The skin is the largest and most exposed organ of the body. And it’s made up of three different layers. The subcutaneous is the deepest layer, made up of connective tissue and insulating fat. Next up is the dermis layer. This layer has a lot going on. Basically, temperature regulation, hair growth, and oil and sweat are controlled here. And on top is the epidermis layer – the layer you can see when you look at your skin.
This elastic layer of your skin is continually being regenerated. And it contains different types of cells with different responsibilities. These include:
- Keratinocytes – These are the main cells that make up the epidermis. They’re formed at the base, and work their way up to the top. These cells are still alive at this stage.
- Corneocytes – These cells are basically dead and flattened keratinocytes. They make up the exposed, outer layer of the epidermis. And they protect the rest of your skin from the elements.
- Melanocytes – Just as the name hints, this layer produces the melanin pigment. And it protects the skin against UV radiation. It also gives skin its color.
The epidermis itself contains 5 main layers that work to provide a protective barrier between your body and the rest of the world. These layers are called the stratum corneum, stratum lucidium, stratum granulosum, stratum spinosum, and the stratum germinativym. Fun fact: a few of these layers of skin are only in certain parts of your body!
This is the outermost layer of the epidermis. And it consists of just dead skin cells (corneocytes). It’s a small layer, consisting of 15 to 20 flattened, dead skin cells. And since they’re dead, they don’t have a nuceli or cell organelles. These cells contain dense keratin, which can absorb water very easily. And this aids in skin hydration. Plus, this layer is responsible for the elastic quality of skin. This layer is also known as the horny layer or the cornified layer.
As a special type of skin, this translucent layer is found only in the palms of your hands and the soles of your feet. You can actually feel a difference between this skin and the other skin on your body. And, in fact, this skin is thicker with 5 epidermal layers instead of 4.
This granular layer is where living keratinocytes cells start to turn into dead corenocyte cells. Also this layer contains fats, or lipids, which work to seal your skin and protect it from water going any deeper. And this is actually one of the thinner layers of your skin, if not the thinnest in some areas.
Also known as the spinous layer, this layer mainly aids your skin with flexibility. And it helps the epidermis withstand the harsh effects of abrasion and friction. Also, this layer is thicker in the soles of the feet and the palms of the hands. Which makes sense, as these areas experience more contact with external surfaces than other parts of your skin. This layer is also called the prickly layer, because it contains spiky microfilaments, which work as structural reinforcements.
As the deepest layer of the epidermis, this layer mainly consists of proliferating keratinocytes. Also known as the basal layer of the skin, this layer produces germinal cells. Like the name suggests, germinal cells are cells from which other cells are produced. And a thin membrane separates the dermis from these forming cells.