Urinary System


How do kidneys help vitamin D be available for bone growth?

The kidneys turn vitamin D into an active hormone called calcitrol, which helps bones absorb the right amount of calcium from blood. If the kidneys are impaired, bones do not get enough calcium, either because the kidneys fail to turn vitamin D into calcitrol or because they allow too much phosphorus to build up in the blood. The excess phosphorus draws calcium into the blood and blocks it from getting to the bones.


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