Effective & Trusted Medications Guide

Bone has a complex structure that achieves the maximum amount of strength for the least amount of weight.

It can increase its thickness in areas subjected to repeated heavy loads, repair itself when broken and is the site of manufacture of most of the components of blood (the bone marrow).

If you take a typical bone such as the femur (upper leg bone) and cut it across, you will see there is an outer shell of very hard bone. In the middle space it has a honeycomb structure, through which is mingled the bone marrow.

Bone is made up mostly of collagen fibres, upon which are laid down crystals made from calcium and phosphate that give bone its ability to withstand compression and bending forces.

Cells that repair and dissolve bone

If you looked at bone under a microscope, you’d see two types of specialised cells scattered throughout:

o cells that continually make new bone, called osteoblasts.

o cells that continuously dissolve bone into its component materials, called osteoclasts.

Bone is therefore not a static tissue, but is always on the go. The actions of bone manufacture and disassembly are usually exactly balanced.

How bone repairs itself

When increased loads are repeatedly put upon a bone, the osteoblasts become more active, laying down more bone and increasing the strength of the region.

When a bone fractures, osteoblasts go into overdrive around the fracture site, laying down more collagen fibres and minerals on top to strengthen them.