[Campbell Biology P.1060] Which statement accurately describes the roles of Parathyroid Hormo... | Practice Question

Which statement accurately describes the roles of Parathyroid Hormone PTH and Calcitonin in blood calcium regulation?

  • A: Both PTH and Calcitonin increase blood Ca2+ levels.
  • B: PTH is released when blood Ca2+ levels are high, while Calcitonin is released when they are low.
  • C: Calcitonin promotes bone breakdown, while PTH inhibits it.
  • D: PTH increases Ca2+ reabsorption in kidneys, and Calcitonin enhances Ca2+ excretion by kidneys.

Explanation

PTH acts to raise blood Ca2+ by stimulating reabsorption in the kidneys. Calcitonin, conversely, lowers blood Ca2+ by enhancing Ca2+ excretion by the kidneys and inhibiting bone breakdown.