The bones

A typical healthy adult has over 200 bones in their body. Bones have a number of important functions:

• support the body
• protect internal organs
• are attached to muscles to allow movement
• contain bone marrow, which produces and stores new blood cells
• store proteins, minerals and nutrients, such as calcium.

Bones are made up of different parts, including a hard, outer layer (known as cortical or compact bone) and a spongy inner core (known as trabecular or cancellous bone). The bone marrow is found in this spongy core.

Cartilage is the tough material at the end of each bone that allows one bone to move against another. The meeting point of two bones is called a joint.

Bones have two types of cells – osteoblasts and osteoclasts. Osteoblasts create new bone and osteoclasts break down old bone. Normal bone is constantly going through a process called remodelling, in which old bone is broken down and replaced with new bone.

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