Basic concepts on health, disease, prevention and treatment for 14-year-old students

1. Health and Disease
Table of Contents:
1.Definitions.
2.Determining factors.
3.Types of disease.
4.Body’s defences against infection:
• External defences.
• Internal defences.
5.How to prevent diseases.
6.How to cure infectious diseases.

2. Definitions:
• HEALTH: Absence of physical or
mental disease.
• DISEASE: a condition that causes
problems in, or damage to, a specific
part of the body.
According to the W.H.O.:
HEALTH is the state of complete physical,
mental and social well-being.

3. Determining factors:
• A healthy environment. Free of air and water pollutants
Diet, exercise, sleeping
• Healthy habits and lifestyle. time…
Age, gender, genetic
• Personal characteristics. factors…
• Efficient and affordable health-care system.
Developed vs developing countries

4. Types of disease
• By origin:
Rabies, AIDS, cold, measles, chicken pox, flu, malaria,
– Infectious. pneumonia, tuberculosis…
– Non-infectious. Depression, goiter, obesity, cancer, diabetes…
• By appearance and duration:
– Acute. Flu
– Chronic. Arthritis, Alzheimer’s
• By incidence in the population:
– Sporadic - Endemic -Epidemic -Pandemic
Stroke Malaria Flu AIDS

5. Questions
• Types of pathogenic microorganisms?
Disease caused by each one?
BACTERIA: cholera, FUNGI: athlete’s foot,
tuberculosis, salmonellosis. mycosis, candidiasis.
PROTOZOA: malaria, VIRUSES: AIDS, flu, cold,
sleeping sickness. polio, chicken pox, rubella.
• How are infectious diseases transmitted?
Direct Contaminated
contact water, food or air Contact
Touchin with
g objects vectors

6. Body’s defences against infection
Do you catch an illness every time you
come across a pathogen? Why not?

7. External defences
They prevent pathogens from entering our
body.
1.EPITHELIA. Cover our external surface (skin) or
Main characteristics?
line our cavities.
2.FLUIDS like saliva, tearsDo your tears protect you?
and gastric juices.
3.OTHER MICROORGANISMS growing on our
skin or in the digestive and respiratorythis?
How is tracts.

8. Intruder Alert!
A: Everyone remain calm, the immune system
comes to the rescue!
B: Who?
A: a collection of white blood cells which give us
resistance and capacity to fight any pathogenic
agent.
B: Cool! What a
dialogue!

9. Internal defences
• NON-SPECIFIC: PHAGOCYTES.
They will ingest any type of microorganism or
foreign particle (innate immunity).
• SPECIFIC: LYMPHOCYTES.
They produce antibodies: proteins that are
specific to one antigen (any foreign molecule).
Specific antibodies bind to specific antigens
causing their destruction (acquired immunity).

10. How can we prevent diseases?
• Healthy habits. Hygiene, balance diet, get enough sleep,
exercise regularly, avoid drugs…
• Keep up to date on your vaccinations.
What is a vaccine? A preparation which contains
dead or attenuated pathogens, or just specific parts
of them.
What for? The immune system will produce specific
antibodies and will keep an immune memory.

11. How can we cure infectious diseases?
• Serum therapy.
A serum (fluid with antibodies) is administered to
a patient that urgently needs it.
How is it produced? How long will
this acquired immunity last?
• Drug therapy: medication.
Some chemicals can cure a disease or alleviate
its symptoms.

12. Food for thought
You have probably heard about some
bacteria becoming resistant to
antibiotics. How can this happen?