KS3 · Biology

The human skeleton

Is your skeleton alive? Most people say no. By the end of this lesson you can prove it is, and say why each bone sits where it does.

Biology · The human skeleton

Your skeleton: what is there, and why

View: The bones. Showing 1 layer: Skeleton

View

Explore

tap a part ↓

This is your skeleton: all the bones in your body, connected together at joints, from the tiny ossicles in your ear to the femur in your thigh. Tap a part to find out why it is there.

Switch between the three views, then tap each part to find out what it does.

Sort it out

Four jobs, one skeleton

Pick a statement, then pick the job it shows the skeleton doing.

Still to sort

Support (0)

holding the body up

Where the line is: Support is about holding the body up. Protection is about guarding something inside.

Protection (0)

guarding organs and tissues

Where the line is: Protection means an organ or tissue is kept safe inside bone. If nothing is being guarded, it is not protection.

Movement (0)

letting the body move and bend

Where the line is: Movement here is about flexibility: the back can bend because the column is made of many small bones.

Making blood cells (0)

what happens inside some bones

Where the line is: This job happens inside the bone, in the marrow, not in the bone’s shape.

7 of 7 still to sort.

The jellyfish is here on purpose: sometimes the clearest way to see a job is to imagine an animal that cannot do it.

Predict, then check

Commit to an answer first. Guessing wrong and finding out why is how this sticks.

Imagine a person whose bone marrow stopped working. What would happen to them?

Big question

Are your bones alive?

Picture the model skeleton in a science lab: pale, dry and hard as stone. It is easy to think the bones inside you are the same.

Which of these is closest to what you think about the bones inside YOU right now?

Bones are dead. They are like a coat hanger that the rest of my body hangs on.Bones are just hard stuff, like rock, so they never change.Bones are alive while you are growing, but once you are fully grown they are dead.Bones are alive. They are made of cells, so they can grow and repair themselves.

How sure are you?

I'm sureI think soI'm guessing

Bones are dead. They are like a coat hanger that the rest of my body hangs on.

This is a common misconception

You are half right: your skeleton really does hold you up. But a coat hanger cannot grow and cannot mend itself when it snaps, and your bones can do both. Bone is a living tissue. A tissue is a group of similar cells working together for the same function, and bone tissue is made of bone cells.

Bones are just hard stuff, like rock, so they never change.

This is a common misconception

Hard, yes. Unchanging, no. Bone tissue is made up of bone cells, and cells can make new cells. That is exactly how your bones get bigger as you grow, and how a broken bone repairs itself.

Bones are alive while you are growing, but once you are fully grown they are dead.

This is a common misconception

Good thinking to link growing with being alive, but growth is not the only clue. Bones can also repair themselves when they break, and that repair is done by bone cells making new cells. That is living tissue at work.

Bones are alive. They are made of cells, so they can grow and repair themselves.

This matches the evidence

Spot on. Bone is a living tissue made of bone cells. Because bones are made of cells, they can make new cells: to grow, and to repair themselves when broken. Next, let us find out what those living cells need to keep going.

Bone is living tissue: bone cells that can make new cells, so bones can grow and repair themselves.

Follow the chain

Reason it through

Why do bones need a rich blood supply?

Link 1 of 3

First link · your turn

Bone is made of living bone cells. What does the blood bring to them?

Locked — reveal the link above first

How a broken bone mends

Step through the repair in order. Notice the soft stage comes before the hard one.

The bone breaksA break splits the bone. But bone is living tissue, so its cells can start making new cells to repair it.

WHAT YOU'VE LEARNED

A quick recap of today's lesson.

Not a dead coat hanger: a living frame that holds you up, guards you, bends and makes your blood cells.

What you need to know

Say what the skeleton is and what a joint is.
Name the smallest bones (the ossicles, in the ear) and the largest bone (the femur, in the thigh).
Name the four functions of the skeleton and give a part of the skeleton that does each one.
Explain how the vertebral column can support you, protect the spinal cord and still let your back bend.
Explain why bone counts as a living tissue, why it needs a rich blood supply, and how a broken bone repairs itself.
Say what red and white blood cells do, and what would happen without working bone marrow.

The big picture

Your skeleton is all your bones, connected at joints (places where two or more bones meet), from the tiny ossicles in your ear to the femur in your thigh. It has four jobs: support (the vertebral column holds you upright), protection (the skull, rib cage and vertebral column guard the brain, the heart and lungs, and the spinal cord), movement (many small vertebrae let your back bend) and making blood cells (in bone marrow). Bone is living tissue made of bone cells. Its rich blood supply lets it grow and repair: a break is joined by cartilage first, then hard bone.

Key points

1The skeleton is all the bones in the body, connected together at joints. A joint is where two or more bones meet.

2Support: the vertebral column holds the body upright. A jellyfish has no bones, so it has no skeleton to hold it up.

3Protection: the skull protects the brain, the rib cage protects the heart and lungs, and the vertebral column protects the spinal cord. The brain and spinal cord make up the central nervous system.

4Movement: the vertebral column is made of many smaller bones called vertebrae, connected together, which gives the back flexibility.

5Making blood cells: bone marrow, a jelly-like substance found mostly in the larger bones of the arms and legs, makes red blood cells (which carry oxygen) and white blood cells (which destroy bacteria and viruses).

6Bone is living tissue made of bone cells. Its rich blood supply brings oxygen and glucose for respiration, and nutrients for growth and repair.

7A broken bone is joined first by cartilage, a softer connective tissue, which is eventually replaced by hard, rigid bone.

.we-_R_18slubsnpfiv5ubrb_ [data-we-step]{display:flex !important}.we-_R_18slubsnpfiv5ubrb_ [data-we-solution]{display:block !important}.we-_R_18slubsnpfiv5ubrb_ [data-we-reveal]{display:none !important}

Worked example

Problem

Aisha says: "The skull and the vertebral column do exactly the same job." Is she right? Use what you know about both to decide.

⚠ Watch out

Mixing up the vertebral column and the spinal cord. The vertebral column (your spine) is the column of bones. The spinal cord runs inside it, and it is part of the central nervous system. The bones protect the cord; they are not the cord.

🧠

Memory hook

Four jobs, one skeleton: "Some People Make Bread". S is for Support, P for Protection, M for Movement, B for making Blood cells. And remember the spine does the first three all by itself.

✓

Check yourself

Cover the page. Which part of the skeleton protects the heart and lungs? Where are blood cells made? And in one sentence: why can a broken bone mend itself?

Flashcards

(14)

What is the human skeleton?

All the bones in the body, connected together at joints.

What is a joint?

A place where two or more bones meet.

Which are the smallest and the largest bones in the body?

Smallest: the ossicles, in the ear. Largest: the femur, in the thigh.

What are the four functions of the skeleton?

Support, protection, movement and making blood cells.

Which part of the skeleton holds the body upright?

The vertebral column (spine).

What do the skull and the rib cage protect?

The skull protects the brain. The rib cage protects the heart and lungs.

What runs inside the vertebral column, and which body system is it part of?

The spinal cord runs inside it. The spinal cord is part of the central nervous system, along with the brain.

Why can your back bend?

The vertebral column is made of many smaller bones (vertebrae) connected together, which gives it flexibility.

What is a tissue?

A group of similar cells working together for the same function.

Why can bones grow and repair themselves?

Bone is a living tissue made of bone cells, and cells can make new cells.

What does the rich blood supply bring to bones, and why?

Oxygen and glucose, which bone cells use in respiration to release energy, plus the nutrients needed for growth and repair.

How does a broken bone mend?

The break is first joined by cartilage, a softer connective tissue, which is eventually replaced by hard, rigid bone.

What is bone marrow, and where is it mostly found?

A jelly-like substance where red and white blood cells are made, found mostly in the larger bones of the arms and legs, such as the femur.

What do red and white blood cells do?

Red blood cells carry oxygen to cells for respiration. White blood cells destroy bacteria and viruses that can make us ill.

Tap any card to flip it, or use Study as deck to go through them one at a time. In the full lesson these run as a spaced-repetition deck — you rate each card Hard, Good or Easy and the tricky ones keep coming back until they stick.

Learning with Lightbulb is opening soon

You can use this lesson now. Join the waitlist and we'll let you know when the full Lightbulb experience is ready.

Keep me posted

Four jobs, one skeleton

Are your bones alive?

More KS3 Biology topics