Answer
The extracellular matrix of bone is made up of inorganic salts and proteins, plus other organic substances and water. The inorganic material is mainly hydroxyapatite, a very hard crystalized material composed mainly of salts of calcium with citrate, carbonate, fluoride and hydroxide. It is this component of the extracellular matric that is responsible for the hardness ( and sometime brittleness) of bone.
The organic contribution to bone extracellular matrix is mainly collagen (fibers) --plus proteoglycans, and minor proteins like osteocalcin and osteopontin. These organic substances in bone account for about 30 % of its mass. This is the component that is responsible for giving bone its tensile strength and its small degree of flexibility.
Work Step by Step
Compact bone has low compressibility; cancellous bone is more compressible.
The tensile strength of a material is basically the maximum load or tension it can bear without breaking (fracture) or failing.
