What’s Going On Down There?
Many Layers – Layers of the Epidermis
The epidermis or outer layer provides a barrier of protection from foreign particles. It varies in thickness on different parts of the body and is thickest on the soles of the feet and the hands. It is made up of cells called keratinocytes and has its own multiple layers or ‘strata’:
The Stratum Corneum (SC) (horny layer) is what you might visualize if you were told to think of what the skin actually looks like. It is made up of scale-like cells which contain keratin. They are packed tightly together and are continually being replaced by new cells underneath. This is what you slough off when you use an abrasive cleanser or cleaning tool. The Stratum Corneum layer is slightly acidic and is often referred to as the acid mantle of the skin.
The pH balance of the skin ranges from 4.5 to 6. (Remember biology now… The pH scale goes from 0 to 14 with neutral being 7. Anything higher than 7 is alkaline and anything lower than 7 is acidic.)
PH is important to understand because the proper pH level can prevent bacteria from penetrating the skin. Bacteria thinks acid is bad. Many companies stress balanced pH levels in the promotion of their skin care products for good reason. It is important for you to use products that do not strip the acid mantle or alter its pH in a harmful manner. So you could have potentially have occasional blackheads (blocked pores) on your skin from normal overproduction of sebum that would never go any further unless your acid mantle’s pH is compromised for some reason.
The Stratum Lucidum (SL) (clear layer) is very thin and only well seen where hair folicles are not present and the skin is especially thick, such as the palm of the hand or soles of the feet.
The Stratum Granulosum (SGR) (granular layer) is a median layer of cells which provide a hard substance and waterproof barrier to prevent body fluid loss. The cellular connections that provide that waterproof barrier are called desmosomal connections. The cells in the SGR are in a constant process of accumulating dense particles (keratohyalin containing lipids) as part of the skin manufacturing and maintenance (keratinization). Keratinization is the process a skin cell goes through as it gains more protein, flattens out and matures. This basic process is essential for having healthy skin.
Next is the Stratum Spinosum (SS) (prickle layer) which tops the Stratum Germinativum (SG) (basal layer) This SG layer is the place where cell manufacturing is continually going on to create more new skin cells. It takes two weeks for a new cell to make it through the layers of epidermis to the surface of your skin in a process called ‘desquamation’. As cells divide in the SG they accumulate more and more desmosomes (connections) on their outer surfaces looking very prickly as they push outward. (hence the name ‘prickle’ layer). As you grow older this whole trip takes longer as the processing plant slows down.
The very important Melanocytes also live in this ‘basal’ layer. The Malenocytes are the cells which produce Melanin, the dark pigment which blocks the sun’s ultraviolet rays from the skin cells beneath. The darker your skin is, the more melanin you have in your epidermis.
All of these layers are going on at a microscopic level. Think of this intricate puzzle the next time you ‘manhandle’ your face with rough and ready fingers. And every time you squeeze, or cut into the skin you disrupt these complex layers. Your skin will have to work twice as hard to re-build itself. And please pardon the pun, but we’ve just scratched the surface. The epidermis is the thinnest layer of the skin. It takes up only the first 10% or so.
Many Layers – The Next Layers
OK. I hope I haven’t lost you so far. Just think of it this way. Your skin is like a slice of lasagna and the epidermis only the top noodle. There is a lot more going on here than meets the naked eye. Even this top layer is a pretty complicated noodle, so stop thinking of your skin as just one simple piece of stuff that covers your body. Start to see the intricacies of skin.
The bottom layer of skin is the subcutaneous tissue which is a cushioning layer of insulating fat where energy is stored. Between these two layers is the very important dermis.
The dermis helps to regulate body temperature and serves to supply nutrients to the epidermis. It also contains immune system cells which defend the body against any infectious invader that gets through the epidermis. The dermis also consists of its own layers.
The Papillary Layer (PD) is made up of collagen and elastin (secreted by little cells called fibroblasts). They are complex proteins which give the skin support and elasticity. They are what helps your skin resilient keep its shape after it’s been stretched or pinched. This layer also contains the vascular (blood vessel) networks which support the avascular (without a vascular network) epidermis and keeps your skin nice and toasty (thermoregulation). Collagen treatments are injected into this layer of skin after time and age cause the bonds in this layer become weak.
The Reticular layer is where all of the other ‘skin action’ occurs. The tissue here is a little more dense than the PD. The pore and hair follicles ‘plunge’ through the upper epidermis and PD to delve into the heart of the dermis. Here is where you find fat cells, blood and lymph vessels, sweat glands, hair follicles, arrector pili muscles and those famous and pesky life changing sebaceous oil glands.
All of this is being fed by another system of veins and arteries. The arteries bring fresh blood filled with oxygen and nutrients to the area, the veins carrying away the blood depleted of oxygen. We will get more into this support system later on in the book, where internal functions and dysfunctions which affect the skin will be discussed.
