Role and Balance
| Role | Description |
| Metabolic | Coenzyme for coagulation factors |
| Neuromuscular | Muscle excitability and contractionNeurotransmitter release |
| Structural | Bone and teeth |
| Signalling | Intracellular second messenger |
Balance of calcium in the body
The bone pool of Ca2+ of 25,000mmol has a small component that moves between bone and the ECF regulating Ca2+ homeostasis.
Ionised Ca2+ is filtered through the renal glomeruli into the tubules and most is reabsorbed. In the normal state only 2.5-7.5mmol/24h appears in the urine.
Unless lactating, pregnant or growing, the dietary requirement of Ca2+ is 12.5mmol/24h as faecal losses amount to approximately 10mmol/24h.
