In zootomy and dermatology, skin is an organ of the integumentary system composed of a layer of tissues that protect underlying muscles and organs. As the interface with the surroundings, it plays the most important role in protecting against pathogens. Its other main functions are insulation and temperature regulation, sensation and vitamin D and B synthesis.

The skin is often known as "the largest organ in the human body". This applies to exterior surface, as it covers the body, appearing to have the largest surface area of all the organs. Moreover, it applies to weight, as it weighs more than any single internal organ, accounting for about 15 percent of body weight. For the average adult human, the skin has a surface area of between 1.5-2.0 square metres, most of it is between 2-3 mm thick. The average square inch of skin holds 650 sweat glands, 20 blood vessels, 1000 melanocytes, and more than a thousand nerve endings.

Skin is composed of the epidermis and the dermis. Below these layers lies the hypodermis(subcutaneous adipose layer), which is not usually classified as a layer of skin.

Blood capillaries are found beneath the epidermis, and are linked to an arteriole and a venule. Arterial shunt vessels may bypass the network in ears, the nose and fingertips.

The dermis can be split into the papillary and reticular layers. The papillary layer is outermost and extends into the dermis to supply it with vessels. It is composed of loosely arranged fibres. Papillary ridges make up the lines of the hands. The reticular layer is more dense and is continuous with the hypodermis. It contains the bulk of the structures (such as sweat glands). The reticular layer is composed of irregularly arranged fibres and resists stretching.

The constantly peeling off dead cells of the epidermis mix with the secretions of the sweat and sebaceous glands and the dust found on the skin to form a filthy layer on its surface. If not washed away the dirt and dead skin slurry begins to decompose emitting a foul smell.

Functions of the skin are disturbed when it is dirty and it becomes more easily damaged. The release of antibacterial compounds decreases. Dirty skin is more prone to develop infections. Cosmetics should be used carefully because these may cause allergic reactions. Each season requires suitable clothing in order to facilitate the evaporation of the sweat. Sunlight, water and air play an important role in keeping the skin healthy.

The skin supports its own ecosystems of microorganisms, including yeasts and bacteria, which cannot be removed by any amount of cleaning. In general these organisms keep one another in check and are part of a healthy skin. When the balance is disturbed, e.g., by antibiotics which kill bacteria, there may be an overgrowth and infection by yeasts. The skin is continuous with the inner epithelial lining of the body at the orifices, each of which supports its own complement of flora.

You are never too young or too old to start taking care of your skin. In fact, skin care and protection should be an essential part of your health, fitness, and beauty regime.

If you take care of your skin, your skin will take care of you! But with all of the lotions, creams, and potions on the market, it can be difficult to know which product will work for you. Many products claim to remove wrinkles or heal dry skin. Others claim to contain expensive ingredients that they say will improve the effects of the product.

The first step to taking care of your skin is preventing damage. Sun, wind, pollutants, and simply aging can degrade the condition of your skin. Common complaints include dry and itchy skin, wrinkles, sagging, color changes, and age spots. There are steps that you can take to keep you skin looking and feeling its best.

Exercise, rest, and good nutrition lay the foundation for beautiful, healthy skin, inside and out. A proper diet is not only good for your overall health, it also helps to ensure that your skin will receive all of the vitamins, minerals, and nutrients that it needs to maintain and repair cells. Drinking purified water is another good way to keep your skin healthy. Water helps to hydrate the skin and move waste and nutrients through the system. It is very effective mixing a teaspoon or capful of Organic Apple Cider Vinegar in with your water. Do not drink Tap Water.

The most important way to care for your skin is to protect it from the damaging rays of the sun. Ultraviolet radiation damages the skin and can lead to wrinkles, premature aging, age spots, and cancer. Take extra precautions to make sure your skin is not exposed to the sun's rays. Use a natural sunscreen, or a moisturizer that contains sunscreen (at least SPF 15) everyday. Your skin does need some sunlight 10-15 minutes of direct exposure daily.

When you do use soap, try using a natural very mild soap that does not contain any dyes, parabens or perfumes. Follow up the bath with a moisturizing lotion, concentrating on problem dry areas. A good all natural moisturizer is one of the foundations for a healthy skin care regimen. Continue moisturizing throughout the day to keep skin healthy. Your hands and face are particularly susceptible to daily damage, and may need to be moisturized several times.

Wash your skin thoroughly on a daily basis to remove the dirt, debris, pollutants, and perspiration that accumulates on a daily basis. If you have dry or sensitive skin, use only warm water to wash your skin and use a mild natural cleanser every few days. If you have normal or oily skin, be sure to wash with a gentle cleanser on a daily basis. Be sure to brush your teeth before washing your face, as toothpaste residue can irritate sensitive facial skin.

Apart from the services offered at skin clinics, many creams, gels and ointments that claim to treat acne, diminish sun or age spots and enhance skin elasticity are widely available in the market. There are scrubs, cleansers, masks, over-the-counter skin medicine and skin peel formulations, all offered at various price ranges. Most can be bought at department stores or drugstores, but the fact is that very few of these so- called miracle products actually work.

As we age, our body undergoes various changes, and so does our skin. In our skin, we have tissues known as collagen and elastin. These tissues are mainly responsible for making our skin firm and stretchable. As we grow older, the amount of collagen and elastin in our skin naturally diminishes. As a result, our skin becomes less elastic and weaker, thus creating "wrinkles".

Experts say that the amount of wrinkles that a person will develop through the years also depends on the genetic make up of this individual. However, smoking, sun exposure, dry skin, and repetitive facial expressions and mannerisms such as frowning, can all enhance the creation of wrinkles that may or may not be permanently present.

For people seeking solutions to severe damage that has already been done to the skin, there are a number of treatments available ranging from chemical peels and dermabrasion to the latest and technologically advanced, computerized laser resurfacing. However, many people looking for skin repair are hesitant to try chemical or laser peels due to the painful procedure and long recuperation period they have to undergo. The results of these procedures however, are fantastic.

The important thing to remember when seeking out treatment for your wrinkles is to know first how your body can possibly react to the treatment. Get in touch with a skin doctor for things that you are not sure of, but are contemplating on trying out.

Definitions and terms

Acne

• An inflammatory disease of the sebaceous glands and hair follicles of the skin that is marked by the eruption of pimples or pustules, especially on the face.

Bacteria

• Microscopic unicellular prokaryotic organisms characterized by the lack of a membrane-bound nucleus and membrane-bound organelles.

Dermis

• The sensitive connective tissue layer of the skin located below the epidermis, containing nerve endings, sweat and sebaceous glands, and blood and lymph vessels.

Epidermis

• The outer, protective, nonvascular layer of the skin of vertebrates, covering the dermis.

Hypodermis

• A subcutaneous layer of loose connective tissue containing a varying number of fat cells.

Pimples

• A small swelling of the skin, usually caused by acne; a papule or pustule.

Ultraviolet radiation

• Invisible electromagnetic radiation between visible violet light and X rays.

Plastic surgery information