

I'm not quite sure where that leaves me.

Anyway, the theory was wrong.

The truth is we don't really understand very much about the ageing process.

But what we do know is very interesting.

We'll see why a great French painter gradually altered the way he painted his garden,

and how an eighty-year-old cowboy can still ride a horse.

How sex hormones affect the way we age.

What we have in common with Voyager.

Why very familiar sounds are heard differently as time goes by.

And why I don't look the way I did when I first heard this music.

But science can only give us part of the picture.

So we'll be following the story of two people

who are actually living through the experience of growing older.

They are an elderly couple living in a farming community in mid-west America.

Bud Mather is still herding cattle

at the age of almost eighty.

He and his wife Viola have grown old together

on their farm in Kansas.

We've been here ever since we married, 45 years ago.

And we've never been gone more than 20 days, I guess.

This place when we got married was just a little four-room side house.

It didn't have any water in it, it didn't have any bathroom.

We just had to carry all the water in and out,

and er, that's why you married me, so I'd cook for you because you couldn't cook.

And you didn't want to haul the water.

You married me so I'd take care of you, didn't ya?

Yeah.

I'll be 78 in November,

and Vi, she was 63 in August.

That's about 14 years difference in us.

When we was going together, they always kid me about it:

Ageing is a process they've shared

since they first met each other at a dance at the old schoolhouse almost half a century ago.

Boy, this place is a mess now, ain't it?

I can't believe... look at the terrible shape it's in.

All the windows are gone.

Wasn't like this when we met 50...

- Yeah. - Seems like 50, doesn't it?

- 46 years ago. - 46 years ago, yeah.

- We met here at a dance, remember that? - Oh, yeah.

On the night of the dance that we met, this place was full of people.

Music, laughter, and people having a good time.

And he came over and asked me to dance.

I thought he had the bluest eyes I had ever seen.

And I fell in love with those blue eyes.

She sure looked wonderful to me. Her skin was real fair and smooth.

And I guess I fell in love with her then.

As we grow on through the years, we get a little more here and a little more there,

and a little less here and a little less there.

But I don't think our love has got any less.

If anything, it's got deeper, more understanding of one another.

Naturally, over the years, Bud and Viola have experienced some of the changes

that tend to happen to us as we grow older.

The first time I realised I needed glasses, we were driving in the car.

Bud was driving and it was late in the evening.

Well, I got the glasses, I put them on, and I have never taken them off again.

Eyesight is so remarkably and wonderfully complex

that it's arguably our most important sense.

Using a special camera, it's possible to look directly into the eye.

The pupil has been enlarged so that we're looking straight through the lens of the eye,

at the pink retina at the back - pink because of the blood vessels immediately behind it.

This is what produces the familiar red eye in flash photos.

It's the retina that carries the receptors that register the light from the scene in front of us.

For such a complex system, it's remarkable how much

our brains have to compensate for what we actually see.

The lens in our eye produces an image on the retina which is actually upside down.

0ur brains correct this by telling us that what we're seeing is the right way up.

The lens itself is pretty basic.

It tends to produce an image which is blurred, particularly around the edges.

But when it comes to focusing, it's not just the lens that matters, it's the retina.

0n the retina, the white spot with blood vessels emerging is the optic nerve.

This carries the visual signals to the brain.

But the part that does the most work is the small dark circular area

in the centre of the picture.

It's called the macula and it's only about one to two millimetres across.

Right in the middle of that area, best seen in a green light,

is a small pit with a yellow spot in the middle.

It's called the fovea - this is what gives us a focused image.

Every time we look at something and see it in sharp focus,

it's not the rest of the retina that's doing it, it's just that small spot,

only a fifth of a millimetre across, that gives us that focused image.

But because it's so small, what it sees in focus is only a small part of the scene in front of us.

So the way we view something like this is to move the eyes around,

seeing one small focused area after another.

The brain receives these images

and persuades us that everything in front of us is in focus.

But it's an illusion.

As we get older, our brain has to do more and more work.

When we're children, the lens in our eye has a very pale blue colour.

By middle age, in many people the coloration is getting stronger.

It's going yellow, and by old age it can even be brown.

But at all stages, the brain corrects and takes out that coloration,

so that we're totally unaware of it.

And there's something else going on. At the front of the eye is the coloured iris,

and immediately behind it is the lens.

In the eye of a small child, the lens is almost completely clear.

But it's at the start of an extremely gradual process that affects us all.

An eye at the age of eleven. By twenty it's become a little bit cloudy.

At 45, more so.

At 80, definitely.

As we get older, we don't notice this cloudiness developing,

because we simply can't remember how clearly we could once see things.

But if it gets too cloudy, there's a limit to what the brain can adjust for.

It doesn't happen to most people,

but the lens in an extremely cloudy condition is called a cataract.

It's so cloudy, other people can see it.

The effects of cataracts were particularly important

for what happened in this garden some years ago.

Earlier this century, the man who lived here at Giverny in Northern France

experienced many of these changes to his eyesight.

In his case it was particularly important,

because he was one of the greatest French painters of all time, Claude Monet.

0ver the years, he painted many scenes in these gardens.

Not only are they masterpieces, but they provide

a remarkable record of what was happening as age affects eyesight.

What is noticeable is that his paintings mysteriously began to change.

They became redder and redder.

The reason - he was developing cataracts in both his eyes.

These not only affected the sharpness of what he could see, but the way he saw the colours.

In 1923, Monet had an operation to remove the cloudy lens from his right eye.

It instantly changed the way he saw things.

Shortly afterwards, he painted this scene with the eye that still had the cataract in it,

and then again, the same scene with the other eye where the cataract had been removed.

What he saw with the cataract eye was this.

And what he saw with the other eye where the cataract had been removed was this.

It has much more blue in it.

A close-up of the tree makes it obvious. The left eye with the cataract still in,

and the right eye with it removed.

Monet was so horrified

by the colours he had used when his vision was affected by the cataracts,

he wanted to alter many of his paintings, and even destroyed some of them.

Coping with the changes that accompany ageing needn't be depressing.

The effects of growing older certainly don't bother these people too much.

They're Bud and Viola's friends,

and they all go back to that same dance at the school hall,

where Bud and Viola met nearly fifty years ago.

It's been really nice to get together.

It's about like it was back at the old schoolhouse. Same bunch.

Well, we had a lot of fun then. A lot of things we can't talk about.

There are people who hate to turn 40,

50 and 60, because they think

that they're getting old. Look at Bud Mather.

Now, he isn't old. I mean the years might say that he's old, but he's got a lot in him yet.

You know what I remember about Bud?

He had the prettiest, waviest hair.

- And that's different now, isn't it? - Yes, it is.

And his skin was smooth, no wrinkles. And he didn't have any little pot here.

And he didn't have any false teeth.

Bud's skin might not be as soft as it once was,

but he's still not doing that badly considering his job.

As a cattle rancher, his occupational hazard is the sun.

It can be extremely damaging to skin, because it gradually destroys what supports it.

Even those who tan easily will have skins prematurely wrinkled.

Regardless of any damage caused by the sun, normal ageing produces changes in the skin.

This ultrasound probe sends out high-frequency sound

that bounces back from the layers just under the surface.

A young person will, on average, have skin about half a millimetre thick.

An older person tends to have thinner skin.

A young person's skin is on the left of the screen,

and an old person on the right.

Typically, it's about twenty five percent thinner.

The reason is the older skin has lost substances

known as collagen and elastin. These are proteins which provide

the underlying framework of a young, healthy skin.

Sunlight accelerates the loss of these proteins, and it's thought smoking has a similar effect.

The skin becomes less elastic,

and the continual flexing of facial muscles gradually produces wrinkles.

It's been estimated that two hundred thousand frowns are enough to etch in one brow line.

0ne way to test the age of the skin is to pinch the back of the hand and watch what happens.

Young skin springs back quickly.

By the time we've reached our thirties and forties, it's getting a little slower.

And old skin definitely takes its time.