Greetings future doctors! In lieu of a visit to our infectious disease ward this month, I thought I would lead you on a fun journey to better understanding how our skin works. After all, it’s difficult to determine a bot fly infection vs. a seriously nasty spider bite if you don’t have a basic understanding at a minimum of how skin works.
Starting on page 72 of Structure and Function of the Body (our K12 anatomy textbook), the integumentary system is composed of the skin and its ‘accessory structures’ such as the hair, nails, sweat glands, and sensory organs. Also, it has the capacity to regulate temperature by sweating and regulating blood flow near the surface of the skin. Without skin, we would be defenseless against chemicals entering our bodies, harmful bacteria, and other no see ‘ums that could make us very ill.
The skin makes up the largest organ of the integumentary system and weighs around 16 lbs. in the average adult. It has several layers including the epidermis, dermis, and subcutaneous.
The skin could be compared to that seven layer dip my mom makes on very rare occasions. Unless you’re a cannibal, however, it’s not gonna taste nearly as good. Each layer of the skin has a part to play, and the epidermis is at the top of it all. While that might sound impressive, and on some levels it is, the epidermis is actually described in the book as a “relatively thin sheet of stratified squamous epithelium.” Very anticlimactic definition for such a cool name. Of course, before we start beating up on poor ol’ epidermis, let’s just remember it’s in charge of reproducing the cells that let us heal. In the innermost layer of the epidermis lies the stratum germinativum. Gotta love it when even spellcheck doesn’t recognize the name. Anyways, the cells there are constantly reproducing to make up for the ones lost. They float to the top of the skin to begin their duty of protecting us from harmful outside anything.
When they near the top of the skin, these cells kick out the cytoplasm and replace it with something called keratin. Keratin basically provides the armor for these flaky cells, giving them a protective, waterproof layer.
The dermis is the deeper, and yet not a philosopher, layer. Whilst it’s not up there protecting us from all the nasty little bugs that try to inch their way in, it’s actually thicker than the epidermis. One thing that separates them is that, unlike the epidermis which is a bunch of cells tightly packed together, the dermis is actually made up of mostly connective tissue. The dermis is pretty much responsible for housing our network of nerves and nerve endings. The dermis lets us feel things such as pain, pressure, etc. There are two layers to the dermis: the Papillary and the Reticular.
Admittedly, when I looked at the picture of the papillae of the Papillary layer in my anatomy book, I got a little grossed out. Bumps remind me less of, “oh, look! It’s the Papillary layer!” and more of, “oh look! Skin infections!” But, the Papillary is just that; a bunch of bumps. The Papillary is made up of loose tissue, and elastic fibers. These bumps play a major role in the bromance between the epidermis and the dermis. While it’s not the only magical binder of the layers of the skin, I’m sure, the papillae at the very least deserves an honorable mention. The Papillary is also responsible for the grooves in your skin, such as fingerprints. That’s right, the government can track you down all because of the Papillary Layer.
Of course, that potential violation of your civil liberties isn’t nearly so awful when you realize you can blame the Reticular layer for wrinkles. This dense layer is made up of tough interlacing fibers, but they’re also elastic fibers present. This layer is meant to give the skin its natural hardiness whilst also letting it keep its natural, yet limited, stretchiness. However, when we get older, these elastic fibers become less frequent; ergo, wrinkles.
The last, but not least, layer of the skin is the subcutaneous. It’s almost not a layer. The subcutaneous’ purpose is to be the link between the two main layers of the skin and what’s beneath the skin. This is the layer that gives our skin the “relative mobility of the skin.” If you think I do, you’ll immediately realize that this is the layer to blame for when your thighs jiggle. But…
That’s not the point. The point is, all of these layers are important. But, seeing as most people want you to pick your favorite despite all of them being necessary for healthy skin, I’d like to argue that the epidermis is the most important part of the skin. The epidermis is around to protect the body, and is constantly working to reproduce the cells we shed just by existing. That’s a lot of hard work, and it deserves a shout out and a possible thank you. Plus, the epidermis doesn’t give us any of those less-than-desirable side effects like wrinkles and jiggly thighs.
