


5 of 8

Asthma

Picture 10. Asthma - an allergic reaction.
Open the animation in a new window.

Biology of an Asthma attack
	As you may have seen in The human immune system, triggers like pollen, house dust, pet hairs or just the weather can cause an asthma attack. The trigger causes cells lining the bronchioles to release chemicals called histamine. This is similar to when a person suffers hayfever but is more serious as it happens in the bronchioles.

The histamine causes cells in the wall of the airways to be come inflammed, release large amounts of mucus and swell. It also stimulates muscles that line the airway wall to contract. The overall effect is that the airway narrows and dangerously limits the flow of air into and out of the lungs.

Measuring asthma

Doctors can measure the effects of asthma and restricted airways using an instrument called a vitalograph. The patient being tested breathes out as quickly as they can through a mouthpiece. A trace makes a graph of the amount of air they breathe out and how quickly they can do it. A healthy person will be able to exhale over 75% of their total lung volume in less than one second. This reading is called the Forced Expiratory Volume in one second (FEV1). A person suffering from asthma, or some other lung problem, will not be able to achieve this. Their FEV1 will be reduced. Measurement like this allow doctors to modify tailor the treatment of a patient to its most efficient.

Picture 11. The results show a healthy person breathes more easily than someone with asthma.

Picture 11. Klara enjoying a normal holiday.

What is asthma like?

Klara is 16 years old and is studying for her GCSE's. This interview with her will give you some idea of what it's like to have asthma.

How long have you had asthma?
I had my first asthma attack when I was 4, my mum thought I had a chest infection, I was coughing so much, so she took me to the doctor. I've had it ever since then.

What does it feel like to have an asthma attack?
My chest feels tight and it is difficult to breathe. You never get used to that breathless feeling and I sometimes start to panic. When that happens I know I have to use my inhaler straight away.

What does the inhaler do?
It helps me breathe more easily. During an attack the airways in the lung narrow making it difficult to take a breath, the inhaler relaxes them, and I can breathe more easily.

Picture 12. Klara using her inhaler.

What would happen if you didn't use your inhaler?
That's happened to me once. I'd left my inhaler in the changing room when we were doing PE on the field. I felt breathless and really panicky. I couldn't go back to get it from the changing room as I felt so shaky.

What happened then?
The teacher made me sit, calm down and take regular deep breaths. I had started to feel quite light headed, like I was going to faint. My friend got my inhaler and after I had taken it I started to feel better.

Are there any things that trigger an attack?
With me it seems to be when it is cold weather, especially when I have been running. With other people it can be pollen, cigarette smoke or deodorant aerosols. I know someone who gets attacks when she gets stressed out. Loads of different things can trigger them, you have to learn to avoid what causes them, or make sure you use your inhaler first.

Do you take anything to stop you getting attacks?
I have another inhaler, a brown, steroid one, which I have to use every day. It's called a 'preventer' it stops things irritating my lungs and triggering an attack.

How big a problem is your asthma?
I'm lucky, my asthma is quite mild, some people I know have to have regular check ups and sometimes even have to go into hospital. So long as I recognise the first signs of an attack and use my inhaler then, I am usually OK.

Asthma facts in the UK
•	5.1 million people suffer from asthma.
•	About 1,500 people die from asthma each year. Up to 90% of these deaths could be prevented.
•	1 in 8 children under the age of 16 has asthma.
•	Every 16 minutes a child is admitted to hospital because of their asthma.
•	Children whose parents smoke are 1.5 times more likely to develop asthma.
•	Treating asthma costs the National health Service £850 million per year.
Figures from the National Asthma Campaign

Question 4

Look at the statements below and choose the best response in each case.

a)	What kind of things can trigger an asthma attack?

	Pollen
	Pet hairs
	Stress
	All of the above answers


b)	What happens in the lungs during an asthma attack?

	Airways dilate and this makes it difficult to breath.
	Airways narrow. This makes breathing difficult.
	The diaphragm does not contract.
	Membranes covering the lungs constrict.


c)	How do salbutamol, or Ventolin, inhalers work?

	They clear mucus from the mouth.
	They relax the diaphragm.
	They relax the intercostal muscles.
	They relax muscles in the bronchiole walls.


d)	How do preventers work ?

	They relax the muscles in the bronchiole walls.
	They help to make the bronchioles less sensitive to normal triggers.
	They cover the surface of the bronchioles and stop asthma attacks.
	They dry up the mucus in the bronchioles.