WEBVTT - Why Do We All Have Snot? 0:00:01.840 --> 0:00:07.600 Welcome to brain Stuff, a production of iHeartRadio. Hey brain stuff, 0:00:07.680 --> 0:00:14.520 Lauren Bollebam here it's not. It is inherently gross. We 0:00:14.880 --> 0:00:17.960 swallow loads of it every day, even on our healthiest 0:00:18.000 --> 0:00:22.440 of days. And that slimy, gelatinous goo we call mucus 0:00:22.680 --> 0:00:25.960 isn't just in our noses. It's actually found on all 0:00:26.000 --> 0:00:28.360 of the wet surfaces of your body that aren't covered 0:00:28.400 --> 0:00:33.960 in skin. That includes the lungs, sinuses, mouth, stomach, intestines, cervix, 0:00:34.040 --> 0:00:38.559 and eyes, just to name a few. So why do 0:00:38.640 --> 0:00:41.280 we have to put up with it? It turns out 0:00:41.320 --> 0:00:45.240 that mucus plays a hugely important role in keeping us healthy, 0:00:45.720 --> 0:00:49.520 and not just us humans, similar mucus helps protect pretty 0:00:49.600 --> 0:00:55.120 much all other creatures as well. But mucus is a 0:00:55.160 --> 0:00:58.120 bit of a mystery. Okay. We know that mucus is 0:00:58.160 --> 0:01:01.320 made up almost entirely of water, along with tiny amounts 0:01:01.320 --> 0:01:05.120 of hundreds of other compounds, including proteins, fats, and salts. 0:01:05.680 --> 0:01:10.479 And we know that mammals, fish, amphibians, reptiles, birds, molluscs, 0:01:10.480 --> 0:01:15.240 and some other invertebrates all produce mucus. But a study 0:01:15.280 --> 0:01:18.920 from twenty twenty two found that many mucus related genes 0:01:19.200 --> 0:01:24.200 don't share a common ancestor. This is relatively unusual because 0:01:24.319 --> 0:01:27.679 genes with a similar function often evolve from a common 0:01:27.760 --> 0:01:32.120 ancestral gene. But just in humans, genes that encode for 0:01:32.280 --> 0:01:36.800 mucus are members of several families that probably evolved independently. 0:01:38.840 --> 0:01:41.920 Further study, a team from the University of Buffalo looked 0:01:41.920 --> 0:01:46.440 at the saliva of forty nine different species of mammals. Specifically, 0:01:46.680 --> 0:01:50.120 they were looking at the musins in that saliva, musins 0:01:50.200 --> 0:01:53.480 being the sort of key ingredient in mucus that makes 0:01:53.520 --> 0:01:56.680 it slimy because musins tend to be good at forming 0:01:56.800 --> 0:02:02.160 gels with water, and the research found that in some mammals, 0:02:02.440 --> 0:02:05.360 new types of musins had evolved from other kinds of 0:02:05.720 --> 0:02:13.200 non musin proteins, like fifteen independent times. The lead author 0:02:13.240 --> 0:02:15.920 of the study, a University of Buffalo PhD student by 0:02:15.919 --> 0:02:18.560 the name of Peter Pietz, said in a press release, 0:02:19.040 --> 0:02:22.480 if these musins keep evolving from non musins over and 0:02:22.520 --> 0:02:26.480 over again in different species at different times, it suggests 0:02:26.520 --> 0:02:29.400 that there is some sort of adaptive pressure that makes 0:02:29.400 --> 0:02:37.760 it beneficial. So it seems that evolution loves making slime certainly. 0:02:37.840 --> 0:02:41.079 Mucus serves our bodies in lots of different ways, including 0:02:41.200 --> 0:02:44.799 preventing tissues from drying out and cracking, which would expose 0:02:44.840 --> 0:02:49.000 them to infection, lubricating the eyes, protecting the stomach lining 0:02:49.000 --> 0:02:53.200 from acid, removing or trapping foreign substances, thus preventing them 0:02:53.200 --> 0:02:56.480 from getting into the lungs or the bloodstream, and keeping 0:02:56.520 --> 0:03:02.400 the bodies trillions of friendly bacterial inhabitants under control. Our 0:03:02.440 --> 0:03:07.120 bodies are constantly producing mucus. In fact, the respiratory system 0:03:07.160 --> 0:03:09.839 alone cranks out more than a liter of it every day, 0:03:10.000 --> 0:03:12.880 and that's about forty fluid ounces. A lot of it 0:03:12.919 --> 0:03:15.120 slides down the back of your throat, into your stomach 0:03:15.240 --> 0:03:18.760 and eventually makes its way out of the body. When 0:03:18.760 --> 0:03:21.520 you're healthy, you're probably not aware of all the mucus 0:03:21.680 --> 0:03:24.880 rolling down the back of your throat unless you happen 0:03:24.960 --> 0:03:27.720 to speak into microphones for a living. And thank you, 0:03:27.880 --> 0:03:30.239 by the way, to Tyler and all of the other 0:03:30.320 --> 0:03:33.480 fabulous producers here at iHeart for editing out my many, 0:03:33.840 --> 0:03:40.680 many many throat clears in every episode. Anyway, when you're sick, 0:03:40.760 --> 0:03:44.360 your mucus becomes thicker and stickier as your body ramps 0:03:44.400 --> 0:03:46.840 up production of it in an attempt to flush out 0:03:46.880 --> 0:03:52.520 the offending pathogens. And as we said above, humans aren't 0:03:52.560 --> 0:03:55.960 the only creatures to produce mucus. Other animals do some 0:03:56.080 --> 0:04:01.280 amazing things with it. Snails and slugs eat visco elastic 0:04:01.360 --> 0:04:04.680 mucus that acts as both an adhesive and a lubricant, 0:04:04.840 --> 0:04:08.800 enabling them to scoop seemingly effortlessly over rough terrain and 0:04:09.080 --> 0:04:14.200 move vertically up it. All fish are covered in mucus, 0:04:14.560 --> 0:04:18.840 but parrotfish also spit out little mucus sleeping bags that 0:04:18.880 --> 0:04:22.280 they encase themselves in every night to protect them from parasites. 0:04:23.920 --> 0:04:27.880 Some sea sponges sneeze to clear debris out of their pores, 0:04:28.160 --> 0:04:30.800 similar to how you might blow your nose, but it 0:04:30.880 --> 0:04:33.880 takes them between twenty and fifty minutes to complete one 0:04:34.120 --> 0:04:40.520 sneeze like contraction and cave dwelling birds called swiftlets, use 0:04:40.560 --> 0:04:44.040 their saliva to build gooey nests that stick to steep 0:04:44.120 --> 0:04:48.640 cave walls. The nests are a delicacy in some Chinese cuisines, 0:04:49.000 --> 0:04:51.840 in which the delicate cup shaped nests, which look a 0:04:51.880 --> 0:04:54.280 little bit like a pastry shell when they're dried, are 0:04:54.279 --> 0:04:58.240 boiled down to form a gelatinous soup called appropriately Birds' 0:04:58.279 --> 0:05:03.719 Nest Soup. A snot still has a lot to teach us. 0:05:04.160 --> 0:05:07.400 At the Massachusetts Institute of Technology, there's a lab run 0:05:07.440 --> 0:05:11.960 by biological engineering professor Katharina Ribbeck that's dedicated to learning 0:05:12.040 --> 0:05:15.800 how some pathogenic microbes have evolved to slip in through 0:05:15.800 --> 0:05:20.159 our mucus barriers. Aribic told Statnews back in twenty eighteen 0:05:20.320 --> 0:05:23.839 that mucus is the unsown hero that has been taming 0:05:23.920 --> 0:05:28.600 problematic pathogens for millions of years. She and her team 0:05:28.640 --> 0:05:31.120 want to figure out how to harness mucus to prevent 0:05:31.240 --> 0:05:35.040 more infections, especially those caused by bacteria that are resistant 0:05:35.080 --> 0:05:42.760 to antibiotics. Today's episode is based on the article the 0:05:42.800 --> 0:05:45.600 Science Behind Why We All Have snot on how stuffworks 0:05:45.640 --> 0:05:48.960 dot com, written by Jennifer Walker Journey Brainstuff is production 0:05:49.000 --> 0:05:51.160 of by Heart Radio in partnership with how Stuffworks dot 0:05:51.160 --> 0:05:54.279 Com and is produced by Tyler Klaying. For more podcasts 0:05:54.320 --> 0:05:57.520 my heart Radio, visit the iHeartRadio app, Apple Podcasts, or 0:05:57.560 --> 0:06:05.120 wherever you listen to your favorite shows.