Bone and tooth formation, muscle contraction, heartbeat, blood clotting and nerve impulse.
Great sources for Calcium are:
Kelp, cheese, kale, almonds, yogurt, milk, broccoli and soy
What are some signs that you maybe deficient?
Insomnia and muscle and leg crams
Normallly there are no signs of toxic effect with large doses, some research shows people with kidney stones should avoid high doses
Optimal intake is 1000 to 15000 mg daily