The epidermis is an important layer forming the skin that is mainly responsible for providing protection from the incoming harmful solar radiations, that are comprised of ultraviolet particles. These UV rays can cause various diseases like skin cancer.
When the solar radiations containing UV radiations (mostly the UV-B type radiation having a wavelength 290-315 nanometer) strikes the cells of human beings, then the protein that is stored within the skin named '7- dehydrocholesterolit (DHC)' is transformed into the vitamin d3 inside the cells.
