Our Bones

Our skeleton is made of 206 bones, the skeletons job is to 1) protect

2) Shape our body (without

It we would be a big blob of

Muscle, skin and more)

3) Support us

4) Protection

5) And allows our movement

The skeleton is divided into two parts; the first part is called the central or axel skeleton it consists of the skull, backbone and ribs and the other part is called the appendiclar skeleton which is the arms and legs.

BONE STRENGTH

Size, shape and strength depend on how it supports the body and the muscles around it.

Bones are stiff because they contain calcium and phosphate. But they also contain fibres collagen (our bodies protein) which makes us slightly flexible so that we can bend slightly under stress rather than crack.

INSIDE THE BONE

Bones are light yellow and have blood vessels and nerves. They are combination of living cells and minerals. Bone cells (called osteocytes) produce rod-like structures of bone minerals called osteons. Most bones have strong outer layers (compact bone) with the osteons packed together, inside this there is a layer of spongy (or cancellous) bone

BONE MARROW

In the middle of the bones there is a jelly-like marrow. This makes new blood cells every second. All of babies bones contain marrow but it goes away by adulthood. But it stays in the breast bone, backbone, ribs and skull.

CARTILAGE

Cartilage is a type of dense connective tissue. Cartilage makes up virtually the entire skeleton in the osteichthyes.