Quick Summary
Health is more than absence of disease. This chapter covers disease types, pathogens, immunity, vaccination, prevention, and healthy habits.
Key Definitions
- Health: Complete physical, mental, and social well-being.
- Disease: Disturbance in normal body function.
- Pathogen: Disease-causing organism.
- Communicable disease: Disease that spreads from one person to another.
- Non-communicable disease: Disease that does not spread by infection.
- Immunity: Ability of the body to resist disease.
- Vaccination: Administration of vaccine to develop immunity.
Types of Diseases
| Type | Meaning | Example idea |
|---|---|---|
| Communicable | Spreads through pathogens | Flu, malaria |
| Non-communicable | Does not spread by infection | Diabetes, hypertension |
| Deficiency disease | Caused by lack of nutrients | Anaemia, rickets |
| Genetic disease | Caused by inherited factors | Inherited disorders |
Pathogens and Spread
Pathogens include bacteria, viruses, fungi, protozoa, and worms. They may spread through air, water, food, vectors, direct contact, or contaminated objects.
Common Pathogens and the Diseases They Cause
Immunity and Vaccination
The immune system protects the body. Vaccination prepares the immune system to fight specific diseases by producing memory against pathogens.
Types of Immunity
- Innate (natural) immunity: present from birth — skin, mucus, stomach acid, WBCs.
- Acquired immunity: developed after exposure.
- Active: body makes its own antibodies (after infection or a vaccine) — long lasting.
- Passive: ready-made antibodies received (mother's milk, antiserum) — short lived.
How a Vaccine Works
This is the basis of programmes like polio and tetanus vaccination.
Prevention
- Maintain personal hygiene.
- Drink safe water.
- Eat balanced food.
- Control disease vectors.
- Follow vaccination schedules.
- Exercise regularly and sleep well.
Textbook Solution Strategy
1. Classify the disease first. 2. Mention cause, mode of spread, symptoms, and prevention. 3. For immunity questions, explain body defence and vaccination. 4. Use examples for each disease type. 5. Avoid vague answers like "be clean" without specific practices.
Important Questions
One Mark
- Define health.
- What is a pathogen?
- What is vaccination?
Two Marks
- Differentiate between communicable and non-communicable diseases.
- Write two methods of disease prevention.
- What is immunity?
Five Marks
- Explain types of diseases with examples.
- Describe immunity and vaccination.
- Explain causes and prevention of communicable diseases.
Common Mistakes
- Defining health only as absence of disease.
- Mixing communicable and non-communicable diseases.
- Forgetting vectors in disease spread.
- Writing symptoms without prevention.
Revision Checklist
- Health definition memorised
- Disease types compared
- Pathogen examples revised
- Immunity and vaccination understood
- Prevention points practised