(stoic, classical orchestral music)
(chalk scraping)
(chalk squeaks)
- Hi I'm Lauren and this is Brain Stuff.
(digital swish)
If you thought the ink
in your home printer
was getting expensive
imagine how much a cartridge
would cost for a machine
that can print human tissue.
Yeah, that's a thing.
If you're watching this right now
chances are pretty high
that you have skin.
It's a human being's largest organ
and if you stretched out
the skin of an average adult
it would cover 22 square feet.
That's about two square meters.
That could make a lot of
serial killer couture.
But if we're getting into the business
of actually making
tissue let's take a look
at what skin is made of before we start
printing it in our garage.
The top of skin Is actually several layers
of tightly packed cells
called the epidermis.
It's top layer is called
the stratum corneum,
which is filled with white blood cells
and protects us against
infections and diseases.
The epidermis also contains melanocytes
that make up the pigment or melanin
that gives skin its color.
But you know what the weirdest thing
about the epidermis is?
It's mostly composed off dead skin cells
that we're constantly
shedding all over the place.
In fact it takes around 35 days for humans
to fully shed our skin.
Under the epidermis is,
well the dermis.
(digital pop)
This is where your blood
vessels are located
so if you're bleeding from a cut
your dermis is exposed.
And you'll know it
because this is also where
your nerve endings send
signals to your brain,
like heat, cold, pressure and yeah, pain.
The dermis is also full of collagen
which gives your skin
it's firm durability.
Uh yup, that's the same stuff that people
inject into their lips
to make them permanently
full and swollen, except that collagen
usually comes from cow hide.
(cow brays)
Yay.
And collagen isn't even the grossest thing
in the dermis, that award goes to
an oily skin lubricant called sebum
that's secreted out of
the sebaceous glands.
Sebum regulates body heat,
waterproofs your skin
and protects it from bacterial
and fungal infections,
plus gives you pimples.
Okay, so the deepest layer of
skin is called the hypodermis.
It's basically a subcutaneous tissue
that connects our skin
to our bones and muscles.
It's composed of fat
cells that keep us warm
and pad our innards from blunt injuries.
So, let's go back to the part where I said
your skin will heal over.
What this means is that the proteins
in your blood like fibrin work together
with blood platelets and plasma to form
what we call a scab.
Under this disgusting protective layer
your skin starts to regenerate,
like Wolverine, but way slower.
Scars happen when a skin wound is so deep
that it cuts into the dermis layer.
And scars aren't like normal skin tissue.
They don't have hair or sweat glands
and they're more vulnerable
to ultraviolet rays.
So okay.
As cool as scars are let's say
we don't want them anymore.
Can we make skin to replace
what's been damaged?
The answer is not just yet.
At least not seamlessly.
However under certain conditions
stem cells can be induced
to become skin tissue.
And the more we learn about stem cells
the better we get at
replacing damaged cells
with healthy ones.
So how about it?
What kind of scars do you
fracking skin jobs have?
I mostly have mental ones.
But if you have any physical ones
which one would you first want to print
some human issue to cover up?
Let us know on Facebook or Twitter.
And hey, check us out
at brainstuffshow.com.
