1. What does skin do for us besides cover & protect muscles, bones & organs?

Skin (the integumentary system) does more than cover under-lying body parts. It also helps maintain our constant body temperature because it has sweat glands that can help cool the body. A certain amount of waste materials are also released with sweat, so the skin can be considered an excretory organ, also. Vitamin D is produced when skin is exposed to sunlight -- this vitamin is essential for incorporating calcium in bone matrix resulting in strong bones. (Don't over-do the sunlight exposure though, thinking it will make your bones REALLY strong! You don't need that much sunlight exposure, and you'll just get a good case of wrinkles and skin cancer.) Our skin helps us be aware of our surroundings because its sensory receptors allow us to feel heat, cold, light touch, pressure and pain. Our skin is our first line of defense against bacteria. As long as the skin is not broken (as in a cut or scratch), we have an excellent barrier against many of the bacteria in our environment. Our skin is also a waterproof barrier and helps retain important levels of water within the body. In fact, one of the major dangers of a third degree burn is that the victim has lost this vital barrier against water loss.
 
 
 

2. Is the integumentary system made up of just one kind of tissue?

No, there is actually more than one kind of tissue in the integumentary system.

The outermost layer, the layer you can touch, is stratified squamous epithelium. This layer, which includes both a layer of cells that are living & a layer of the same cells which have died, is the epidermis. Our hair & nails are produced by these cells also. There are no blood vessels in this tissue layer. The next layer, which is deep to the epidermis, is the dermis. It is mainly dense irregular connective tissue and does contain blood vessels, receptors for touch, etc., sweat (sudoriferous) glands, & oil (sebum) glands. Hair follicles are embedded in this layer, although they are formed from epidermal cells.
 
 
 

3. What causes us to have fingerprints?

Fingerprints are formed by dermal papillae, ridges on the outermost surface of the dermis which push up into the epidermal layer. They are sometimes referred to as "friction ridges" because they enable us to grip smooth objects more easily.
 
 

4. What are the danger signs of malignant melanoma, the most dangerous skin cancer?

An easy way to remember what to look for is the letters ABCD:

A is for asymmetry. Melanomas tend to be an irregular shape. They are often raised above the rest of the skin surface & may bleed or ooze.

B is for border. The edge of the suspect mole or mark may have a notched or uneven border.

C is for color. A malignant skin growth may have several different colors to it, a mottled appearance with colors that may include tan, brown, black, red, pink, white, &/or blue.

D is for diameter. The size change in the diameter of the growth is considered a danger sign, so a person needs to keep track of the size of moles. If there is growth of 5 mm or more (about 1/5 in.), this is considered a danger sign.

Figure 6A is a photograph of a cutaneous malignant melanoma.

Although there was a trend, starting in the 1920's until recently, for Caucasians to think that having a tan was fashionable, it is now recognized that tanning leads not just to wrinkles, but also to skin cancer. Sunburns do contribute to the tendency to develop skin cancers, so precautions should be taken to avoid burning, especially for children. Furthermore, there is not really a legitimate reason to visit tanning salons unless wrinkles are on your agenda!