Composition of bone

The Composition of bone is composed of organic and inorganic matters. Roughly it contains 30% organic and 70% inorganic matter and this proportion varies with the bones in different parts of the body.

The proportion varies with the age and  there is high percentage of organic matter In growing animals, which is slowly replaced by inorganic matter.

Organic matter

Organic matter is present in the bone are bone cells, collagen fibres and matrix or the intercellular substance.

Inorganic matter

The organic matter chiefly consists of the fibrous protein- collagen and ossein and chondroitin sulphate.

The organic part of bone contributes to the flexibility. It consists mostly of calcium phosphate (about 85%), and small amounts of calcium carbonate (10%), magnesium phosphate, sodium carbonate and sodium chloride.

The inorganic salts are responsible for the rigidity and hardness of bone.