Role and Balance

Table 1: The role of calcium in the body
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.

Calcium Metabolism

Role and Balance