Main mineral salt of bone (AIIMS MAY 2010)
1. The main salt in bone extracellular matrix is hydroxyapatite. This is made up of calcium ions and phosphate ions Ca10(PO4)6(OH)2.
2. Most of the weight of bone is due to its extracellular matrix, and 70% of that weight is due to inorganic salts.
3. Up to fifty percent of bone is made up of a modified form of the inorganic mineral hydroxylapatite (known as bone mineral).
4. Carbonated calcium-deficient hydroxylapatite is the main mineral of which dental enamel and dentin are comprised.
5. Hydroxyapatite crystals are also found in the small calcifications (within the pineal gland and other structures) known as corpora arenacea or 'brain sand'.