Ca2+ exists in the extracellular plasma two states: (1) free ionized state and (2) bound to other molecules (mostly albumin, rest – beta-globulins, phosphate, citrate) ionized Ca2+ concentration is inversely related to pH -> an increase in pH results in a decrease in ionized Ca2+

Hypercalcaemia: Nature: Bones, stones, groans and psychic moans. Usually associated with increased calcium release form bones and impaired renal removal and malignancy