So, you want to get some sun to add a little color to those pasty legs of yours, but thoughts of coming home as the human lobster are outweighing your desire to dose up on some natural vitamin D? Before heading out, test your knowledge about sunburns and suntans.
The sun's UVC radiation is filtered out by the atmosphere and never reaches us. UVA can lead to tanning of the skin, and UVB can cause sunburn.
Ultraviolet light stimulates melanocytes.
Melanocytes make melanin, the skin's pigments. When melanocytes are activated, they produce more melanin -- thus darkening the skin.
Melanocytes produce two different pigments: eumelanin (brown) and phaeomelanin (yellow and red).
Ultraviolet light causes cellular damage to the skin.
Increased capillary blood flow is a response to the cellular damage caused by exposure to ultraviolet light.
Ultraviolet light has a number of negative effects on the human body, including wrinkles and skin cancer.
Sunscreens can absorb or block ultraviolet light.
SPF stands for "sun protection factor," and is found on sunscreen labels.
SPF applies only to UVB radiation.