Name: 幹細胞物語 (A Stem Cell Story)
Uploaded: 2021-01-14T05:21:42.000Z
Duration: 15 min 53 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

We hear a lot about stem cells these days,

but what are they, where do they come from

Inside our bodies there's a microscopic world,

busy and complex like the world around us.

Stem cells build and maintain this world.

This is a story of stem cells and their lives

Life begins with one cell, the fertilised egg.

Throughout development cells divide over and over again

to produce the billions of cells that make up the body.

At certain stages, most cells stop making copies of themselves

When we are fully formed almost all our cells are specialised.

Cells are beautiful things when you see them down a microscope.

Normally they're so miniscule we can't see them,

And each type of cell has its own characteristic.

Some types of cell grow very closely together

Other types of cell will move away from one and other.

Some cells become big, others are always very small.

It depends on what type of cell they are.

These different cell types work in specialised teams.

Some carry oxygen through the blood system,

some do the stretching and contracting in our muscles,

some carry messages between our brain and the rest of our body.

Stem cells are very special cells They act as a resevoir,

So, if they die and get used up, they have to be replaced from somewhere.

And this is where the stem cells function.

We need to make millions of new blood cells every day

And these cells actually live in the bone marrow.

Altogether a blood stem cell can make eight different types

We need to make new skin cells all the time

because we're always wearing away our skin.

And actually now we know they're present even in the brain.

because otherwise we'd lose the capacity to make any new cells.

Every time it divides, it produces two daughter cells,

and those daughter cells can be new stem cells,

Stem cells in the adult tissues can normally only make

So a stem cell in the skin, can make cells in the skin,

but it can't make blood cells and vice versa.

Stem cells are already useful in medicine.

One skin stem cell alone can produce enough specialised skin stells

This produced a breakthrough in the treatment of extensive burns.

When a person is heavily burnt, we take a sample

from an unburnt area and we take apart the skin sample

and we seed the cells in a culture flask like this one.

We feed the cells with a special liquid, which is full of protein and sugar.

At some point, these cells will divide, will multiply.

And they will cover the entire bottom of the flask.

We remove the cells using a special chemical

and we take this sheet of cells into the surgery room

which means we can do the outer most layer of the skin,

which is very important, because without this layer you wouldn't be able to survive.

However, we cannot reconstruct sweat glands our hair follicles.

So these burnt patients have had their lives saved by stem cells,

but they have no hair and they don't sweat.

They are alive, but I can't say they have a normal life.

That's why many laboratories are trying to understand

how the skin is built to be able to reconstruct it in the lab,

so we can improve the life of these patients.

Stem cells are also used to treat patients with blood disorders,

A transplant of just a few blood stem cells,

is enough to repair the entire blood system.

Stem cells for specific tissues and organs

We know there are stem cells in skin, blood, guts and muscles,

but we don't know whether other organs have their own stem cells,

Back along the chain of development, there's another kind of stem cell.

It's controversial. It can become any specialised cell.

This cell comes from a blastocyst, the stage of development

For fertility treatment, blastocysts are produced in the laboratory.

If they are not used for a pregnancy, they can be donated for research.

In the early embryo, there's a group of cells

that can give rise to all the tissues of the body.

These are the cells we're very interested in