Speaker 1: Welcome to brain Stuff from How Stuff Works. Hi, brain
Speaker 1: Stuff listeners. I'm Lauren voc Obam, and today's episode is
Speaker 1: another brain Stuff classic from our former host, Christian Sagar.
Speaker 1: We're delving into perhaps the most important biological question known
Speaker 1: to humankind. What are eyeboggers? A brain stuff Christian Sager Here,
Speaker 1: Today's question is what our eyeboggers. If you've ever had
Speaker 1: to wipe gunk out of the corner of your eyes,
Speaker 1: it's not because you were visited by the Sandman or
Speaker 1: a magical mucus ferry. Nope, we live in a cruelly
Speaker 1: mundane universe, and I'm sorry if I'm the first to
Speaker 1: break it to you, but eyeboggers are a build up
Speaker 1: of the pre corneal or basil tier film that coats
Speaker 1: and protects your eyes, plus any foreign particles it catches.
Speaker 1: This tier film is just three micrometers thick, which is
Speaker 1: less than half the diameter of a red blood cell.
Speaker 1: But it's made up of three components, the mucin, the aqueous,
Speaker 1: and the lipid. These are indistinct layers of stuff that
Speaker 1: your body produces. The aqueous component is the operative one.
Speaker 1: It nourishes, lubricates, and flushes your eyes cells. It also
Speaker 1: smooths over microscopic lumps and bumps on the surface of
Speaker 1: your eyes, creating a smooth lens that optimizes light transfer
Speaker 1: into your retina. The other two components are a support
Speaker 1: system for the aqueous one. The musing component underneath it
Speaker 1: allows it to temporarily stick to your eye, and the
Speaker 1: lipid component outside it holds it in place so that
Speaker 1: you're not just you know, crying constantly. So closest to
Speaker 1: your corneal surface cells, you've got the musing component of
Speaker 1: the tear film. Mucins are the proteins that make mucus slimy.
Speaker 1: They're important in your eyes because corneal cells. Your corneal
Speaker 1: cells need water and water soluble new reents, but your
Speaker 1: corneal cells, unhelpfully are hydrophobic, meaning they repel water like
Speaker 1: microscopic little ducks. Mucin helps out by latching onto your
Speaker 1: corneal cells, specifically via adhesive molecules called glycocalyx that grow
Speaker 1: on the cell's surface, and mucans are hydrophilic, meaning that
Speaker 1: they grab onto water molecules. Next up the aqueous component.
Speaker 1: As you may have guessed from the name, this layer
Speaker 1: is made up of about water plus two percent water
Speaker 1: soluble stuff at any given time. Part of that two
Speaker 1: percent is things your corneal cells need, like electrolytes, oxygen,
Speaker 1: and antibacterial enzymes, and part is the cell's waste. There
Speaker 1: are also some musans floating around in there, and usually
Speaker 1: some dust debris, and you know sun dream microbes. Finally,
Speaker 1: topping it all off, you've got the lipid component a
Speaker 1: k a. The me bum. It's made mostly of wax
Speaker 1: and cholesterol esters. These esters are slick, hydrophobic substances that
Speaker 1: our bodies used to lubricate and waterproof various tissues in
Speaker 1: the tear film. They float on top of the aqueous layer,
Speaker 1: helping our eyelids glide easily over our eyes. They also
Speaker 1: provide a strong surface tension for our basil tears. Without
Speaker 1: the lipid layer, our tear film would drip right off
Speaker 1: our eyeballs. But how do these components become eyeboggers and
Speaker 1: why do they accumulate in the inner corners of your eyes. Well,
Speaker 1: I'm gonna tell you. When you blink, your entire eyelid
Speaker 1: doesn't close simultaneously. It shuts like a clapboard from the
Speaker 1: outer corners of your eyes inward towards your nose, your
Speaker 1: tear film gets pushed along by that motion. Upon reaching
Speaker 1: the inner corner of your eye, most of the film
Speaker 1: drains out through the tear ducts, which empty into your
Speaker 1: nasal cavity, and some of the film, the mucin and
Speaker 1: oils and debris, can clump together and get stuck. When
Speaker 1: enough of that builds up, it forms the goop known
Speaker 1: as eyeboggers, and when it accumulates and dries overnight because
Speaker 1: you're not blinking it away, it forms the crusty gunk
Speaker 1: known as sleep or SAM. Today's episode was produced by
Speaker 1: Tyler Clang and written by me for brainstuffs YouTube series
Speaker 1: in the Way Back. If you like our show and
Speaker 1: also like not being naked, check out our merch store
Speaker 1: at t public dot com slash brainstuff, and of course,
Speaker 1: for more on this and lots of other gross but
Speaker 1: fascinating topics, visit our home planet, how Stuff Works dot
Speaker 1: com