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NBME 20 Answers

nbme20/Block 1/Question#46

A 55-year-old woman comes to the physician for a ...

Cholecalciferol

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submitted by hayayah(422),

Notice, the stem says "precorsors in the skin"

D3 (cholecalciferol) from exposure of skin (stratum basale) to sun, ingestion of fish, milk, plants.

D2 (ergocalciferol) from ingestion of plants, fungi, yeasts.

Both converted to 25-OH D3 (storage form) in liver and to the active form 1,25-(OH)2 D3 (calcitriol) in kidney.

sympathetikey  C is the 3rd letter in the alphabet. Hence, D3 = Cholecalciferol +  
karljeon  Thanks for the explanation. The question stem made it sound like "what future step will be decreased?" Actual question: "Decreased production of which... is most LIKELY TO OCCUR in this patient?" Maybe NBME needs a grammar Nazi working for them. +2