Blood calcium must stay near 9–10 mg/dL — it runs your nerves, muscles, and clotting. Two hormones guard it: PTH raises it, calcitonin lowers it. Knock it off and watch the right one respond.
9.5mg/dL blood Ca²⁺Normal
e.g. low-calcium diet / pregnancy vs a big calcium load
Blood calciumheld near the set point
📷 Reference image
A real labeled figure to compare with the interactive above.
Calcium Homeostasis — OpenStax, CC BY 3.0 (via Wikimedia Commons)
