Question:
Which of the following is necessary for the dermal synthesis of Vitamin D ?
AGamma Rays
BX-Rays
CInfrared rays
DUltraviloet rays
Answer:
D. Ultraviloet rays
Explanation:
- Vitamin D2 (ergocalciferol) is largely human-made and added to foods
- Vitamin D3 (cholecalciferol) is synthesized in the skin of humans from 7-dehydrocholesterol and is also consumed in the diet via the intake of animal-based foods.
- Vitamin D is a closely related compound. The synthesis of this vitamin starts when the precursor molecules are activated in the skin by the UV (ultraviolet) rays in the sunlight.
- In the kidneys and the liver, the enzymes then modify the molecule ultimately yielding calcitriol, which is the most active form of vitamin D.
- This calcitriol supplies the homeostasis of body fluids by assisting the process of absorption of calcium in the food.
- As per the synthesis sequence explained, vitamin D is deemed to be a hormone as it is yielded in the body in one location and transported by the blood, and shows effect in the other location.
- Hence, skin is deemed to be an endocrine organ.