The Layers of your Skin

The skin is the body’s largest organ. It forms a barrier that helps prevent harmful microorganisms and chemicals from entering the body, and it also prevents the loss of body fluids. It protects the vital structures inside the body from injury and from the potentially damaging ultraviolet rays of the sun. The skin also helps regulate body temperature, excretes some waste products, and is an important sensory organ. Both delicate and resilient, the skin constantly renews itself and has a remarkable ability to repair itself after injury.




Layers of the skin


The epidermis is composed of keratinized, stratified squamous epithelium. It is made of four or five layers of epithelial cells, depending on its location in the body. It does not have any blood vessels within it . Skin that has four layers of cells is referred to as “thin skin.” From deep to superficial, these layers are the stratum basale, stratum spinosum, stratum granulosum, and stratum corneum. Most of the skin can be classified as thin skin. “Thick skin” is found only on the palms of the hands and the soles of the feet. It has a fifth layer, called the stratum lucidum, located between the stratum corneum and the stratum granulosum. The epidermis is a continually renewing layer and gives rise to derivative structures, such as pilosebaceous apparatuses, nails, and sweat glands. The basal cells of the epidermis undergo proliferation cycles that provide for the renewal of the outer epidermis. The epidermis is a dynamic tissue in which cells are constantly in unsynchronized motion, as differing individual cell populations pass not only one another but also melanocytes and Langerhans cells as they move toward the surface of the skin.


The dermis might be considered the “core” of the integumentary system, as distinct from the epidermis (epi- = “upon” or “over”) and hypodermis (hypo- = “below”). It contains blood and lymph vessels, nerves, and other structures, such as hair follicles and sweat glands. The dermis is made of two layers of connective tissue that compose an interconnected mesh of elastin and collagenous fibers, produced by fibroblasts. The dermis comprises the bulk of the skin and provides its pliability, elasticity, and tensile strength. It protects the body from mechanical injury, binds water, aids in thermoregulation, and includes receptors of sensory stimuli. The dermis interacts with the epidermis in maintaining the properties of both tissues.


The hypodermis (also called the subcutaneous layer or superficial fascia) is a layer directly below the dermis and is the deepest section of the skin. It serves to connect the skin to the underlying fascia (fibrous tissue) of the bones and muscles. It is not strictly a part of the skin, although the border between the hypodermis and dermis can be difficult to distinguish. The hypodermis consists of well-vascularized, loose, areolar connective tissue and adipose tissue, which functions as a mode of fat storage and provides insulation and cushioning for the integument. The hypodermis refers to the fat tissue below the dermis that insulates the body from cold temperatures and provides shock absorption. Fat cells of the hypodermis also store nutrients and energy. The hypodermis is the thickest in the buttocks, palms of the hands, and soles of the feet. As we age, the hypodermis begins to atrophy, contributing to the thinning of aging skin.


This is a very basic overview of the physiology of the skin to learn more refer to the American Academy of Dermatology.

How Hormones Effect Our Skin

Teens: The Oily Years
 

Girls start puberty around ages 12 or 13, sometimes this number differs based on genetics and environmental factors. During puberty, the female body starts producing sex hormones, namely estrogens and androgens, in higher quantities than before as it gears up towards adulthood.


When it comes to popular hormones, estrogen takes the prize for most widely known and discussed. However, there are many misconceptions about this elusive and incredibly important substance. First of all, it is not purely a female hormone. True, it is primarily made in the ovaries and is abundant in females, but it is also found in males and made in different tissues outside of the ovaries. Secondly, the word estrogen actually encompasses a group of chemically similar hormones, so it is not a single substance. Estrogens include estradiol, the most abundant form in adult females, estriol, the primary estrogen during pregnancy and estrone, which is produced during menopause. During puberty, estrogen also communicates to other parts of the body through specialized receptors, causing breasts to develop, for example, or giving a new curve to hips and thighs. In the skin, estrogen decreases pore size, creating a smooth surface. It also helps build collagen and elastin, proteins that give the skin its springiness and elasticity, respectively. And, it helps the skin heal and maintain moisture.


Androgens include testosterone, which is generally thought of as the male hormone, but, as with estrogen and males, testosterone and other androgens are also present in females. During puberty, a boost in androgens stimulates coarser, thicker hair growth, particularly pubic and underarm hair. In the skin, the hormones enlarge pores and boost the production of sebum, an oily substance produced in the skin.What you get is the telltale sign of teenage skin: acne.


20s to Mid-30s: The Best of Times

Estrogen peaks during your 20s, giving most women their best-ever complexion: luminous, taut, and even-toned. The shift in hormone levels around your period, however, can lead to acne.


If the cycle remains on schedule, estrogen peaks right before ovulation, which can make the skin appear to glow (this is the same hormonal boost that gives pregnant women their shining skin). Testosterone also peaks, which drastically increases the likelihood of blemishes and breakouts. The hormone also increases the libido.After ovulation, both estrogen and testosterone drop.


Late 30s and 40s: Getting Drier
                                                                                                                                  

Your 30’s are when estrogen levels start to dip, heralding sinking levels of skin-tightening collagen and elastin and skin-plumping hyaluronic acid.


As the overall level of estrogen decreases, the skin does not bounce back the same way. Instead, collagen and elastin production decreases, which causes the skin to get drier and lose its elasticity. Estrogen loss impacts aging skin far more quickly than sun damage.


By their mid-to-late 40s, most women are in perimenopause, the transition between regular ovulation and menopause, which is when ovulation stops completely. As the hormone cycles change to accommodate this new stage, you may experience adult acne, increased facial hair and a thinning head of hair.


50s and Up: Menopause Realities

Menopause has usually started once a woman is in her 50’s. The ovaries still produce hormones, including estrogen and testosterone, but the levels are very low. The main hormone that affects the skin during menopause is estrogen and, as it fades, the skin produces less collagen and elastin. During this time, the skin gets thinner, drier and more wrinkled. Menopause may cause other skin problems, including acne or rosacea.


Drops in estrogen can also cause hot flashes. These flashes can cause a sudden sensation of warmth in the face and chest, making your skin appear very red.


Every human being experiences the changing of our skin as we age, the best way to keep your skin at it’s healthiest is to have a proper skin care routine that will need to change as we age. Make sure you check in with your skin care professional to make sure you’re using the right products for your age and skin type.