True of false: The skin is an organ.
An organ? Doesn’t an organ have to be an active, self-contained part of the body that works together with other body parts for the benefit of the whole – like the heart, lungs, or pancreas? You may be thinking that the skin isn’t worthy of the title “organ,” given that it appears to be very different from those other structures. But the answer is “true”.

The skin is actually a beehive of anatomical activity. It’s not only an organ, it’s the body’s largest organ, making up 16 percent of the body’s weight. Its functions are many and varied: it’s a waterproof covering that protects us from foreign substances and the sun’s harmful rays; it manufactures, in response to sunlight, vitamin D for the rest of the body; and it serves as a sensory organ that senses touch, pressure, pain, and changes in temperature. Our skin can also be a reflection of our general health — a clear indication of its interrelationship with the other organs of the body. Understanding more about the anatomy of the skin helps us appreciate not only its marvelous complexity, but also the importance of taking care of this vital organ.

Three layers, multiple functions
The skin we see is only the first of three layers. This top layer is called the epidermis and it lies above the dermis and the subcutaneous tissue. The epidermis keeps most foreign substances (for example, bacteria) out and fluids in. Cells at the very top of the epidermis are continuously shed, replaced by new cells in an ongoing process of renewal.

The dermis is the middle layer and it’s home to a network of blood vessels and nerve endings, as well as sweat glands, oil glands and hair follicles. Overall, the dermis is held together by a strong protein called collagen and elastic fibers called elastin.

The subcutaneous tissue is the third and deepest layer of skin. It’s made up mostly of collagen and fat, which conserves body heat and serves as a first-line shock absorber for the body.

Prepared to protect
It’s the pigment melanin, produced by melanocytes, that gives skin its color. According to Doylestown Hospital dermatologist Anthony Santoro, MD, the amount of melanin produced by melanocytes as well as how densely the melanin is ‘packaged’ and dispersed throughout the epidermis is what determines whether we have fair skin, olive skin, brown skin, or any shade in between. When skin is exposed to excessive sunlight, melanocytes kick into action and produce extra melanin in an effort to darken the skin and protect it by absorbing more rays. In fair-skinned people, there may not be enough melanin available to offer this protection, and the skin burns. However, people with dark skin will become even darker – also an indication that they have been exposed to too much sun.

Either scenario is something to be concerned about, since repeated, excessive exposure to ultraviolet radiation from the sun can alter the genes of skin cells, which can result in skin cancer. Too much sun is not the only culprit, either. Tanning salons also pose a threat, says Dr. Santoro. “Studies have shown that after just 12 sessions, the risk of skin cancer increases.”

Another particularly interesting way the skin protects the body is the action of the tiny erector muscles, which are anchored in the skin and attached to every hair. During cold weather, the erector muscles contract and lift the hair a bit to create an insulating dead space between the scalp and the hair. Thisminimizes the escape of heat from the body. For reasons not entirely understood, the same thing can occur when we’re angry or afraid; we call it goose bumps.

Time… and the elements… take their toll
As we age, our skin naturally changes. In this natural aging process, the production of collagen – the protein that helps hold things together – slows, and elastin – the fibers that enable skin to snap back into place – loses some of its spring. Without firm support, the skin begins to sag. Some of the fat in the subcutaneous layer is also lost, which can cause a hollowed or flat look, especially in our hands and neck. All things being equal, heredity determines when these events will unfold for us. But if the skin has been damaged by too much sun, all things are definitely not equal.

Most premature aging of the skin is caused by sun exposure, with ultraviolet B (UVB) and ultraviolet A (UVA) rays each contributing to the damage. UVB rays are the burning rays associated with sunburn that, over time, cause the skin to get thicker in an effort to protect delicate tissue. UVA rays break down collagen and attack elastin. The combined result? Skin becomes leathery, wrinkled, and loose far earlier than it normally would. Fortunately, the consistent use of a broad-spectrum sunscreen (one that protects against both UVA and UVB) can go a long way toward preventing sun damage.

Protector, vitamin D factory, and exquisitely sensitive sensor, our skin is a dynamic organ that is literally part of the face we show the world every day. And although the years may eventually rob us of the firmness of youth, they need not rob us of our beauty. That’s because there is an instantly available – and free – enhancement that can restore the beauty of our visage in the blink of an eye. It’s called a smile.