https://wiki.tiffa.net/w/index.php?action=history&feed=atom&title=Translations%3AVitamin_D%2F90%2FenTranslations:Vitamin D/90/en - Revision history2026-08-13T15:52:39ZRevision history for this page on the wikiMediaWiki 1.43.0https://wiki.tiffa.net/w/index.php?title=Translations:Vitamin_D/90/en&diff=110215&oldid=prevFuzzyBot: Importing a new version from external source2024-01-25T23:41:41Z<p>Importing a new version from external source</p>
<p><b>New page</b></p><div>=== Synthesis in the skin ===<br />
[[File:Skinlayers.png|thumb|In the epidermal strata of the skin, vitamin D production is greatest in the stratum basale (colored red in the illustration) and stratum spinosum (colored light brown).]]<br />
Vitamin D<sub>3</sub> is produced photochemically from 7-dehydrocholesterol in the skin of most vertebrate animals, including humans. The precursor of vitamin D<sub>3</sub>, 7-dehydrocholesterol is produced in relatively large quantities. 7-Dehydrocholesterol reacts with [[Ultraviolet light#Subtypes|UVB light]] at [[wavelengths]] of 290–315&nbsp;nm. These wavelengths are present in sunlight, as well as in the light emitted by the UV lamps in [[tanning bed]]s (which produce ultraviolet primarily in the [[Ultraviolet light#Subtypes|UVA]] spectrum, but typically produce 4% to 10% of the total UV emissions as UVB, some tanning beds can use only separate UVB light bulbs specifically for vitamin D production). Exposure to light through windows is insufficient because glass almost completely blocks UVB light.</div>FuzzyBot