Notes

Cambridge Primary Stage 4 Science Notes – Structure and Function

Biology – Life Processes

1-Stage_4_Science_Structure_and_Function_Notes

SMART EXAM RESOURCES

STAGE 4 SCIENCE (BIOLOGY)

Stage 4 Science — Structure and Function (4Bs)

Learning Objectives

By the end of this topic, learners should be able to:

  • Identify major bones in the human body.

  • Explain how muscles and bones work together to produce movement.

  • Describe the main functions of the skeleton.

  • Recognise

    that some animals have an exoskeleton.

  • Distinguish between vertebrates and invertebrates.

4Bs.01 – Important Bones in the Human Body

  • The human skeleton has over 206

    bones .

  • These

    bones give

    the body shape and support.

  • Some key bones include:

Diagram:

Science notes illustration

Region

Important Bones

Function

Head

Skull (cranium), Jaw (mandible)

Protects the brain; helps chewing and speaking.

Chest

Rib cage

Protects the heart and lungs.

Spine

Vertebrae

Protects spinal cord and keeps body upright.

Arms

Humerus, Radius, Ulna

Allow bending, lifting, and rotating.

Legs

Femur, Tibia, Fibula

Support body weight and enable walking/running.

Hips

Pelvis

Supports organs and connects legs to spine.

4Bs.02 – How Bones Move

Bones cannot move by themselves. Muscles are attached to bones with tendons. Muscles work in pairs (antagonistic pairs) — when one contracts, the other relaxes.

Science notes illustration

Example – Arm movement:- To bend your arm, the biceps contracts and the triceps relaxes.- To straighten your arm, the triceps contracts and the biceps relaxes.

4Bs.03 – Functions of the Skeleton

The skeleton performs three vital functions:

Science notes illustration

1. Protection – shields organs such as the brain, heart, and lungs.

2. Support and Shape – keeps the body upright and gives shape.

3. Movement – bones and muscles work together to move the body.

4Bs.04 – Animals with Exoskeletons

Science notes illustration

  • Some animals have skeletons outside their bodies called exoskeletons.

  • These are made of hard materials such as chitin or calcium carbonate and provide protection, support, and prevent water loss.

  • Examples: insects (ants, beetles), crabs, lobsters, spiders.

4Bs.05 – Vertebrates and Invertebrates

Vertebrates have a backbone, while invertebrates do not.

Vertebrates

Invertebrates

Fish, amphibians, reptiles, birds, mammals

Insects, worms, jellyfish, crabs, snails

Internal skeleton (endoskeleton)

May have exoskeleton or none

Backbone protects spinal cord

No backbone present

Summary Checklist

• Name major bones (skull, ribs, spine, pelvis, arms, legs)• Explain how muscles contract and relax to move bones• List the main skeleton functions•

Recognise

what an exoskeleton is and give examples• Classify animals as vertebrate or invertebrate

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