Spit and Snot Operation Ouch!

Are you ready for our Ouch! Snips?

-Ouch!

-Exactly.

The answer is C - a litre.

Your body couldn't work without it.

And one form of mucus is your...

..snot. What is it? Where does it come from? And most importantly,

since it's so delicious, why has nobody started a snot restaurant?

Well, I've come to Cardiff University's

School of Biosciences to find out.

This is Dr Kelly Berube.

And she's a snot expert.

Kelly, what is snot?

Snot is a natural polymer that you create.

These are your cells

on all the mucus membranes that line all the areas of your body that

are exposed to the outside.

This isn't real snot, but it's a special mixture that Dr Kelly

has made to show exactly why it needs to be so sticky.

Anywhere where invaders - proteins, bacteria - can get in,

you need to have this material to keep them off.

See, you are sticking to it now, it's like flypaper.

So you inhale, boom - it sticks on there,

and then the defender cells will say,

"That shouldn't be in here," goes in and kills them.

Or you sneeze it, spit it or swallow it.

Just got to get it out of the body.

Mucus like this protects all the areas of your body

that are connected to the outside world.

So you make mucus in your nose, in your mouth,

all through your gut to your bum.

Also in your lungs and also covering your eyes.

Snot is actually nasal mucus.

These liquids show how your snot and mucus can be

lots of different colours.

So what can we tell about someone from looking at their mucus?

You can tell whether they are sick,

what kind of food they like to eat, what their occupation is

and even where they live.

What can you tell me about my body from looking at mine?

-We're going to have to pick some out. Are you game for that?

-Yeah.

So I'm taking a good sample of my snot on this sterile swab.

And now mucus from my lungs.

Sorry! But it is all in the name of medical research.

-So just a little bit yellow.

-Yeah.

-It's not bad but there are flecks of grey as well.

-Yeah.

So, it's time to get the results from all of my sticky mucus

and snot.

So what can you tell from looking at this?

If you look on the screen, the mucus is very thick and extended,

which has done what it's supposed to do,

like flypaper it's trapped things.

It's trapped a lot of soot particles.

Obviously, you live in a big city.

So it's done a great job, actually. It's done what it's supposed to do.

Looks like some pollen in there, actually, as well.

So the mucus in my body is doing exactly what it's supposed to do,

it's trapped all the things that could be causing me disease

and then I've been able to cough it up and get rid of it.

You also find mucus in your saliva.

Time to head to the lab to find out more.

As well as keeping your mouth fresh and healthy,

saliva has another very important job - it helps you eat and swallow.

It's 99% water, but there is a magic 1% containing mucus.

Which is what makes saliva slippery and slimy

and helps you swallow.

So to show you how amazing your mucusy saliva is...

..I bring you the Spit Slide Challenge.

Xander and I have a bowl each with some teeth to chew up

this plate of food.

We're going to chew up the food, put it in our mouths

and send it down the tube that goes from our mouths to our stomachs.

There is only one twist -

and that is, only one of us will have a bottle of saliva.

And that one is me.

-Me.

-Is me.

-It's me.

-No, me.

-It's me.

-I'm going to have it.

-That bloke looks just like you!

-Does he?

So he does!

-Let the chewing begin!

-What?! This isn't fair.

Get on with it.

Xand's adding some saliva to his bowl of chewed food,

exactly what happens in your mouth.

But I don't have any for mine!

Without saliva, chewing up my food is immensely difficult.

It's just formed a big solid mass in my mouth.

Thanks to saliva, my bowl of food is turning into a nice, slimy paste.

Time to get it down the hatch.

There you go!

Yes!

Look at how my food mixed with saliva slides down easily.

But check out Chris's.

Without saliva, my food gets stuck in the throat

instead of sliding to the stomach.

Chris, you've got to stop, he's choking!

He didn't even get to eat his tomatoes yet.

Well, you know what this means?

What? Chris is in danger?

No! That I'm the winner of the Spit Slide Challenge.

Thanks to saliva.

Thanks, saliva!

So we have shown you that mucus is vital in keeping your body

working, from your super-sticky snot to the

magic 1% mucus you find in your saliva.

-See you next time!

-Bye!

-Bye! Bye!

-Bye.

-Bye-ee!

-Bye.

-Bye-ee-ee!

THEY MOUTH