Health and disease (AQA GCSE Biology): Revision Notes
Health and disease
What is health?
Health means being well in your body and mind. It's not just about not being ill. The World Health Organisation defines health as more than just the absence of disease.
Health is the state of physical and mental wellbeing.
Understanding health requires looking at how different aspects of our wellbeing work together to create overall health.
The Three Components of Health:
Health has three main parts that work together:
- Physical wellbeing - eating well, sleeping properly, being free from disease
- Mental wellbeing - how you feel about yourself
- Social wellbeing - how well you get on with other people
All three parts are important. You need all of them to be truly healthy.
Types of disease
Diseases are major causes of ill-health. Understanding the different types helps us learn how they spread and how to prevent them. There are two main types:
Non-communicable diseases
These diseases cannot be passed from person to person. They typically develop over time due to lifestyle factors, genetics, or environmental influences.
Key features of non-communicable diseases:
- Number of cases changes slowly over time
- Cases are often spread out widely
- Examples: heart disease, cancer, diabetes
Communicable diseases
These diseases can be passed from one person to another through various methods like direct contact, airborne droplets, or contaminated food and water.
Key features of communicable diseases:
- Number of cases can change rapidly
- Cases are often found in the same area
- Examples: colds, flu, measles, food poisoning
The rapid spread of communicable diseases is why public health measures like vaccination and quarantine are so important.
Factors affecting health
Diseases aren't the only things that affect your health. Many interconnected factors play a role in determining overall wellbeing. Other factors include:
- Diet
- Stress
- Life situations
Understanding how these factors interact is essential for maintaining good health.
Critical Concept: Disease Interactions
Different health problems can make each other worse. This creates a cycle where one condition can lead to multiple health issues:
- Immune system problems → more likely to get infectious diseases
- Allergic reactions → can cause skin rashes and asthma
- Serious physical illness → can lead to mental health problems like depression
- Viruses in cells → can trigger cancer
This is why treating health problems early and maintaining overall wellness is so important.
Real-life example: stomach ulcers
Worked Example: Understanding Disease Classification
H. pylori is a bacterium that lives in people's stomachs.
Key facts:
- Most people get infected as children from family members
- About 20% of UK people have this bacterium
- About 15% of those people develop stomach ulcers
- Taking too much aspirin can also cause stomach ulcers
Analysis: Is it communicable or non-communicable?
This case demonstrates the complexity of disease classification!
- H. pylori can spread between people (making it communicable)
- However, most infected people don't develop ulcers
- Whether you get ulcers depends on many factors including genetics, lifestyle, and other health conditions
- Therefore, stomach ulcers might be considered non-communicable even though they're caused by a communicable pathogen
Key Points to Remember:
- Health means physical, mental AND social wellbeing - all three matter
- Non-communicable diseases cannot spread between people (like cancer)
- Communicable diseases can spread between people (like colds)
- Different health problems can make each other worse
- Many factors affect health, not just diseases