What is the primary function of melanin in the epidermis?

• A. To protect the skin from UV damage.
• B. To regulate body temperature
• C. To excrete waste
• D. To produce vitamin D

Answer: (A)

Melanin’s main job in the epidermis is to act as a natural shield against ultraviolet radiation. It absorbs and dissipates UV rays from sunlight, helping protect skin cells from DNA damage that can lead to skin cancer and premature aging. Melanin is produced by melanocytes in the stratum basale and is passed to nearby keratinocytes, forming a protective layer around skin cell nuclei. When UV exposure increases, melanin production rises, giving darker skin or a tan as a protective response.

Other options aren’t the primary role of melanin. Regulating body temperature involves sweat glands and blood flow, excretion is handled by the excretory system, and while UV exposure enables vitamin D synthesis in the skin, melanin itself does not produce vitamin D; it modulates UV penetration, which can influence how much vitamin D is formed.