photo.jpg

# Clinical View 6.1: UV Radiation, Sunscreens, and Sunless Tanners The sun creates three forms of ultraviolet radiation: UVA, UVB, and UVC. - UVA: 320-400 nanometers - UVB: 290-320 nanometers - UVC: 100-280 nanometers UVA rays are known as tanning rays while UVB are called burning rays. UVA rays c...

# Clinical View 6.1: UV Radiation, Sunscreens, and Sunless Tanners The sun creates three forms of ultraviolet radiation: UVA, UVB, and UVC. - UVA: 320-400 nanometers - UVB: 290-320 nanometers - UVC: 100-280 nanometers UVA rays are known as tanning rays while UVB are called burning rays. UVA rays can cause burning and suppress the immune system. Both UVA and UVB rays can cause skin cancer. ## Sunscreens Sunscreens are lotions that block UVA and UVB rays. They can help protect the skin. ## Sunless Tanners Sunless tanners create a tanned look but do not protect from UV rays. They use dihydroxyacetone (DHA), which interacts with the amino acids in the cells to produce a darkened, brownish color. ## Skin Markings - **Nevus** (mole): a harmless, localized overgrowth of melanocytes - **Malignant Melanoma**: a cancerous nevus, usually resulting from excessive UV light exposure - **Freckle**: a yellowish or brown spot that represents increased melanocyte activity - **Hemangioma**: a benign tumor caused by proliferation of blood vessels - **Capillary Hemangioma**: a strawberry-colored birthmark - **Cavernous Hemangioma**: a port-wine stain, usually present at birth ## Friction Ridges Friction ridges are found on the palms, fingers, soles, and toes. - They increase friction to help grasp items and walk - They help deform the skin without being damaged - The study of friction ridges is called dermatoglyphics Friction ridge patterns are unique identifiers because no two individuals share the same set of fingerprints. Dermatoglyphics has become a valuable identification tool for law enforcement.