Biology / Unit 12 Bio 2941 short lesson, about 20 seconds
Parathyroid Hormone and Calcitonin: Opposing Calcium Control
Captions available
The idea
Parathyroid hormone raises blood calcium by stimulating bone breakdown and kidney and intestinal absorption; calcitonin lowers it by inhibiting bone breakdown, opposing PTH through feedback on each trigger.
In practice
Falling blood calcium triggers PTH release; rising blood calcium triggers calcitonin release.
Where people slip
Calcitonin's role in healthy adults remains poorly defined compared with PTH's, despite a clearer role in children and pregnancy.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Something wrong in this lesson? Flag it · Sources for Biology