The Job of the skeleton is to:
- Support the body and allow it to move
- Protect your vital organs
Vertebrates are fish, amphibians, reptiles, birds and mammals. They all have a backbone and an internal skeleton.
The advantages of an internal skeleton are:
- It can easily grow with the body
- It's easy to attatch muscles to it
- It's more flexible than an exo-skeleton
Bones are made up of living cells. This means that they grow and can repair themselves.
- are hollow
- are lighter than solid bones of the same mass
- are stronger than solid bones of the same mass
- have more efficient movement than solid bones
- sometimes are filled with bone marrow
Bone marrow is a spongy substance that nakes new blood cells.
Cartilage is living tissue that looks and feels a bit rubbery.
Bones start off as cartilage in the womb.
As you grow the cartilage is replaced by bone.
Ossification is the depositing of calcium and phosphorous in the cartilage which changed it to bone.
To tell if someone if still growing you can look at how much cartilage is present in the body. The more there is the more a person still has to grow.
When you're fully grown there will still be cartilage at the ends of bones.
Damage to bones and cartilage
Bones and cartilage are made of living tissue so can get infected.
Bones are really strong but can be broken (fractured) by a sharp knock.
Elderly people are more prone to broken bones as the suffer from osteoporosis.
Osteoporosis is the loss of calcium from bones making them more brittle, softer and more likely to break.
Broken bones can easily injure nearby tissues. Therefore you shouldn't move anyone who might have a fracture.