Medical-Surgical Endocrine Practice Test 2026 – Complete Exam Prep Resource

Serum calcium homeostasis is the primary role of the parathyroid glands. When calcium levels fall, parathyroid hormone is released and orchestrates several effects to raise calcium back toward normal: it stimulates bone resorption to release calcium into the bloodstream, increases calcium reabsorption in the kidney’s distal tubules, promotes phosphate excretion, and boosts production of active vitamin D (calcitriol) in the kidney, which in turn enhances intestinal calcium absorption. This coordinated action specifically targets calcium balance, unlike regulation of potassium or sodium (which involve different renal and hormonal pathways) or the thyroid gland (a separate endocrine organ).