Which role does the skin play in the synthesis of vitamin D?

• A. The skin converts cholesterol into vitamin D3 using UV radiation.
• B. The skin stores vitamin D for later use in the body.
• C. The skin releases vitamin D directly into the bloodstream.
• D. The skin synthesizes vitamin D from dietary sources.

Answer: (A)

Verified step by step guidance

1. Understand that vitamin D synthesis in the skin is initiated by exposure to ultraviolet (UV) radiation from sunlight.
2. Recognize that the skin contains a cholesterol derivative called 7-dehydrocholesterol.
3. Learn that when the skin is exposed to UVB radiation, 7-dehydrocholesterol is converted into previtamin D3.
4. Know that previtamin D3 undergoes a heat-dependent transformation into vitamin D3 (cholecalciferol) within the skin.
5. Realize that vitamin D3 is then released into the bloodstream, where it is further processed by the liver and kidneys to become the active form of vitamin D.