What process accounts for the damaging effects of the sun's radiation?
A) Initiation of an autoimmune response
B) Compensatory increases in melanin production
C) Damage to epidermal cell DNA and free radical production
D) Hyperkeratinization and the formation of microscopic, subcutaneous lesions
Ans: C
Feedback:
Ultraviolet B (UVB) radiation is primarily responsible for sunburns, and it acts mainly on the cells in the basal layer of the epidermis, producing direct damage to the DNA and other nuclear proteins. It also provokes free radical production and induces a significant reduction in skin antioxidants, impairing the ability of the skin to protect itself against the free radicals that are generated. UV radiation does not provoke an autoimmune response or hyperkeratinization, although there is an inflammatory response. Increased melanin production is a protective mechanism and does not participate in the deleterious effects of UV radiation.
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