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Skin Anatomy

Healthy normal skin is the desire of all to possess. Healthy skin is important, as people assess each other based on skin appearance before any other attribute.

 

Skin appearance is the result of many inter-related biochemical and many other factors including lifestyle and dietary habits that you choose, ultraviolet radiation, alcohol consumption, tobacco abuse, and environmental pollution. In addition, few people realize that as their body weight increases and their blood sugar levels rise, biochemical reactions disrupt the very structural framework of their skin. Combined, these factors lead to cumulative deterioration in skin appearance and function.

 

Skin Functions

Skin is central in the social and visual experience, as it clearly reflects the consequences of aging. One of the most important factor in premature aging is inflammation that can be caused by an infection or allergy. “Inflammation is an immune reaction” on a cellular level to an irritant, can show up on our skin in the form of puffiness, wrinkles, enlarged pores, sagging, blotchiness, and reddening of the skin. However, much inflammation is caused by lifestyle factors that we can control or mediate.

If you practice a healthy diet and a great skin care routine, keeping chemicals out and giving skin the proper nourishment, you’ll achieve a healthy looking skin. Beauty is one of the most important factors which affect your personality and confidence. One great approach in maximizing skin wellbeing and appearance, is to know the functions of 3-important layers of the skin, “ Epidermis, Dermis and Subcutis“. Your skin as a sophisticated organ needed more pampering and focus for your healthy glow and anti aging care because it could mean taking years off your face and slowing the progression of premature aging. Professional skin care treatments and non-toxin products maintains skin in its most attractive and healthy state.

The skin is the largest organ in the body, comprising about 15% of the body weight. The total skin surface of an adult ranges from 12 to 20 square feet. In terms of chemical composition, the skin is about 70% water, 25% protein and 2% lipids. The remainder includes Trace Minerals, Nucleic Acids, Glycosoaminoglycans, Proteoglycans and numerous other chemicals. The skin is an ever-changing organ that contains many specialized cells and structures. The skin functions as a protective barrier that interfaces with a sometimes-hostile environment. It is also very involved in maintaining the proper temperature for the body to function well. It gathers sensory information from the environment, and plays an active role in the immune system protecting us from disease. Every element within the warmth/airy/watery/solid domains also finds its reflection in the skin. If the skin is a "mirror" of the whole human being, then external skin diseases are mirrors of in­ternal pathological disturbances.

 

Understanding how the skin can function in these many ways starts with understanding the structure of the 3 layers of skin - the Epidermis, Dermis, and Subcutis (subcutaneous tissue).

 

Epidermis:

The epidermis is the outermost layer of the skin, and protects the body from the environment, the total thinkness of the epidermis is usually about 0.5 - 1 mm, the thickness of the epidermis varies in different types of skin; it is only .05 mm thick on the eyelids. The epidermis layer itself is made up of five sublayers that work together to continually rebuild the surface of the skin: Stratum corneum surface is actually composed of dead skin cells that were made at the bottom of this layer and have risen to the top, continuously slough off and are replaced by new ones coming from below.

 

The condition of epdermis determines how "fresh" your skin looks and also how well your skin absorbs and holds moisture. Another significant group of cell in the epidermis are melanocytes, the cells producing melanin, found in the basal layer of the epidermis, responsible for depth of skin color. Langerhans cells in the skin, is the only cells able to 'see' and 'alert' other responding immune cells to initiate a protective response against harmful foreign invaders. "The condition of epdermis determines how "fresh" your skin looks and also how well your skin absorbs and holds moisture".

 

Dermis:

The dermis is the thickest of the three layers of the skin (1.5 to 4 mm thick), making up approximately 90 percent of the thickness of the skin. The main functions of the dermis are to regulate temperature and to supply the epidermis with nutrient-saturated blood. Much of the body’s water supply is stored within the dermis.

 

 

The dermis layer is made up of two sublayers:

The Papillary Layer: The upper, papillary layer, contains a thin arrangement of collagen fibers. The papillary

layer supplies nutrients to select layers of the epidermis and regulates temperature. Both of these functions are accomplished with a thin, extensive vascular system that operates similarly to other vascular systems in the body. Constriction and expansion control the amount of blood that flows through the skin and dictate whether body heat is dispelled when the skin is hot or conserved when it is cold.

 

The Reticular Layer:

The lower, reticular layer, is thicker and made of thick collagen fibers that are arranged in parallel to the surface of the skin. The reticular layer is denser than the papillary dermis, and it strengthens the skin, providing structure and elasticity. It also supports other components of the skin, such as hair follicles, sweat glands, and sebaceous glands.

 

 

The dermis contains the following:

Blood vessels; the blood vessels supply nutrients and oxygen to the skin and take away cell waste and cell products. The blood vessels also transport the vitamin D produced in the skin back to the rest of the body.

 

Lymph vessels; the lymph vessels bathe the tissues of the skin with lymph, a milky substance that contains the infection-fighting cells of the immune system. These cells work to destroy any infection or invading organisms as the lymph circulates to the lymph nodes.

 

Hair follicles; the hair follicle is a tube-shaped sheath that surrounds the part of the hair that is under the skin and nourishes the hair.

 

Sebaceous (oil) glands;  sebacious glands, located around hair follicles and can be found everywhere on the body except for the palms of the hands and the soles of the feet, are of particular importance for skin health as they produce sebum, an oily protective substance that lubricates and waterproofs the skin and hair. When sebacious gland produce too little sebum, as is common in older people, the skin becomes excessively dry and more prone to wrinkling. Conversely, overproduction or improper composition of sebum, as is common in adolescents, often leads to acne.

 

Sweat glands; the average person has about 3 million sweat glands. Sweat glands are classified according to two types: Apocrine glands are specialized sweat glands that can be found only in the armpits and pubic region. These glands secrete a milky sweat that encourages the growth of the bacteria responsible for body odor.

 

Eccrine glands; are the true sweat glands. Found over the entire body, these glands regulate body temperature by bringing water via the pores to the surface of the skin, where it evaporates and reduces skin temperature. These glands can produce up to two liters of sweat an hour, however, they secrete mostly water, which doesn’t encourage the growth of odor-producing bacteria. Fibroblasts: The dermis is held together by a protein called collagen, made by fibroblasts.

 

Fibroblasts are skin cells that give the skin its strength and resilience. In the skin, collagen supports the epidermis, lending it its durability. Elastin, a similar protein, is the substance that allows the skin to spring back into place when stretched and keeps the skin flexible. (Aging is associated with a loss of fibrous tissue), slower rate of cellular renewal, and a reduced vascular and glandular network. Barrier function that maintains cellular hydration also becomes impaired. The subcutaneous tissue (hypodermis) flattens, particularly in the face, hands and feet.

 

Nerve Endings:

The dermis layer also contains pain and touch receptors that transmit sensations of pain, itch, pressure and information regarding temperature to the brain for interpretation. If necessary, shivering (involuntary contraction and relaxation of muscles) is triggered, generating body heat. The dermis is the layer responsible for the skin's structural integrity, elasticity and resilience. Wrinkles arise and develop in the dermis.

 

Subcutis (Subcutaneous tissue):

The Subcutis is the deepest layer of skin, and consists of a network of collagen and fat cells, and is responsible for connected muscle tissue, bone, and skin. Subcutis fat acts as a shock absorber and heat insulator, protecting underlying tissues from cold and mechanical trauma, and protecting the inner organs. It also stores fat as an energy reserve for the body, the thickness of the subcutis layer varies throughout the body and from person to person. Sweat glands and minute muscles attached to hair follicles originate in subcutaneous tissue. The loss of subcutaneous tissue, often occurring with age, leads to facial sag and accentuates wrinkles.

Skin Aging

The skin gradually changes as you get older and to keep your skin looking its best, your skincare regimen should address the unique needs of each decade. Understanding the physiologic changes that are occurring in each decade can help you to better take care of your skin. It’s never too late to attain healthy skin; read below for some of the best ways you can attain healthy skin if you are in your 30s or older.

 

In 30s:

Most women start to see the first signs of aging in the early to mid-30s. These signs are accelerated in those who have spent extensive time in the sun in their teens and 20s.

 

The result:

*Skin appears drier  *Fine expression lines and wrinkles begin to appear *Uneven complexion and sunspots *Skin starts to lose some of its youthful glow.

 

In 40s Many of the changes that started to appear in the 30s are more pronounced in the 40s. During this decade the skin changes are primarily due to premenopausal changes occurring inside the body. Skin cells start to turn over even more slowly than in the 30s. The skin’s collagen starts to break down. The skin’s elastic tissue starts to lose some of its elasticity.

 

The result:

*Skin gets drier  *Skin appears duller *Skin starts to lose tightness *Fine expression lines appear around the eyes and mouth *Signs of photo-aging increase (e.g., sunspots, blotchiness, unevenness, lines).

 

In 50s:

By this decade the changes seen in the 40s are more pronounced. As estrogen levels drop post-menopause, the skin’s natural oil production decreases due to the reduced size of the oil glands. The result is even drier skin. The skin also gets more fragile, therefore it is injured easily and is slow to heal. There is also increased loss of elasticity, especially around the eyes. The skin around the neck may also start to droop.

 

The result:

*Skin looks dry and lackluster *Skin is more sensitive to aggressive anti-aging products *Expression lines and wrinkles are deeper *Eyelids begin to wrinkle *Neck starts to droop.

 

In 60s:

The signs of aging are more pronounced in the sixth decade. Wrinkles are well-defined. The effects of gravity on the eyelids, neck, peri-oral area and jawline are more marked.

 

References: Newer Light Therapy for Acne (archive) U.S Food and Drug Administration, FDA Consumer, November–December 2002, Thiboutot, Diane M.; Strauss, John S. (2003). "Diseases of the sebaceous glands". In Burns, Tony; Breathnach, Stephen; Cox, Neil; Griffiths, Christopher. Fitzpatrick's dermatology in general medicine (6th ed.). New York: McGraw-Hill. pp. 672–87. Anderson, Laurence. 2006. Looking Good, the Australian guide to skin care, cosmetic medicine and cosmetic surgery. AMPCo. Sydney. Arndt, Hsu, Kenneth, Jeffrey (2007). Manual of dermatologic therapeutics. Lippincott Williams & Wilkins. Biomaterials, August 2009, pp. 6035–6040; Dermatologic Clinics, January 2009, pp. 33-42; Advances in Biochemical Engineering/Biotechnology, volume 111, 2008, pp. 1–66; Journal of Drugs in Dermatology, December 2008, pp.1149–1152; January 2008, Shah SK, Alexis AF (May 2010). "Acne in skin of color: practical approaches to treatment". J Dermatolog Treat 21 (3): pp. 206–11. “acne vulgaris” and “acne rosacea" Dorland's Medical Dictionary. Skin Sentry Cells Promote Distinct Immune Responses, ScienceDaily (July 21, 2011).

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