Blood calcium must stay near 9–10 mg/dL. Your nerves, muscles, and blood clotting depend on it. Two hormones guard it. PTH raises it, and calcitonin lowers it. Knock it off balance and watch the right one respond.
9.5mg/dL blood Ca²⁺Normal
For example, a low-calcium diet or pregnancy, vs. taking in a lot of calcium at once
Blood calciumkept near the set point
📷 Reference image
A real labeled picture to compare with the interactive above.
Calcium Homeostasis — OpenStax, CC BY 3.0 (via Wikimedia Commons)
