What the Skeleton Does – Human Skeleton (Primary 4 Science and Elementary Technology) | Ganzaa

Human Skeleton

Lessons

Primary 4 · Science and Elementary Technology

Human Skeleton

4 lessons

Lesson 2 of 4

What the Skeleton Does

12 min

Let's begin

Keza helps her uncle put up a tent for a family ceremony. First they set up the poles; then the cloth goes over them. "Without the poles," says her uncle, "the tent would just be a heap of cloth on the ground." Your body has "poles" too: your bones!

Five jobs of the skeleton

Support and shape. The skeleton holds your body up and gives it its shape, like the poles of a tent. Without bones you would be a floppy heap on the floor.
Protection. Hard bones guard the soft parts inside you:
- the skull protects the brain;
- the ribcage protects the heart and lungs;
- the backbone protects the spinal cord, the bundle of nerves running down your back;
- the pelvis protects the organs in your lower belly.
Movement. Muscles are fixed to bones by strong cords called tendons. When a muscle pulls on a bone, the bone moves at a joint. Bones and muscles work together.
Making blood. Inside big bones is a soft, jelly-like part called bone marrow. It makes red blood cells.
Storing minerals. Bones store minerals such as calcium, which the body can use when it needs them.

Tip

The skeleton is a Frame, a Shield, a Lever, a Factory and a Bank: it holds you up, protects you, helps you move, makes blood and stores minerals.

✦

Try it yourself

Try each one first, then tap Show answer to check.

Which bone protects the brain?

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Answer: The skull.

Which part of the skeleton protects the heart and lungs?

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Answer: The ribcage.

Where are red blood cells made?

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Answer: In the bone marrow, inside big bones.

How do bones help you move?

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Answer: Muscles are fixed to bones by tendons; when muscles pull, the bones move at the joints.

Why is your skeleton like the poles of a tent?

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Answer: It holds the body up and gives it its shape.

Quick check

Match each part of the skeleton to what it protects.

Tap one on the left, then its partner on the right.

What you learned today

The skeleton supports the body and gives it shape.
It protects the brain (skull), heart and lungs (ribcage) and spinal cord (backbone).
It lets us move with our muscles, makes blood in the bone marrow and stores minerals such as calcium.

Sources and credits

Human skeleton, by Simple English Wikipedia contributors, Simple English Wikipedia, CC BY-SA 4.0, adapted by Ganzaa.
Bone, by Simple English Wikipedia contributors, Simple English Wikipedia, CC BY-SA 4.0, adapted by Ganzaa.
Natural Sciences Grade 9, Chapter 2: Systems in the human body (the musculoskeletal system), by Siyavula Education, Siyavula, CC BY 3.0, adapted by Ganzaa.

The exercises (Try it yourself and the practice questions) are written by Ganzaa.

This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.

1Five jobs of the skeleton

Try it yourself

Five jobs of the skeleton