0:00:02 > 0:00:03Are you ready for our Ouch! Snips?
0:00:03 > 0:00:04- Ouch!- Exactly.
0:00:17 > 0:00:19The answer is C - a litre.
0:00:19 > 0:00:21Your body couldn't work without it.
0:00:21 > 0:00:23And one form of mucus is your...
0:00:23 > 0:00:27..snot. What is it? Where does it come from? And most importantly,
0:00:27 > 0:00:31since it's so delicious, why has nobody started a snot restaurant?
0:00:31 > 0:00:33Well, I've come to Cardiff University's
0:00:33 > 0:00:35School of Biosciences to find out.
0:00:35 > 0:00:37This is Dr Kelly Berube.
0:00:37 > 0:00:39And she's a snot expert.
0:00:39 > 0:00:40Kelly, what is snot?
0:00:40 > 0:00:43Snot is a natural polymer that you create.
0:00:43 > 0:00:45These are your cells
0:00:45 > 0:00:48on all the mucus membranes that line all the areas of your body that
0:00:48 > 0:00:49are exposed to the outside.
0:00:49 > 0:00:53This isn't real snot, but it's a special mixture that Dr Kelly
0:00:53 > 0:00:57has made to show exactly why it needs to be so sticky.
0:00:57 > 0:00:59Anywhere where invaders - proteins, bacteria - can get in,
0:00:59 > 0:01:01you need to have this material to keep them off.
0:01:01 > 0:01:04See, you are sticking to it now, it's like flypaper.
0:01:04 > 0:01:06So you inhale, boom - it sticks on there,
0:01:06 > 0:01:07and then the defender cells will say,
0:01:07 > 0:01:10"That shouldn't be in here," goes in and kills them.
0:01:10 > 0:01:11Or you sneeze it, spit it or swallow it.
0:01:11 > 0:01:13Just got to get it out of the body.
0:01:13 > 0:01:15Mucus like this protects all the areas of your body
0:01:15 > 0:01:17that are connected to the outside world.
0:01:17 > 0:01:19So you make mucus in your nose, in your mouth,
0:01:19 > 0:01:21all through your gut to your bum.
0:01:21 > 0:01:24Also in your lungs and also covering your eyes.
0:01:24 > 0:01:27Snot is actually nasal mucus.
0:01:27 > 0:01:29These liquids show how your snot and mucus can be
0:01:29 > 0:01:31lots of different colours.
0:01:31 > 0:01:34So what can we tell about someone from looking at their mucus?
0:01:34 > 0:01:36You can tell whether they are sick,
0:01:36 > 0:01:39what kind of food they like to eat, what their occupation is
0:01:39 > 0:01:41and even where they live.
0:01:41 > 0:01:43What can you tell me about my body from looking at mine?
0:01:43 > 0:01:46- We're going to have to pick some out. Are you game for that?- Yeah.
0:01:46 > 0:01:49So I'm taking a good sample of my snot on this sterile swab.
0:01:51 > 0:01:52And now mucus from my lungs.
0:01:54 > 0:01:56Sorry! But it is all in the name of medical research.
0:01:56 > 0:01:58- So just a little bit yellow. - Yeah.
0:01:58 > 0:02:00- It's not bad but there are flecks of grey as well.- Yeah.
0:02:02 > 0:02:05So, it's time to get the results from all of my sticky mucus
0:02:05 > 0:02:07and snot.
0:02:07 > 0:02:08So what can you tell from looking at this?
0:02:08 > 0:02:11If you look on the screen, the mucus is very thick and extended,
0:02:11 > 0:02:13which has done what it's supposed to do,
0:02:13 > 0:02:14like flypaper it's trapped things.
0:02:14 > 0:02:16It's trapped a lot of soot particles.
0:02:16 > 0:02:18Obviously, you live in a big city.
0:02:18 > 0:02:21So it's done a great job, actually. It's done what it's supposed to do.
0:02:21 > 0:02:23Looks like some pollen in there, actually, as well.
0:02:23 > 0:02:26So the mucus in my body is doing exactly what it's supposed to do,
0:02:26 > 0:02:28it's trapped all the things that could be causing me disease
0:02:28 > 0:02:31and then I've been able to cough it up and get rid of it.
0:02:31 > 0:02:33You also find mucus in your saliva.
0:02:33 > 0:02:36Time to head to the lab to find out more.
0:02:36 > 0:02:38As well as keeping your mouth fresh and healthy,
0:02:38 > 0:02:44saliva has another very important job - it helps you eat and swallow.
0:02:44 > 0:02:49It's 99% water, but there is a magic 1% containing mucus.
0:02:49 > 0:02:52Which is what makes saliva slippery and slimy
0:02:52 > 0:02:54and helps you swallow.
0:02:54 > 0:02:58So to show you how amazing your mucusy saliva is...
0:02:58 > 0:03:01..I bring you the Spit Slide Challenge.
0:03:04 > 0:03:08Xander and I have a bowl each with some teeth to chew up
0:03:08 > 0:03:10this plate of food.
0:03:10 > 0:03:12We're going to chew up the food, put it in our mouths
0:03:12 > 0:03:16and send it down the tube that goes from our mouths to our stomachs.
0:03:16 > 0:03:17There is only one twist -
0:03:17 > 0:03:20and that is, only one of us will have a bottle of saliva.
0:03:20 > 0:03:21And that one is me.
0:03:21 > 0:03:23- Me.- Is me. - It's me.- No, me.- It's me.
0:03:23 > 0:03:27- I'm going to have it.- That bloke looks just like you!- Does he?
0:03:27 > 0:03:28So he does!
0:03:28 > 0:03:31- Let the chewing begin! - What?! This isn't fair.
0:03:31 > 0:03:32Get on with it.
0:03:34 > 0:03:38Xand's adding some saliva to his bowl of chewed food,
0:03:38 > 0:03:40exactly what happens in your mouth.
0:03:40 > 0:03:42But I don't have any for mine!
0:03:42 > 0:03:45Without saliva, chewing up my food is immensely difficult.
0:03:45 > 0:03:48It's just formed a big solid mass in my mouth.
0:03:48 > 0:03:53Thanks to saliva, my bowl of food is turning into a nice, slimy paste.
0:03:54 > 0:03:55Time to get it down the hatch.
0:03:59 > 0:04:00There you go!
0:04:03 > 0:04:04Yes!
0:04:04 > 0:04:08Look at how my food mixed with saliva slides down easily.
0:04:08 > 0:04:10But check out Chris's.
0:04:10 > 0:04:12Without saliva, my food gets stuck in the throat
0:04:12 > 0:04:14instead of sliding to the stomach.
0:04:14 > 0:04:18Chris, you've got to stop, he's choking!
0:04:18 > 0:04:20He didn't even get to eat his tomatoes yet.
0:04:20 > 0:04:22Well, you know what this means?
0:04:22 > 0:04:23What? Chris is in danger?
0:04:23 > 0:04:26No! That I'm the winner of the Spit Slide Challenge.
0:04:26 > 0:04:28Thanks to saliva.
0:04:28 > 0:04:29Thanks, saliva!
0:04:29 > 0:04:33So we have shown you that mucus is vital in keeping your body
0:04:33 > 0:04:36working, from your super-sticky snot to the
0:04:36 > 0:04:39magic 1% mucus you find in your saliva.
0:04:39 > 0:04:42- See you next time!- Bye!- Bye! Bye!- Bye.
0:04:42 > 0:04:46- Bye-ee!- Bye.- Bye-ee-ee!
0:04:47 > 0:04:48THEY MOUTH