The Role Of The Skin

Compared to the evolution of the sun, the concept of tanning indoors is fairly young and we continually are discovering new ideas, concepts and facts that were previously unknown. A salon owner or operator needs knowledge of how to run a successful business as well as an understanding of the biology of the skin and the process of tanning.

The skin is body’s largest organ. The skin of an average adult weighs eight to 10 pounds and has an average area of about 22 square feet. The skin’s purpose is to protect the body against injury, infection, heat, cold, and store water, fat and vitamins. The human skin is rejuvenated about once every four weeks.

Thinking of the skin as an organ, rather than something that can be used and abused, puts things in proper perspective. The skin is a wonderfully resilient organ and, for the most part, can survive virtually any form of punishment. The skin is the body’s boundary, tough enough to resist all sorts of environmental assaults, yet sensitive enough to feel a breeze.

A versatile organ, skin creates the first line of defense against possible invasion by bacteria and germs, while maintaining the body’s internal environment to within a few degrees of normal throughout our lifetimes. The skin also secretes fluids that lubricate it and barricade toxic substances, while maintaining this environment. The skin can absorb some soluble substances.

It is the production of melanin that results in the golden look a tanner desires. Without melanin, the skin would burn when exposed to ultraviolet light. Fortunately, melanin gives a cosmetically pleasing appearance to the skin. The process is rather intricate. First, let’s take a look at the basic structure of the skin. (1) The hypodermis (subcutis) stores fat droplets and serves as a shock-absorbing cushion. (2) The corium (true skin) consists of resilient connective tissue and acts as a "girdle" supporting the body. The outer part of the corium contains blood vessels and nerve endings. (3) The germinative layer is one of two layers within the epidermis (cuticle). (4) The horny layer is the uppermost layer of the epidermis.

The skin comes equipped with special cells called melanocytes. When these cells are stimulated by ultraviolet light, they utilize an amino acid called tyrosine to produce the pigment melanin. The cells can store small amounts of tyrosine. The melanin pigment is only able to absorb ultraviolet light of approximately 320 nm, therefore, UVB rays are needed to achieve melanin production. UVA can formulate melanin, but only when there is enough photosensitizing material already in the skin to trigger a UVB reaction. Melanin is defined as a dark pigment found in the retina, hair and skin, except for the palms of the hands, soles of the feet and lips.

Pigment Production

Melanin granules are pink in color and are formed in the melanocytes, the production cells for new pigment grains. Pigment travels upward toward the horny layer of the epidermis where it is stored around the nuclei of keratin cells. Keratin is a strong, fibrous protein that is the basic substance of nails, hair and the horns and hoofs of animals. These cells are forced outward during the tanning process and harden on the surface where they eventually disappear through flaking.

Because of this process, we are constantly developing new skin every four to eight weeks. In this way then, the pigment protects the UVB-sensitive DNA located inside the cell nuclei without obstructing the other positive effects of ultraviolet light, such as vitamin D synthesis. Energy absorbed by pigment granules is returned to the cell in the form of heat. In the beginning stages of melanin production, the skin has very little protection. This is why the importance of slow tanning is emphasized. UVA penetrates deeper than UVB, causing damage to the corium. Damage to this layer of the epidermis hastens aging and destruction of collagen and connective tissue. A UVA burn can be much more damaging because it is not felt due to its deep penetration. This is why moderate tanning is a must.