The Power of Your Skin!

Did you know your skin was a part of your immune system? Well now you do! While reading IMMUNE, I learnt that our skin has the most complex defense mechanisms against pathogens. Essentially what happens is around 1 millimeter deep beneath your skin is where your basal cells start duplicating skin cells. Your skin cells produce a lot of keratin, a substance that makes up the tough parts of your nails which serves as a vital element in preventing invasions. New skin cells are constantly being made, so the older ones are gradually pushed towards the surface of your skin. Halfway to the top, your skin cells develop a "spike" like structure called desmosomes that interlock with each other to form a dense wall. Next the skin cells manufacture lamellar bodies, which are tiny bags that squirt out fat to create a waterproof and impermeable coat that covers the cells and the little bit of space left between them and the desmosomes. This coat of fat not only is a border that can prevent invasions, but it also makes it easier to dispose dead skin cells and is filled with antibiotics called defensins that can murder invaders.

Keep in mind that all this is done within one millimeter deep beneath the surface of your skin, and we're not even done yet!

The final job of the cell is, ironically, to die. A neat carpet of dead skin cells at the surface of your skin is what you see when you look into a mirror! This dead layer of skin is what makes viruses and bacteria hard to invade, as these dead cells are constantly being shed making pathogens hard to adhere to our body. Moreover, viruses invade by infecting live cells, so the dead skin layer acts as the perfect barrier against them.

Last but not least, our skin is covered in a thin film of acid, called the acid mantle. They are secreted by glands below our skin, which helps protect us by lowering the pH of our skin by just a bit - enough to discomfort bypassing pathogens. It's uses extend beyond a touch of discomfort, though, as when pathogens invade they would have adapted to the lower pH levels of our outer skin, but not the alkaline environment of our blood, hindering the invasion process.

This goes to show the amazing and complex organ that is our skin. Although it is the second most popular place for bacteria to hang out (stomach is the most popular!), it houses a microbiome that we ought to appreciate.