Edexcel iGCSE Biology-3.17 Risk Factors for Coronary Heart Disease- Study Notes- New Syllabus
Edexcel iGCSE Biology-3.17 Risk Factors for Coronary Heart Disease- Study Notes- New syllabus
Edexcel iGCSE Biology-3.17 Risk Factors for Coronary Heart Disease- Study Notes -Edexcel iGCSE Biology – per latest Syllabus.
Key Concepts:
3.17 understand how factors may increase the risk of developing coronary heart disease
Coronary Heart Disease (CHD) – Risk Factors
📝 Introduction
Coronary heart disease (CHD): when the coronary arteries (supply heart muscle with oxygenated blood) become narrowed or blocked due to fatty deposits (atherosclerosis).
Reduced blood flow → less oxygen & glucose to heart muscle → chest pain (angina), heart attacks.
⚠️ Main Risk Factors
1. Diet (High in Saturated Fats & Cholesterol)
- Leads to fatty deposits (plaques) in arteries.
- Narrows arteries → reduces blood flow.
2. Smoking
- Nicotine → raises blood pressure.
- Carbon monoxide → reduces oxygen carrying capacity of blood.
- Damages artery walls → faster plaque formation.
3. Lack of Exercise
- Increases risk of obesity.
- Obesity → higher blood pressure & cholesterol → CHD risk rises.
4. High Blood Pressure (Hypertension)
- Extra strain on artery walls.
- More likely to get damaged → plaque buildup increases.
5. Genetics / Family History
- If close relatives had CHD → higher chance of developing it.
6. Age
- Risk increases with age.
- Arteries less elastic → more prone to blockage.
7. Gender
- Men more likely than women (before menopause).
- Oestrogen gives women some protection, but risk rises after menopause.
📊 Summary Table
| Risk Factor | Why it Increases CHD |
|---|---|
| High saturated fat diet | Fatty deposits block arteries |
| Smoking | Nicotine ↑ BP, CO reduces O₂ → damages arteries |
| Lack of exercise | Obesity & high BP risk |
| High blood pressure | Strains artery walls → damage |
| Genetics | Inherited higher risk |
| Age | Arteries less elastic, more plaque risk |
| Gender | Men > women (before menopause) |
⚡ Quick Recap
CHD = narrowed/blocked coronary arteries due to fatty deposits.
Main risks: diet, smoking, lack of exercise, high BP, genetics, age, gender.
All cause less oxygen & glucose to heart → higher heart attack risk.