Which function is performed by the skin?

• A. Breaks down proteins for digestion
• B. Synthesizes vitamin D
• C. Regulates blood glucose levels
• D. Stores excess nutrients

Answer: (B)

The correct answer is that the skin synthesizes vitamin D. The skin plays a vital role in the body’s ability to produce vitamin D in response to sunlight exposure. When ultraviolet (UV) rays from the sun hit the skin, they trigger a chemical reaction that converts a cholesterol derivative in the skin into vitamin D3, which is then transformed into its active form by the liver and kidneys. This vitamin is essential for maintaining calcium and phosphorus balance in the body, promoting bone health, and supporting the immune system.

The other options, while important functions that different organs or systems perform, do not pertain to the role of the skin. The breakdown of proteins for digestion is a function of the digestive system. Regulating blood glucose levels is primarily done by the pancreas and involves hormones such as insulin and glucagon. Storing excess nutrients mainly occurs in the liver and adipose tissue. Thus, the unique ability of the skin to synthesize vitamin D directly connects it to maintaining overall health, particularly relating to bone and immune function.