1 00:00:01,840 --> 00:00:07,920 Speaker 1: Welcome to Brainstuff, a production of iHeartRadio. Hey Brainstuff. Lauren 2 00:00:07,960 --> 00:00:13,080 Speaker 1: Bobelbam here. If you've ever watched a medieval era drama 3 00:00:13,320 --> 00:00:17,160 Speaker 1: or fantasy, you may have marveled at the elaborate armor 4 00:00:17,239 --> 00:00:22,000 Speaker 1: that characters wear into battle. Made of plates or scales 5 00:00:22,120 --> 00:00:25,640 Speaker 1: or mail, armor is built to protect the wearer from 6 00:00:25,760 --> 00:00:30,480 Speaker 1: specific types of weapons and attacks. It may not feel 7 00:00:30,520 --> 00:00:33,279 Speaker 1: like it, but your skin is also a type of 8 00:00:33,320 --> 00:00:38,600 Speaker 1: incredibly effective armor built to fend off specific attacks. It's 9 00:00:38,680 --> 00:00:41,960 Speaker 1: not great at handling swords or arrows, but to be fair, 10 00:00:42,200 --> 00:00:47,920 Speaker 1: those are relatively new inventions, far older threats like microbes 11 00:00:47,960 --> 00:00:51,720 Speaker 1: and ultraviolet light. That's where our skin is a hero. 12 00:00:53,120 --> 00:00:55,319 Speaker 1: It's our first line of defense as we move through 13 00:00:55,320 --> 00:00:58,840 Speaker 1: the world, though it operates more like the manned walls 14 00:00:58,840 --> 00:01:03,520 Speaker 1: of a castle than armor on a knight. Specialized cells 15 00:01:03,560 --> 00:01:07,840 Speaker 1: and surrounding structures form a physical barrier between you and 16 00:01:08,200 --> 00:01:11,280 Speaker 1: everything that's not you, sort of like a castle wall, 17 00:01:11,880 --> 00:01:15,160 Speaker 1: and inside of that, an immune barrier stands at the 18 00:01:15,240 --> 00:01:18,600 Speaker 1: ready like a castle's guard, to eliminate any threats that 19 00:01:18,680 --> 00:01:23,440 Speaker 1: do make it through. But for our body's most visible organ. 20 00:01:24,000 --> 00:01:28,160 Speaker 1: All of this happens on a microscopic level. So today 21 00:01:28,440 --> 00:01:31,399 Speaker 1: let's delve into the skin barrier, how it protects us, 22 00:01:31,640 --> 00:01:35,840 Speaker 1: and what can happen when something goes wrong. We've talked 23 00:01:35,840 --> 00:01:38,080 Speaker 1: before on the show about the layers of the skin. 24 00:01:38,760 --> 00:01:43,200 Speaker 1: The innermost layer, the hypodermis, provides structural support. It contains 25 00:01:43,280 --> 00:01:46,800 Speaker 1: fat to insulate and cushion our underlying muscles and organs, 26 00:01:46,920 --> 00:01:49,720 Speaker 1: plus blood vessels to get supplies to the middle layer, 27 00:01:49,880 --> 00:01:53,400 Speaker 1: the dermis. The dermis contains all of the skin's equipment, 28 00:01:53,880 --> 00:01:57,880 Speaker 1: nerve endings, sweat glands, pair follicles, and so on. All 29 00:01:57,920 --> 00:02:01,200 Speaker 1: of that is sealed in and protected the outermost layer, 30 00:02:01,440 --> 00:02:06,120 Speaker 1: the epidermis. The epidermis itself has two main layers, the 31 00:02:06,160 --> 00:02:08,680 Speaker 1: inner of which is living, and the outer of which 32 00:02:08,800 --> 00:02:12,320 Speaker 1: is dead. The dead skin cells of the outer layer 33 00:02:12,400 --> 00:02:15,280 Speaker 1: are what we see and touch, and it's called the 34 00:02:15,320 --> 00:02:20,040 Speaker 1: stratum cornium. The stratum corneum is often described as being 35 00:02:20,160 --> 00:02:23,240 Speaker 1: like a brick wall, though luckily for us, a very 36 00:02:23,280 --> 00:02:26,880 Speaker 1: flexible one, because it's made up of tough cells that 37 00:02:26,960 --> 00:02:30,079 Speaker 1: are stacked and bound together with a kind of mortar 38 00:02:30,560 --> 00:02:36,440 Speaker 1: of waxy, fatty lipids and some adhesive proteins. Those tough 39 00:02:36,480 --> 00:02:41,440 Speaker 1: cells are called corneocytes. It's weird to think that their 40 00:02:41,639 --> 00:02:45,120 Speaker 1: entire purpose in life is to die, but it's for 41 00:02:45,160 --> 00:02:48,399 Speaker 1: the greater good of the organism. Because they're dead, they 42 00:02:48,480 --> 00:02:51,560 Speaker 1: can't be infected by a virus or stopped from doing 43 00:02:51,639 --> 00:02:55,040 Speaker 1: their job by bacteria. At their job is to sit there. 44 00:02:56,240 --> 00:02:58,799 Speaker 1: They develop in the inner part of the epidermis, and 45 00:02:58,840 --> 00:03:01,360 Speaker 1: as they're pushed to the out side, they die and 46 00:03:01,560 --> 00:03:07,480 Speaker 1: flatten into sort of long, hardened envelopes containing keratin. Keratin 47 00:03:07,600 --> 00:03:10,200 Speaker 1: is the protein that makes our hair and nails tough, 48 00:03:10,680 --> 00:03:14,960 Speaker 1: and other things too, like feathers, hoofs, and horns. The 49 00:03:15,000 --> 00:03:19,200 Speaker 1: etymology of the words keratin and corneocyte is actually related 50 00:03:19,280 --> 00:03:22,120 Speaker 1: to the word horn. They all root back to early 51 00:03:22,200 --> 00:03:25,440 Speaker 1: Indo European words for the hard and bony things that 52 00:03:25,480 --> 00:03:28,760 Speaker 1: come off of an animal's skull. It's the same root 53 00:03:28,760 --> 00:03:33,480 Speaker 1: where we get the word for the horn shaped cornucopia. Anyway, 54 00:03:34,320 --> 00:03:38,560 Speaker 1: the tough corneocytes in your stratum corneum also contains stuff 55 00:03:38,600 --> 00:03:41,920 Speaker 1: that can grab up molecules of water, which is good 56 00:03:42,040 --> 00:03:45,680 Speaker 1: because ideally your outer skin should be dry. No one 57 00:03:45,760 --> 00:03:50,720 Speaker 1: wants permanently moist skin, but not too dry. Having a 58 00:03:50,760 --> 00:03:53,400 Speaker 1: bit of water in your skin keeps it pliable and 59 00:03:53,480 --> 00:03:57,920 Speaker 1: prevents the skin from cracking. And as I said, the 60 00:03:58,000 --> 00:04:01,200 Speaker 1: corneocytes are bound together with the sort of mortar made 61 00:04:01,240 --> 00:04:04,400 Speaker 1: up of sticky proteins and a bunch of lipids, which 62 00:04:04,440 --> 00:04:09,320 Speaker 1: are fatty or waxy substances. This is great because a 63 00:04:09,520 --> 00:04:13,160 Speaker 1: it holds the corneosytes tightly in place, and also b 64 00:04:13,840 --> 00:04:18,240 Speaker 1: it's what makes our skin more or less waterproof. Oil 65 00:04:18,240 --> 00:04:21,479 Speaker 1: and water repel each other, so the oily lipids help 66 00:04:21,560 --> 00:04:25,719 Speaker 1: make our skin impermeable to water. The stratum cornium is 67 00:04:25,920 --> 00:04:28,880 Speaker 1: essentially the reason that all of the water that makes 68 00:04:28,960 --> 00:04:31,360 Speaker 1: up some sixty percent of our body and makes our 69 00:04:31,480 --> 00:04:36,200 Speaker 1: organs work stays in our body and doesn't just evaporate out. 70 00:04:36,880 --> 00:04:41,040 Speaker 1: It also prevents many potentially harmful water based liquids, including 71 00:04:41,080 --> 00:04:45,440 Speaker 1: ones that contain germs, from leaking into our body. Not 72 00:04:45,600 --> 00:04:48,160 Speaker 1: too shabby for a stack of dead cells only some 73 00:04:48,279 --> 00:04:51,599 Speaker 1: ten to twenty micrometers thick, which is about the thickness 74 00:04:51,640 --> 00:04:54,960 Speaker 1: of one or two layers of plastic wrap. Even the 75 00:04:55,040 --> 00:04:58,080 Speaker 1: fact that the corneocytes are dead and thus can't be 76 00:04:58,200 --> 00:05:01,760 Speaker 1: repaired when they wear out and therefore get sloughed off 77 00:05:01,760 --> 00:05:05,320 Speaker 1: and replaced on a continual basis. That's a feature, not 78 00:05:05,400 --> 00:05:09,080 Speaker 1: a bug. This way, any microbes that might take up 79 00:05:09,120 --> 00:05:12,599 Speaker 1: residents in or around your corneocytes get slothed right off 80 00:05:12,640 --> 00:05:17,200 Speaker 1: with them. In healthy skin, your stratum cornium totally replaces 81 00:05:17,240 --> 00:05:21,279 Speaker 1: itself about once a month. The cells in the layer 82 00:05:21,400 --> 00:05:24,800 Speaker 1: of the epidermis directly beneath the stratum cornium where the 83 00:05:24,800 --> 00:05:29,520 Speaker 1: corneocytes develop, are also tightly junctured together, adding to the 84 00:05:29,600 --> 00:05:33,720 Speaker 1: security of the physical barrier of our skin. Plus they 85 00:05:33,760 --> 00:05:40,240 Speaker 1: release some helpfully antimicrobial molecules. Because as impressive as this 86 00:05:40,360 --> 00:05:44,279 Speaker 1: physical barrier is, it is then and delicate and pretty 87 00:05:44,279 --> 00:05:48,800 Speaker 1: easily scratched or pierced. That's why we have an immune 88 00:05:48,920 --> 00:05:52,799 Speaker 1: border guard lying in wait just inside our skin's castle wall. 89 00:05:53,960 --> 00:05:56,839 Speaker 1: Our immune system is really complicated, and I am not 90 00:05:57,040 --> 00:06:00,400 Speaker 1: a medical professional, y'all, I was an English major. But 91 00:06:00,720 --> 00:06:05,520 Speaker 1: very basically, your epidermis and dermis each contain some specialized 92 00:06:05,560 --> 00:06:10,800 Speaker 1: immune cells that can contain and neutralize any invaders. They 93 00:06:10,800 --> 00:06:13,800 Speaker 1: can also call in backup from other immune cells that 94 00:06:13,880 --> 00:06:18,040 Speaker 1: exist throughout the body via chemical signaling that creates inflammation. 95 00:06:19,480 --> 00:06:21,200 Speaker 1: If you think about the last time you got a 96 00:06:21,279 --> 00:06:23,880 Speaker 1: scrape or a cut, you may have noticed that it 97 00:06:23,960 --> 00:06:28,040 Speaker 1: got reddish or purplish and puffed up a bit. That 98 00:06:28,120 --> 00:06:31,640 Speaker 1: inflammation may be uncomfortable, but it's our body's way of 99 00:06:31,720 --> 00:06:34,560 Speaker 1: getting extra supplies to the site of an injury to 100 00:06:34,720 --> 00:06:39,799 Speaker 1: prevent infection and heal everything up. Once that backup arrives 101 00:06:39,839 --> 00:06:42,560 Speaker 1: to the site, all of the immune cells work together 102 00:06:42,640 --> 00:06:46,560 Speaker 1: inside the skin to clear out invaders and cellular debris. 103 00:06:47,600 --> 00:06:50,920 Speaker 1: When they're done, other cells call off the inflammation and 104 00:06:51,120 --> 00:06:54,840 Speaker 1: everything goes back to normal. The physical barrier is restored, 105 00:06:55,120 --> 00:06:57,960 Speaker 1: and the immune barrier steps down from red alert to 106 00:06:58,080 --> 00:07:03,680 Speaker 1: a state of watchful preparedness. Of course, this is assuming 107 00:07:03,720 --> 00:07:08,279 Speaker 1: that everything is operating normally. The creation of the physical 108 00:07:08,320 --> 00:07:11,840 Speaker 1: barrier and the responses of the immune barrier are both 109 00:07:11,920 --> 00:07:17,120 Speaker 1: extremely complex processes, and unfortunately, any number of things can 110 00:07:17,200 --> 00:07:20,840 Speaker 1: upset them, either from the outside in or the inside out, 111 00:07:21,480 --> 00:07:27,080 Speaker 1: or both. Just for example, that lipid mortar around corneocytes 112 00:07:27,320 --> 00:07:30,640 Speaker 1: gets produced by the corneocytes themselves as they develop into 113 00:07:30,640 --> 00:07:34,560 Speaker 1: their final form. So if anything changes in the cells 114 00:07:34,600 --> 00:07:39,200 Speaker 1: developmental process, say if it moves too fast, that doesn't 115 00:07:39,240 --> 00:07:42,800 Speaker 1: just disrupt how those corneocyte bricks stack up. It can 116 00:07:42,840 --> 00:07:46,280 Speaker 1: also disrupt the formation of the mortar around them, and 117 00:07:46,440 --> 00:07:49,680 Speaker 1: having too much or too little of any component in 118 00:07:49,720 --> 00:07:52,800 Speaker 1: the bricks or the mortar changes the way that the 119 00:07:52,840 --> 00:07:58,280 Speaker 1: wall holds together. From the outside, our skin can become 120 00:07:58,360 --> 00:08:01,080 Speaker 1: brittle if our environment is too dry, but it can 121 00:08:01,080 --> 00:08:05,360 Speaker 1: also get flaky if it's too humid. Exposure to irritating 122 00:08:05,480 --> 00:08:10,720 Speaker 1: or allergenic substances can cause an overactive immune response. Getting 123 00:08:10,760 --> 00:08:13,520 Speaker 1: too much sun does cellular damage that your skin has 124 00:08:13,560 --> 00:08:17,840 Speaker 1: to repair, which when repeated, will reduce cellular function over time. 125 00:08:18,920 --> 00:08:21,840 Speaker 1: Even our mental health and stress levels are tied into 126 00:08:21,880 --> 00:08:25,960 Speaker 1: how our organs function, and our skin certainly is an exempt, 127 00:08:26,120 --> 00:08:28,360 Speaker 1: as anyone who's ever gotten a ZiT before a big 128 00:08:28,400 --> 00:08:32,080 Speaker 1: event can tell you. From the inside, there are a 129 00:08:32,200 --> 00:08:35,680 Speaker 1: number of diseases and conditions that muck about with some 130 00:08:35,840 --> 00:08:40,559 Speaker 1: part of the skin barrier's upkeep, resulting in itchiness, flakiness, 131 00:08:40,679 --> 00:08:45,480 Speaker 1: or other discomfort at best. For example, we talked recently 132 00:08:45,520 --> 00:08:48,320 Speaker 1: on the show about psoriasis, a condition in which a 133 00:08:48,360 --> 00:08:52,080 Speaker 1: combination of skin cell overgrowth and immune system freak out 134 00:08:52,400 --> 00:08:56,439 Speaker 1: creates uncomfortable, scaly, or discolored patches that come and go, 135 00:08:56,920 --> 00:09:01,120 Speaker 1: triggered by those outside stressors that I mentioned. If you 136 00:09:01,240 --> 00:09:05,400 Speaker 1: or someone in your care experiences chronic skin barrier disruptions 137 00:09:05,400 --> 00:09:08,440 Speaker 1: that result in that kind of issue. Definitely talk to 138 00:09:08,440 --> 00:09:11,920 Speaker 1: a medical professional about the best way or ways to proceed. 139 00:09:12,720 --> 00:09:15,400 Speaker 1: There are lots of topical and systemic treatments that can 140 00:09:15,440 --> 00:09:18,280 Speaker 1: help control activity in the immune system or the skin, 141 00:09:18,760 --> 00:09:20,599 Speaker 1: and a healthcare provider will be able to help you 142 00:09:20,640 --> 00:09:24,920 Speaker 1: with the diagnosis and a plan. That being said, even 143 00:09:25,000 --> 00:09:28,520 Speaker 1: finding a regimen that keeps quote unquote normal skin happy 144 00:09:28,720 --> 00:09:31,840 Speaker 1: can be a challenge because the skin barrier is so 145 00:09:32,000 --> 00:09:35,559 Speaker 1: complex that its exact functions are really pretty unique to 146 00:09:35,600 --> 00:09:40,040 Speaker 1: all of us, and it changes over time. Simply getting 147 00:09:40,040 --> 00:09:43,400 Speaker 1: older means that our skin structure thins and becomes less 148 00:09:43,400 --> 00:09:47,400 Speaker 1: elastic and develops a different balance of immune cells. These 149 00:09:47,520 --> 00:09:51,000 Speaker 1: changes in our skin barrier make us more susceptible to infections. 150 00:09:52,240 --> 00:09:55,960 Speaker 1: A specialist like a dermatologist or esthetician may be able 151 00:09:56,000 --> 00:09:59,200 Speaker 1: to help find exactly the right kind of moisturizer and 152 00:09:59,360 --> 00:10:03,880 Speaker 1: other products for you, but the top level advice is 153 00:10:03,920 --> 00:10:06,760 Speaker 1: to prevent skin barrier damage in the first place by 154 00:10:06,800 --> 00:10:10,560 Speaker 1: treating your skin gently, protect it if you're going to 155 00:10:10,600 --> 00:10:13,480 Speaker 1: be handling harsh chemicals or going out in the sun, 156 00:10:13,960 --> 00:10:18,240 Speaker 1: and don't over cleanse after all, if your skin is 157 00:10:18,280 --> 00:10:21,560 Speaker 1: your castle, your first duty is to respect such a 158 00:10:21,559 --> 00:10:29,720 Speaker 1: grand structure. Today's episode is an original written by me. 159 00:10:30,640 --> 00:10:33,760 Speaker 1: Brain Stuff is production of iHeartRadio, produced by Tyler Klang. 160 00:10:34,320 --> 00:10:37,400 Speaker 1: Four more podcasts my heart Radio, visit the iHeartRadio app, 161 00:10:37,559 --> 00:10:50,400 Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.