Why Do We All Have Snot?

Almost every type of living creature relies on mucus to help keep itself healthy. Learn what snot can teach us in this episode of BrainStuff, based on this article: https://health.howstuffworks.com/human-body/systems/respiratory/mucus.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff, a production of iHeartRadio. Hey brain stuff,
Lauren Bollebam here it's not. It is inherently gross. We
swallow loads of it every day, even on our healthiest
of days. And that slimy, gelatinous goo we call mucus

(00:22):
isn't just in our noses. It's actually found on all
of the wet surfaces of your body that aren't covered
in skin. That includes the lungs, sinuses, mouth, stomach, intestines, cervix,
and eyes, just to name a few. So why do
we have to put up with it? It turns out
that mucus plays a hugely important role in keeping us healthy,

(00:45):
and not just us humans, similar mucus helps protect pretty
much all other creatures as well. But mucus is a
bit of a mystery. Okay. We know that mucus is
made up almost entirely of water, along with tiny amounts
of hundreds of other compounds, including proteins, fats, and salts.
And we know that mammals, fish, amphibians, reptiles, birds, molluscs,

(01:10):
and some other invertebrates all produce mucus. But a study
from twenty twenty two found that many mucus related genes
don't share a common ancestor. This is relatively unusual because
genes with a similar function often evolve from a common
ancestral gene. But just in humans, genes that encode for

(01:32):
mucus are members of several families that probably evolved independently.
Further study, a team from the University of Buffalo looked
at the saliva of forty nine different species of mammals. Specifically,
they were looking at the musins in that saliva, musins
being the sort of key ingredient in mucus that makes

(01:53):
it slimy because musins tend to be good at forming
gels with water, and the research found that in some mammals,
new types of musins had evolved from other kinds of
non musin proteins, like fifteen independent times. The lead author
of the study, a University of Buffalo PhD student by

(02:15):
the name of Peter Pietz, said in a press release,
if these musins keep evolving from non musins over and
over again in different species at different times, it suggests
that there is some sort of adaptive pressure that makes
it beneficial. So it seems that evolution loves making slime certainly.

(02:37):
Mucus serves our bodies in lots of different ways, including
preventing tissues from drying out and cracking, which would expose
them to infection, lubricating the eyes, protecting the stomach lining
from acid, removing or trapping foreign substances, thus preventing them
from getting into the lungs or the bloodstream, and keeping
the bodies trillions of friendly bacterial inhabitants under control. Our

(03:02):
bodies are constantly producing mucus. In fact, the respiratory system
alone cranks out more than a liter of it every day,
and that's about forty fluid ounces. A lot of it
slides down the back of your throat, into your stomach
and eventually makes its way out of the body. When
you're healthy, you're probably not aware of all the mucus
rolling down the back of your throat unless you happen

(03:24):
to speak into microphones for a living. And thank you,
by the way, to Tyler and all of the other
fabulous producers here at iHeart for editing out my many,
many many throat clears in every episode. Anyway, when you're sick,
your mucus becomes thicker and stickier as your body ramps
up production of it in an attempt to flush out

(03:46):
the offending pathogens. And as we said above, humans aren't
the only creatures to produce mucus. Other animals do some
amazing things with it. Snails and slugs eat visco elastic
mucus that acts as both an adhesive and a lubricant,
enabling them to scoop seemingly effortlessly over rough terrain and

(04:09):
move vertically up it. All fish are covered in mucus,
but parrotfish also spit out little mucus sleeping bags that
they encase themselves in every night to protect them from parasites.
Some sea sponges sneeze to clear debris out of their pores,
similar to how you might blow your nose, but it

(04:30):
takes them between twenty and fifty minutes to complete one
sneeze like contraction and cave dwelling birds called swiftlets, use
their saliva to build gooey nests that stick to steep
cave walls. The nests are a delicacy in some Chinese cuisines,
in which the delicate cup shaped nests, which look a

(04:51):
little bit like a pastry shell when they're dried, are
boiled down to form a gelatinous soup called appropriately Birds'
Nest Soup. A snot still has a lot to teach us.
At the Massachusetts Institute of Technology, there's a lab run
by biological engineering professor Katharina Ribbeck that's dedicated to learning

(05:12):
how some pathogenic microbes have evolved to slip in through
our mucus barriers. Aribic told Statnews back in twenty eighteen
that mucus is the unsown hero that has been taming
problematic pathogens for millions of years. She and her team
want to figure out how to harness mucus to prevent
more infections, especially those caused by bacteria that are resistant

(05:35):
to antibiotics. Today's episode is based on the article the
Science Behind Why We All Have snot on how stuffworks
dot com, written by Jennifer Walker Journey Brainstuff is production
of by Heart Radio in partnership with how Stuffworks dot
Com and is produced by Tyler Klaying. For more podcasts
my heart Radio, visit the iHeartRadio app, Apple Podcasts, or

(05:57):
wherever you listen to your favorite shows.