BIOLOGY · Stage 8 · Chapter 5: Respiration and the Respiratory System
Biology 5.9 Asthma — Respiratory Conditions and Treatments — Alhussan International Academy - Biology (Stages 7-9) Revision Notes & Topical Questions
5 min read 7 parts Lesson 9 of 12
Lesson summary
Biology 5.9 Asthma — Respiratory Conditions and Treatments — Alhussan International Academy — Biology (Stages 7–9) notes: Describe the causes, symptoms and treatments of asthma, relate them to the structure of the airways and show how scientific understanding developed.Asthma — a…
- Not infectious
- Family and allergy
- Active lives
- Without treatment
- Sensitive airways
- Common triggers
Section 1 of 7What is asthma
- Asthma
- a long-term (chronic) condition of the airways in which they are sensitive and become inflamed and narrow in response to triggers.
- Frequency
- around 8–9% of people worldwide have asthma.
- Not infectious
- it cannot be caught from another person, and it is not usually curable but can be controlled with treatment.
- Family and allergy
- it often runs in families and is more common in people with allergies such as hay fever or eczema.
- Active lives
- many people with asthma, including top sports stars, live healthy, active lives.
Section 2 of 7What happens in an asthma attack
- Breathing
- a person struggles to breathe in and out and cannot get enough oxygen or remove toxic carbon dioxide.
- Muscles
- the muscles around the airways to the lungs contract, making the tubes narrower so it is hard to move air in or out.
- (discovered from 1892)
- the muscles around the airways to the lungs contract, making the tubes narrower so it is hard to move air in or out.
- Lining
- the linings of the bronchi swell and make extra mucus, making breathing even harder.
- (discovered almost 100 years later)
- the linings of the bronchi swell and make extra mucus, making breathing even harder.
- Result
- less air reaches the alveoli, so less oxygen reaches the blood.
- Symptoms:
- wheezing;
- coughing at night which disturbs sleep;
- shortness of breath;
- a tight feeling in the chest;
- difficulty breathing.
- Without treatment
- asthma may make it impossible to run, play or work.
Section 3 of 7Triggers
- Sensitive airways
- people with asthma have very sensitive airways triggered by environmental triggers.
- Common triggers
- pollen, smoking, infections, food allergies, stress, air pollution, exercise, medicines, mould, dust mites, pets and cold air.
- Frequency of attacks
- some people have attacks every day and others only a few times a year.
- Avoidance
- avoiding triggers, for example with allergen-proof bedding and no smoke, helps control asthma.
Section 4 of 7Treatment
| Treatment | How it works | When used |
|---|---|---|
| Reliever inhaler (such as salbutamol) | Relaxes the muscles around the bronchi, so the airways open quickly | During an attack, or before exercise to stop the tubes reacting |
| Preventer inhaler (steroid) | Reduces inflammation, making the airways less sensitive and attacks much less likely | Every day, to prevent attacks |
- Relievers
- they were the first modern asthma medicines.
- Preventers
- they were developed once doctors discovered that the airways also become inflamed in asthma.
- Combination
- using preventers and relievers together lets many people live healthy, active lives.
Section 5 of 7Getting medicines to the lungs
- Problem
- doctors needed to get medicines down to where they are needed, deep in the airways.
- Inhalers
- engineers designed inhalers, medical devices that work with natural breathing to deliver medicine deep into the airways.
- The drug is a fine mist delivered directly to the lungs, so it works fast and a small dose is enough.
- A spacer device helps children and others to breathe in the medicine.
Section 6 of 7Scientific understanding and application
- History
- the Ancient Greeks, Egyptians and Romans described asthma attacks, but doctors began to understand them only in the 1800s.
- Medicines
- effective medicines were not developed until doctors understood the causes.
- Application
- engineers applied scientific knowledge to design inhalers.
Section 7 of 7Other respiratory conditions
- Bronchitis
- inflammation of the bronchi causing a cough with mucus, often from infection or smoking.
- Emphysema
- destruction of the alveoli.
- Lung cancer
- uncontrolled cell growth, strongly linked to smoking.
- Peak flow meter
- it measures how fast a person can blow air out, and is lower in asthma when the airways are narrowed, so daily readings show how well treatment works.
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