| A | B |
|---|
| How many bones are there in the body? | Over 200. |
| What is the purpose of the skeleton? | To support the body, to protect some of the vital organs of the body and to help the body move. |
| Give an example of how the skeleton supports the body. | Without a backbone we would not be able to stay upright. |
| Give examples of how the skeleton protects the body. | The skull protects the brain, the ribcage protects the heart and lungs, the backbone (spine) protects the spinal cord. |
| How does the skeleton help the body move? | Muscles are used to move the bones that are joined by flexible joints. |
| How are bones in the body joined together? | Some bones in the skeleton are joined rigidly together and cannot move against each other. Bones in the skull are joined like this. Other bones are joined to each other by flexible joints. |
| Give two examples of hinge joints. | Knee and elbow joints. |
| Give two examples of ball and socket joints. | Hip and shoulder joints. |
| What are the main features of a joint? | The bones are covered with cartilage, it is kept slippery by synovial fluid and the bones are joined by tough ligaments. |
| What does the cartialage in a joint do? | It stops the bones wearing away when they rub against each other. |
| What does the synovial fluid in a joint do? | It keeps the joint slippery and helps it to move smoothly. |
| What does the ligaments in a joint do? | They join the two bones in the joint and stop it falling apart. |
| How are the muscles attached to bones? | By strong tendons. |
| How does a muscle move bone? | It gets shorter or contracts. This is called a muscle contraction. |
| Do muscles pull or push? | They can only pull. |
| How do muscles move a joint in both directions if they can only pull? | They work in pairs with opposite actions, called antagonistic muscles. |
| Give an example of antagonistic muscles controlling a joint. | The elbow joint lets our forearm move up or down. It is controlled by two muscles, the biceps on the front of the upper arm, and the triceps on the back of the upper arm, when the biceps muscle contracts, the forearm moves up, when the triceps muscle contracts, the forearm moves down. |
