This Is How Your Skin Holds In Bodily Fluids

This Is How Your Skin Holds In Bodily Fluids


It might look like I’m leaking all the time
but I’m just crying. Hey freaky leakies, Jules here for Dnews. Our skin is an amazing organ. It’s a barrier for gross things that might
get into your body, it helps us sense the world around us, it keeps us from overheating
and overcooling, it even synthesizes Vitamin D when UV rays hit it. But perhaps one of the most impressive things
about it, to me at least, is that your skin holds all your blood and guts and mucous,
and other fluids and gasses without leaking. Sure, we do stuff like sweat, but that’s
a controlled response, often to heat, and it’s only sweat that comes out. On top of all that, we shed millions, and
by some accounts, billions of skin cells every single day, and yet somehow everything important
stays inside. We take this for granted, but we shouldn’t! Because the way it is able to form a tight
seal is absolutely incredible, and only recently discovered. But first, let’s get the skinny on skin. Human skin is made up of several layers of
tissue, but it’s the top one, [points at hand] this one, that makes us effectively
leakproof. It’s called the epidermis, and it is actually
made up of its own series of distinct layers. Yes, it’s layers within layers, it’s skinception. The outermost layer of the epidermis is the
one that is constantly shedding off, millions of times a day, it is called the stratum corneum. That’s Latin for “horny layer”. Beneath that is a layer called the stratum
granulosum, and that’s where the no-leak magic happens. New research from 2016, published in the journal
eLife looked at skin cells in mice using highly specialized light-based microscopes, cross
referenced against mathematical models, to determine that the key to the skin’s tight
seal is actually it’s shape. This stratum granulosum is arranged like a
checkerboard pattern, except instead of 2 dimensional squares it’s flattened versions
of 3 dimensional tetrakaidecahedron. That means they have 14 sides, with six rectangular,
and eight hexagonal. They’re actually called “Kelvin’s tetrakaidecahedron”,
after Lord Kelvin, an 19th century mathematician who dared to ask “hey how do we make stuff
fit together with no gaps and minimal surface area?” Turns out, all he needed was a two-photon
microscope to get the answer. Too bad those were invented 100 years later. These Kelvin shapes are arranged in a sort
of zipper-like honeycomb pattern. And not only are there effectively no gaps
in this arrangement, but the cells in that region are also capable of producing a sort
of glue, that binds this shape together, so this perfect fit doesn’t fall apart. What is perhaps most amazing about this whole
arrangement, is that it’s configuration lets the old skin cells at the top disengage,
while keeping a redundant seal beneath them, then pushing the new skin cells forward with
another seal behind that. Like a tightly bound conveyor belt pushing
old skin out and new skin up, never breaking the seal. So the next time you’re sitting around in
one piece, with all your blood and guts and stuff securely inside of your body, take a
second and be grateful that you don’t need to wear a scuba suit all the time. So your skin doesn’t leak but did you know
that it also can’t tear? That’s kind of amazing and you can find out
why in this video right here. And do you have any other questions about
skin in general? Let us know down below in the comments and
don’t forget to like and subscribe for more DNews everyday.

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