1. Human Bio 11

2. *Ultraviolet radiation has three different wave lengths – UV-A, UV-B, and UV-C. UV-Astarts the tanning process before the skin burns and has the least cancer risk. UV-Bthe tan is darker and longer lasting but tends to produce burns before it tans. It is a known cancer risk. UV-Chas most energy but the least penetrating. Dead layers of skin stop UV-C radiation, but it is dangerous to living cells having carcinogenic effects. The sun produces rays….

3. Ultraviolet Spectrum 100-280280-210310-400 UVC UVBUVA X rays Visible

4. Skin Cancer

5. The major factor in skin cancer formation is sun exposure Skin type is also important in dictating how the skin reacts to the sun

7. Basal Cell Carcinomas Commonest skin cancer in Caucasian populations Major cause is sun exposure Common sites on face and trunk Not metastatic

9. Squamous cell carcinoma Second most common skin cancer in Caucasian populations Caused by sun exposure - chronic sun exposure Most at risk are those with pale skin who burn in the sun Commonest on sun exposed areas Pre-cancerous lesion is the solar keratosis Metastatic potential - to regional lymph nodes, then liver, lungs etc

13. Melanoma Third most common skin cancer Caused by severe intermittent bouts of sun exposure Found on sun exposed and non-exposed sites Second most common cancer to affect young women High metastatic potential - local, lymph nodes, lung, liver and brain

14. Melanoma 30% arise in a pre-existing mole –Features to look out for are asymmetry of the mole, irregular shape and irregular colour

18. How can we prevent long term skin damage? Avoid sun Avoid midday sun Use photo-protective clothing, hats etc Use sunblocks

19. Sand SEA

20. How sunscreen works Work either by reflecting or absorbing UV rays Most sunscreens protect us from UV-A and UV-B. Ingredients like zinc oxide or titanium oxide reflect or scatter ultraviolet (UV) radiation. Octyl methoxycinnamate (OMC) or oxybenzone absorb UV radiation, dissipating it as heat.

21. Sun Protection Factor Indication of the amount of time it is safe to spend in the sun without burning Ex: an SPF of 10 would allow an exposure ten times greater than normal