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  • I'm going to take you on a journey

  • into some hidden worlds inside your own body

  • using the scanning electron microscope.

  • These microscopes use a beam of electrons

  • to illuminate things that are too small

  • to be seen by the photons of visible light.

  • And to put this in context,

  • if you mentally divide one tiny millimeter

  • into a thousand parts,

  • each one of those parts is a micrometer,

  • or micron for short.

  • If you then divide one micron

  • into another thousand parts,

  • each one of those is a nanometer.

  • And it's nanometers and microns

  • that are the domain

  • of the scanning electron microscope.

  • So, let's start with something on the body

  • that we can measure at about 100 microns wide,

  • and that would be a human hair,

  • which now you can see is covered with scales,

  • just like all of our hairs,

  • and in fact, just like all mammal hairs.

  • We're going to plunge into the body now,

  • and we've landed in the thyroid gland.

  • Here we're looking at proteins

  • that are being secreted into a storage chamber

  • where they are going to develop

  • into the mature thyroid hormones

  • before being released into the body.

  • And at this point you might be wondering

  • if these colors are real.

  • The answer is no.

  • Electron images only happen in black and white.

  • I often colorize my images for various reasons,

  • but I don't change the structures,

  • so the strucutres that you're seeing

  • are all exactly as they were

  • when I photographed them in the microscope.

  • We're going to take a detour

  • and zoom in on the heart muscle now.

  • And the heart muscle has this curious structure

  • that's kind of like corrugated cardboard.

  • That's what allows the heart to expand and contract as it's beating.

  • Let's go look at a lung with pneumonia.

  • Here we've got a white blood cell

  • poking around in an air sac,

  • looking for something to clean out

  • like a little vacuum cleaner.

  • This is your immune systems at work.

  • So what are the kinds of things

  • that we don't want to be breathing,

  • besides bacteria and viruses?

  • Well, we all know to stay away from asbestos

  • and now we can see why.

  • This is a close-up view of the mineral

  • that asbestos is made from,

  • and now you can see that it's composed of

  • many tiny, fine little needles.

  • Each one of those needles is a single crystal.

  • And in this picture, they're begininng to pry apart

  • and tangle up into a spiky mess,

  • not for breathing.

  • What else might we want to avoid breathing?

  • Well, how about diesel fuel?

  • We're looking here at the particles of diesel soot,

  • and these are extraordinarily tiny.

  • In fact, each one of these little particles

  • is only about 50 nanometers wide.

  • We'll go and look at some blood now.

  • We've got a collection

  • of nice, fat, happy, healthy red blood cells,

  • but they're all tangled up in a network of fibers.

  • This is how the body makes a blood clot.

  • And so, it surrounds a group of red blood cells

  • and other cells, and traps them

  • so the blood can't flow.

  • We've got two more blood cells here,

  • but they're not normal

  • like the ones in the blood clot image.

  • These are distorted.

  • You can see that they're curling up

  • and beginning to grow what's going to become spikes.

  • These are sickle cells

  • and these are what cause the condition

  • of sickle cell amenia.

  • We've gone into the mouth now

  • and we've landed on dental plaque,

  • which you can see is covered with bacteria,

  • and in fact dental plaque is host

  • to about 1,000 different species of bacteria.

  • Lovely to think about.

  • And now we are on to other teeth.

  • We're on the surfaces of the,

  • or the internal surfaces of the teeth themselves.

  • The smaller one is a baby tooth

  • that had just fallen out of the mouth

  • of a young friend of mine,

  • and I want to call your attention to the little holes.

  • Those little holes are the tops

  • of a whole network of tiny little tubes

  • that circulate nourishing fluids inside your teeth.

  • And we can see those tubes

  • a little better in the larger picture

  • because some of them are in cross-section.

  • But in fact, this larger picture is showing you

  • a portion of a tusk, which you may know

  • is simply a great big, elongated tooth,

  • so you would expect to see the same features

  • between your teeth and a tusk.

  • But that larger tusk picture is also rough

  • by comparison to the young baby tooth.

  • That's because it's many, many thousands of years old.

  • It's also partly fossilized.

  • And, between these two pictures,

  • now you can see how your teeth relate

  • to the tusk of an Ice Age mammoth.

  • We're shooting up north now into the brain,

  • and we can see these pink cells down at the bottom.

  • Those are the neurons of memory.

  • And I'm going to leave you with this picture

  • because I know you're going to take

  • a lot of happy memories away

  • from your exciting day at TED

  • and now you can visualize where those memories

  • are being stored in your own brain.

  • Thank you.

I'm going to take you on a journey

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B2 US TED-Ed tusk blood teeth microscope electron

【TED-Ed】Visualizing hidden worlds inside your body - Dee Breger

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    wikiHuang posted on 2014/09/12
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