Source: https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/2-2-1-skeletons-and-muscles

[Revision notes](https://senecalearning.com/en-gb/revision-notes.md) › [Primary](https://senecalearning.com/en-gb/revision-notes/primary.md) › [Science](https://senecalearning.com/en-gb/revision-notes/primary/science.md) › [Science: Year 3 & 4 National Curriculum](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum.md) › Skeletons & Muscles

# Skeletons & Muscles

Science: Year 3 & 4 National Curriculum, topic 2.2.1

## Skeletons and Muscles

Animals that have bones inside their bodies are called 'vertebrates'. The bones in the body of an animal form the animal's 'skeleton'.

### Bones for support

![Bones for support](https://image-v2.cdn.app.senecalearning.com/2019-05/f5718ad4-783c-4381-bd7b-a6560a64a7f9/bones-.png)

- Bones are used to help hold our bodies up.
 - Long bones in our legs help us to stand.
 - A set of small bones in the spine (backbone), help to hold up our body.
 - Think of other places where we have bones that support our body.

### Bones for protection

![Bones for protection](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/1.2.1%20Chromosomes%20and%20mitosis/bone-316228_640.jpg)

- Our internal organs are soft and could be easily damaged if they didn't have protection.
- Bones are made of a hard material.
- Bones help to protect some organs.

### Bones for protection examples

![Bones for protection examples](https://image-v2.cdn.app.senecalearning.com/2018-10/f9ddfa09-7f3d-4ae6-bbf1-302ed42c2be5/skull-dead-.jpg)

- The skull protects the brain.
- The ribs protect the lungs.
- The sternum (breast bone) protects the heart.

### Bones can be broken

![Bones can be broken](https://image-v2.cdn.app.senecalearning.com/2019-10/9bbbc02c-330d-4d00-8a10-167b91e0509f/fracture-bone-2333164_1920.jpg)

- Bones can still be broken if there is a strong enough force.
 - When bones break, they can repair themselves.
- Children have bendier bones than adults.

## Bones for Movement

The bones of the skeleton give support and protection and help animals to use their muscles to move.

### Bones for movement

![Bones for movement](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/OCR%20Gateway/3.1.2/muscle%20man.jpg)

- Animals use their muscles to move.
- In vertebrates (animals with backbones), muscles are attached to bones.
 - Attached means stuck on to.

### Pairs of muscles

![Pairs of muscles](https://image-v2.cdn.app.senecalearning.com/courseImages/chemistry/1.1.4%20-%20Metals/muscles-811479_640-min-min.jpg)

- Pairs of muscles in our arms and legs help us to move them.
 - The muscles contract (shorten) and pull the bone.
 - Muscles contracting makes bones move.
 - The bone needs to be part of a joint to be able to move.

### Movement example

![Movement example](https://image-v2.cdn.app.senecalearning.com/2019-08/cfa75102-4ef6-429b-9ee0-3736d684fbf6/worried-girl-413690_1920.jpg)

- Sit on a chair and lift your foot off the ground in front of you by straightening your leg at the knee.
 - The muscle in your thigh (top part of your leg) is contracting.
 - The muscle pulls the shin bone below the knee and makes your leg straighten.
 - The knee is a joint.

### Joints

![Joints](https://image-v2.cdn.app.senecalearning.com/2019-10/697ece26-2921-41b9-8b11-74cf2e331c94/arthrocalman-2384254_1920.jpg)

- The knee is a joint.
- A joint is where two bones come together but can move.
 - The elbow, hip and shoulder are all joints.
- If you put your hand on your thigh muscle when you bend and straighten your leg, you can feel it contracting and relaxing.

### Strengthening muscles

![Strengthening muscles](https://image-v2.cdn.app.senecalearning.com/2019-08/15eb635d-d1ea-42af-9317-38ed1d0bf17e/adventure-athlete-daylight-235922.jpg)

- Exercise helps to build up muscle strength.
- A lack of exercise makes our muscles weak.

## Test yourself on Skeletons & Muscles

- Which of these is true about bones?
- What are bones needed for in our bodies?
- When you are sat on a chair and you straighten your leg, which muscle contracts?
- What is a joint?

[Practise this topic for free](https://app.senecalearning.com/classroom/course/387be3cf-f0c3-401f-9de4-e8658803ed6d/section/42bb4269-994c-463c-a5c5-d13524559a91/session)

- Previous topic: [2.1.8 Junk Food](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/2-1-8-junk-food.md)
- Next topic: [2.2.2 Healthy Bones](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/2-2-2-healthy-bones.md)

## Science: Year 3 & 4 National Curriculum contents

### 1 Year 3: Plants
- 1.1 Types of Plants
  - [1.1.1 Flowering & Non-flowering Plants](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/1-1-1-flowering-and-non-flowering-plants.md)
- 1.2 Parts of a Plant
  - [1.2.1 Roots](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/1-2-1-roots.md)
  - [1.2.2 What do Roots do?](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/1-2-2-what-do-roots-do.md)
  - [1.2.3 Stem](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/1-2-3-stem.md)
  - [1.2.4 Leaves](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/1-2-4-leaves.md)
  - [1.2.5 How Leaves Make Food](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/1-2-5-how-leaves-make-food.md)
  - [1.2.6 Flowers](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/1-2-6-flowers.md)
- 1.3 Pollination
  - [1.3.1 Pollination](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/1-3-1-pollination.md)
  - [1.3.2 Pollination by Insects](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/1-3-2-pollination-by-insects.md)
  - [1.3.3 Pollination by the Wind](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/1-3-3-pollination-by-the-wind.md)
- 1.4 Seeds
  - [1.4.1 Types of Seeds](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/1-4-1-types-of-seeds.md)
  - [1.4.2 Dispersing Seeds](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/1-4-2-dispersing-seeds.md)

### 2 Year 3: Animals (Including Humans)
- 2.1 Food
  - [2.1.1 The Need for Food](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/2-1-1-the-need-for-food.md)
  - [2.1.2 Food Groups](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/2-1-2-food-groups.md)
  - [2.1.3 Carbohydrates](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/2-1-3-carbohydrates.md)
  - [2.1.4 Proteins](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/2-1-4-proteins.md)
  - [2.1.5 Dairy](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/2-1-5-dairy.md)
  - [2.1.6 Fruit & Vegetables](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/2-1-6-fruit-and-vegetables.md)
  - [2.1.7 Fats](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/2-1-7-fats.md)
  - [2.1.8 Junk Food](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/2-1-8-junk-food.md)
- 2.2 Skeletons & Muscles
  - [2.2.1 Skeletons & Muscles](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/2-2-1-skeletons-and-muscles.md)
  - [2.2.2 Healthy Bones](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/2-2-2-healthy-bones.md)

### 3 Year 3: Rocks
- 3.1 Rocks on Earth
  - [3.1.1 Rocks](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/3-1-1-rocks.md)
  - [3.1.2 Fossils](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/3-1-2-fossils.md)

### 4 Year 3: Light
- 4.1 What is Light?
  - [4.1.1 Light as Energy](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/4-1-1-light-as-energy.md)
  - [4.1.2 Reflections](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/4-1-2-reflections.md)
  - [4.1.3 Sunlight](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/4-1-3-sunlight.md)
  - [4.1.4 Shadows](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/4-1-4-shadows.md)

### 5 Year 3: Forces & Magnets
- 5.1 Forces
  - [5.1.1 What is a Force?](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/5-1-1-what-is-a-force.md)
  - [5.1.2 Contact & Non-Contact Forces](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/5-1-2-contact-and-non-contact-forces.md)
  - [5.1.3 Testing Magnetic Materials](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/5-1-3-testing-magnetic-materials.md)
  - [5.1.4 Attracting & Repelling Magnets](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/5-1-4-attracting-and-repelling-magnets.md)
  - [5.1.5 Uses of Magnets](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/5-1-5-uses-of-magnets.md)

### 6 Year 4: Living Things & Their Habitats
- 6.1 Grouping Animals
  - [6.1.1 Biodiversity & Classification](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-1-1-biodiversity-and-classification.md)
  - [6.1.2 Grouping Animals](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-1-2-grouping-animals.md)
- 6.2 Vertebrates
  - [6.2.1 Vertebrates](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-2-1-vertebrates.md)
  - [6.2.2 Mammals](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-2-2-mammals.md)
  - [6.2.3 Reptiles](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-2-3-reptiles.md)
  - [6.2.4 Fish](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-2-4-fish.md)
  - [6.2.5 Amphibians](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-2-5-amphibians.md)
  - [6.2.6 Birds](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-2-6-birds.md)
- 6.3 Invertebrates
  - [6.3.1 Invertebrates](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-3-1-invertebrates.md)
  - [6.3.2 Insects](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-3-2-insects.md)
  - [6.3.3 Spiders](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-3-3-spiders.md)
  - [6.3.4 Slugs & Snails](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-3-4-slugs-and-snails.md)
  - [6.3.5 Worms](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-3-5-worms.md)
- 6.4 Grouping Plants
  - [6.4.1 Grouping Plants](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-4-1-grouping-plants.md)
  - [6.4.2 Flowering Plants](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-4-2-flowering-plants.md)
  - [6.4.3 Non-Flowering Plants](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-4-3-non-flowering-plants.md)
- 6.5 Classification Keys
  - [6.5.1 Classification Keys](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-5-1-classification-keys.md)
- 6.6 Environmental Change
  - [6.6.1 Positive Impact of Humans on the Environment](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-6-1-positive-impact-of-humans-on-the-environment.md)
  - [6.6.2 Negative Impact of Humans: Deforestation](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-6-2-negative-impact-of-humans-deforestation.md)
  - [6.6.3 Negative Impact of Humans: Litter](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-6-3-negative-impact-of-humans-litter.md)
  - [6.6.4 Negative Impact of Humans: Overpopulation](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/6-6-4-negative-impact-of-humans-overpopulation.md)

### 7 Year 4: Animals, Including Humans
- 7.1 Teeth
  - [7.1.1 Why Do We Need Teeth?](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-1-1-why-do-we-need-teeth.md)
  - [7.1.2 'Baby' Teeth](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-1-2-baby-teeth.md)
  - [7.1.3 Adult Teeth](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-1-3-adult-teeth.md)
  - [7.1.4 Incisors](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-1-4-incisors.md)
  - [7.1.5 Canines](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-1-5-canines.md)
  - [7.1.6 Premolars](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-1-6-premolars.md)
  - [7.1.7 Molars](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-1-7-molars.md)
- 7.2 Digestion
  - [7.2.1 What is Digestion?](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-2-1-what-is-digestion.md)
  - [7.2.2 The Digestive System - The Mouth](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-2-2-the-digestive-system-the-mouth.md)
  - [7.2.3 The Digestive System - The Stomach](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-2-3-the-digestive-system-the-stomach.md)
  - [7.2.4 The Digestive System - The Small Intestines](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-2-4-the-digestive-system-the-small-intestines.md)
  - [7.2.5 The Digestive System - The Large Intestines](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-2-5-the-digestive-system-the-large-intestines.md)
- 7.3 Food Chains
  - [7.3.1 What are Food Chains?](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-3-1-what-are-food-chains.md)
  - [7.3.2 Producers, Predators & Prey](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-3-2-producers-predators-and-prey.md)
  - [7.3.3 Herbivores & Carnivores](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/7-3-3-herbivores-and-carnivores.md)

### 8 Year 4: States of Matter
- 8.1 The 3 States of Matter
  - [8.1.1 States of Matter](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/8-1-1-states-of-matter.md)
  - [8.1.2 Changes of State](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/8-1-2-changes-of-state.md)
- 8.2 The Water Cycle
  - [8.2.1 The Water Cycle](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/8-2-1-the-water-cycle.md)
  - [8.2.2 Evaporation at Different Temperatures](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/8-2-2-evaporation-at-different-temperatures.md)

### 9 Year 4: Sound
- 9.1 How Do I Hear?
  - [9.1.1 What is Sound?](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/9-1-1-what-is-sound.md)
  - [9.1.2 Sound Travels to Your Ear](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/9-1-2-sound-travels-to-your-ear.md)
- 9.2 Pitch
  - [9.2.1 Pitch](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/9-2-1-pitch.md)
- 9.3 Volume
  - [9.3.1 Volume](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/9-3-1-volume.md)
  - [9.3.2 How Distance Affect Volume](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/9-3-2-how-distance-affect-volume.md)

### 10 Year 4: Electricity
- 10.1 Uses of Electricity
  - [10.1.1 What Uses Electricity?](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/10-1-1-what-uses-electricity.md)
- 10.2 Conductors & Insulators
  - [10.2.1 Electrical Conductors](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/10-2-1-electrical-conductors.md)
  - [10.2.2 Electrical Insulators](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/10-2-2-electrical-insulators.md)
- 10.3 Making Circuits
  - [10.3.1 What is a Circuit?](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/10-3-1-what-is-a-circuit.md)
  - [10.3.2 Complete Circuits](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/10-3-2-complete-circuits.md)
  - [10.3.3 Electrical Safety](https://senecalearning.com/en-gb/revision-notes/primary/science/science-year-3-and-4-national-curriculum/10-3-3-electrical-safety.md)