Biology
Calcium Homeostasis
Quick fact
More than 99% of the body's calcium is stored in bones and teeth, but the tiny fraction in blood is so tightly controlled that a 20% drop can cause muscle spasms and heart arrhythmias.
Why this is interesting
You know calcium builds strong bones, but did you know your body will actually dissolve your skeleton if your blood calcium drops even a tiny bit? How does it decide when to break down bone or build it back up?