The Natural Sunscreen: Melanin
Tanning is highly controversial topic that can be hard to understand. It is public knowledge that both tanning in the sun, as well as tanning in tanning beds is bad for our skin because of the UV rays. But, what about people with tan skin?
The skin is the largest organ of the human body. It can be hard to think of the skin as an organ, but it consists of cells and tissues that perform a specific function in an organism. There are two main layers in the skin – the epidermis, or outer layer, and the dermis, or the inner layer. All of our sweat glands, hair follicles, and fat cells are stored in our dermis.
The living inner layer of our skin is called the malpighian, which is where the dead cells are created which we see. The malpighian layer has three layers, one of which is the basal layer where basal cell carcinoma starts. The outer layer of the dead cells, or the skin that we see, is filled with keratin. Keratin is very tough and is also found in in horns, hair and fingernails; it is what makes our skin so tough.
In the malpighian layer the melanocyte cell is found. Melanocytes produce melanin, which is a pigment that allows one to tan. It also is the source of melanoma cancer, which is caused by repeated over exposure to UV rays.
When one tans the melanocytes are producing melanin pigment in response to the UV rays. The melanin that is produced can absorb the UV rays, which protects the cells from sun damage. Melanin production can take some time to produce enough melanin to protect the skin. That is why most people take a few days to build a tan. After a few days of repeated exposure to the sun, if one’s body produces enough melanin, then our skin cells can be protected form the sun. There are certain skin types that continuously produce melanin, causing the skin to appear darker, and thus also have better protection from the sun.
Sunburns are when one does not produce enough melanin to protect their skin cells, thus causing UV damage and sunburn. The reasons sunburns are red is because there is an increase of blood flow to the capillary bed of the dermis in order to bring in new cells to repair the damage. Sunscreens acts to both protect our skin from UV rays as well as to absorb UV rays.