KS3 · Biology

Asthma and the lungs

Imagine breathing through a thin drinking straw. With asthma, something like that happens inside the chest, and the effect travels all the way to your muscles.

Build the chain

From a narrow tube to a tired body

Here are seven things that can happen in a person with asthma. Draw arrows to show what leads to what: start at the airway walls and follow the air. Then check your chain against ours. Which link did you skip?

  1. Airway walls become inflamed and thickened
  2. Bronchial tubes narrow and tighten, so the lumen is smaller
  3. Less air passes through into the lungs
  4. Less oxygen taken in
  5. Less carbon dioxide removed
  6. Less energy available from cellular respiration
  7. Tiredness and lower sporting ability (outcome)
Add a link

No links yet.

Predict, then check

Day to day, asthma symptoms include wheezing, coughing, breathlessness (shortness of breath) and a tight chest. Now think about an asthma attack.

What do you think makes an asthma attack different from everyday asthma symptoms?

Sort it out

Raises the chance, or helps control it?

Tap an item, then tap where it belongs. Watch out for the two that both mention smoking.

Still to sort

Risk factor: increases the chance of having asthma (0)

Things about a person's background, family or early life.

Where the line is: These are about who is more likely to HAVE asthma, not about managing it.

Helps someone with asthma control their symptoms (0)

Things a person who already has asthma can do.

Where the line is: These don't change whether someone has asthma. They help keep the symptoms under control.

9 of 9 still to sort.

Nobody fully understands exactly what causes asthma. But some things make it more likely, and some things help people who have it.

Watch out: A risk factor increases the chance of having asthma; it does not decide it. A person may have one risk factor, several, or none that they know of.

Two kinds of inhaler

Reliever inhalervsPreventer inhaler

This is how asthma is usually controlled, in general. It's biology, not advice for any one person.

Focus

Its main job

Reliever inhaler

Relieves symptoms by relaxing the muscles in the airway walls, opening the airways

Preventer inhaler

Stops symptoms from happening in the first place

The insight

This is the difference people mix up: one eases symptoms, the other is there to prevent them. The clue is in the names. And remember the tightened airways from the chain? Relaxing those muscles lets them open up again.

When it's used

Reliever inhaler

When symptoms need relieving

Preventer inhaler

When attacks are frequent

How the medicine gets in

Reliever inhaler

An aerosol, breathed in, that reaches the airways

Preventer inhaler

An aerosol, breathed in, that reaches the airways

What do you really think?

Can asthma go away?

A Year 9 student says: 'My cousin had really bad asthma when she was little, but now she's 15 and hardly ever needs her inhaler.'

Which of these is closest to what you think right now?
How sure are you?

WHAT YOU'VE LEARNED

A quick recap of today's lesson.

How a narrower tube in your chest can end up as tired muscles.

What you need to know

  • Asthma is a common non-infectious disease that affects the gas exchange (respiratory) system and can cause breathing difficulties. It is not a chronic obstructive pulmonary disease (COPD).
  • The windpipe (trachea) branches into the bronchi, which lead into each lung. In asthma the airway walls become inflamed and thickened, and the airways narrow and tighten, so the lumen is smaller and less air can pass through.
  • Less air in means a person may not take in enough oxygen for cellular respiration or remove enough carbon dioxide, so less energy is available. Poorly managed asthma may cause tiredness and lower sporting ability.
  • Symptoms are wheezing, coughing, breathlessness and a tight chest, and can feel worse during a chest infection. An asthma attack is a sudden, temporary worsening; it is serious, can be life-threatening, and needs medical help straight away.
  • The exact cause isn't fully understood. Risk factors that increase the chance of having asthma: an allergy (like hay fever or a food allergy), family history, low birth weight, lung infections as a child, exposure to smoke or air pollution as a child, and the mother smoking during pregnancy.
  • There is no cure; asthma lasts a lifetime. It is usually controlled with inhalers (relievers open the airways; preventers stop symptoms when attacks are frequent), and people can help control symptoms by not smoking, exercising regularly and having a flu vaccination each year.

The big picture

Asthma is a common non-infectious disease of the gas exchange (respiratory) system. The airway walls become inflamed and thickened and the airways narrow, so less air gets into the lungs. That can mean less oxygen for cellular respiration, less carbon dioxide removed and less energy available. Symptoms include wheezing, coughing, breathlessness and a tight chest; an asthma attack is a sudden, serious worsening that needs medical help straight away. There is no cure, but inhalers and other measures help control it.

Key points

1Asthma narrows the airways: inflamed, thickened walls and a smaller lumen let less air through.
2Less air can mean less oxygen for respiration and less carbon dioxide removed, so less energy is available.
3An asthma attack is a sudden, temporary worsening of symptoms. It is serious and needs medical help straight away.
4Risk factors increase the chance of having asthma; the exact cause is not fully understood.
5Reliever inhalers open the airways by relaxing airway-wall muscles; preventer inhalers stop symptoms happening.
6Asthma is non-infectious and lifelong. Symptoms can improve in adolescence, but people don't grow out of it.

Worked example

Problem

A student writes: 'Asthma makes your airways narrow, so you get tired.' The idea is right, but the links in the middle are missing. Improve the explanation.

⚠ Watch out

Jumping straight from 'the airways narrow' to 'they can't breathe' or 'they get tired'. The real understanding is in the links in between: less air through a smaller lumen, less oxygen for cellular respiration, and less energy available.

🧠

Memory hook

Narrow tube, less air, less oxygen, less energy. A problem in the chest shows up as tired muscles.

✓

Check yourself

Cover the page: what is the difference between a reliever and a preventer inhaler? And why do some people wrongly think you grow out of asthma?

Flashcards

(15)
Is asthma infectious?
No. Asthma is a non-infectious disease, so you can't catch it from someone.
Which body system does asthma affect?
The gas exchange (respiratory) system.
Is asthma a type of COPD?
No. Asthma is not a chronic obstructive pulmonary disease (COPD).
Name the four main symptoms of asthma.
Wheezing, coughing, breathlessness (shortness of breath) and a tight chest.
When can asthma symptoms feel worse?
During a chest infection.
What happens to the airway walls in asthma?
They become inflamed and thickened, and the airways narrow and tighten.
What is the lumen, and what happens to it in asthma?
The hollow space inside an airway. In asthma it gets smaller, so less air can pass through.
Why does less air reaching the lungs matter for energy?
Less oxygen is taken in for cellular respiration, so less energy is available.
Apart from taking in oxygen, what else can narrowed airways make harder?
Removing carbon dioxide.
What is an asthma attack?
A sudden, temporary worsening of symptoms: the airways narrow, airflow is reduced and breathing becomes very difficult. It needs medical help straight away.
Is the exact cause of asthma known?
No, it isn't fully understood. Risk factors increase the chance of having it.
Name three risk factors for asthma.
Any three of: an allergy (such as hay fever), family history, low birth weight, lung infections as a child, smoke or air pollution as a child, the mother smoking during pregnancy.
Reliever inhaler or preventer inhaler: which one relaxes the airway-wall muscles?
The reliever. Relaxing those muscles opens the airways.
Why are people with asthma encouraged to have a flu vaccination each year?
Because flu affects the gas exchange system.
Do people grow out of asthma?
No. There's no cure and it lasts a lifetime. Symptoms can improve in adolescence and may worsen again in old age.

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.

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How this lesson was checked. This KS3 Biologylesson was published through Lightbulb Learning's human-designed editorial process — the educational standards, accuracy rules and publication checks it must pass were authored and approved by Philip Halpin. It passed subject-specific assessment, automated educational checks and technical publication verification before going live (publication checks completed 30 September 2026). Published pages are monitored, human spot-checking is ongoing across the lesson library, and anything found wrong is corrected or withdrawn. How our lessons are made and checked. Spotted a mistake? Email hello@lightbulblearning.co and we'll review it.