Endogenous Vitamin D Synthesis Begins In

Question

Endogenous vitamin D synthesis begins in:
A)The intestines.
B)The kidneys.
C)The liver.
D)The skin.
E)Bone tissue.

Accepted Answer

Endogenous vitamin D synthesis begins in the skin, specifically in the epidermal layer. When skin is exposed to UVB radiation from sunlight, a form of cholesterol in the skin is converted to Vitamin D3. This form of Vitamin D then undergoes further activation in the liver and kidneys.