Class 9th, 14th chapter from NCERT

1. Why do we fall
ill ?

2. Grandmother Dress
well Reputation
Insanitation
Uncomfirtable
Grandmother
Dress well
Reputation
Insanitation
Polluted area
Uncomfortable

3. • ‘Health’ is therefore a state of being well
enough to function well physically,
mentally and socially.

4. • Disease – Any disturbance in the structure
and /or function of any organ or part of
body.

5. TYPES OF DISEASES
• Acute disease – Some diseases last for
only very short periods of time, and
these are called acute diseases.
E.g. common cold

6. • Other ailments can last for a long time,
even as much as a lifetime, and are
called chronic diseases.
E.g. elephantiasis, tuberculosis

7. Comparison of damages to health
by acute & chronic diseases
• Common cold
• Tuberculosis

8. Get better & become well within a
week or so
- short of breath
- lose weight
- feel tired all the time

9. • Prolonged general poor health if we have
a chronic disease

10. Types of diseases
• Infectious disease – Communicated
from diseased person to healthy person.
Caused by some biological agents /
pathogens like – Viruses, bacteria,
protozoan, nematodes, fungi
• Non-infectious disease – Restricted
only to those persons who are suffering.
Diseases that are not caused by
infectious agents.

11. INFECTIOUS DISEASES
• Infectious agents
• Means of spread
• Organ specific & tissue specific
manifestation
• Principles of prevention

12. Infectious agents - Organisms that
can cause disease are found in a
wide range of such categories of
classification.

13. Infectious agent Disease
Virus Common cold, influenza,
dengue fever, AIDS
Bacteria Typhoid fever, cholera,
tuberculosis, anthrax
Fungi Many common
infectious disease
Protozoan Malaria, kala azar
Worms worm infections,
elephantiasis

14. Why is it important
that we think of these
categories
of infectious agents?

15. As an example, let us take
antibiotics.
They commonly block biochemical
pathways important for bacteria. Many
bacteria, For example, make a cell-wall to
protect themselves. The antibiotic
penicillin blocks the bacterial processes
that build the cell wall. As a result, the
growing bacteria become unable to make
cell-walls, and die easily.

16. Means of spread of infectious
disease
1. Air born diseases Common cold,
pneumonia, tuberculosis
2. Water born
diseases
Cholera, amoeboisis
3. Sexually
transmitted
diseases
Syphilis, AIDS
4. Through vectors Anopheles mosquitoes –
vector of malaria

17. Organ specific & tissue specific
Manifestations
After entry of microbes in our body
where do they go?

18. Answer depends on Point of
entry :
• e.g. tuberculosis - caused by bacteria - entry
point through Nose to lungs

19. • e.g. jaundice – caused by viruses – through
mouth to liver

20. To reduce the effects of the disease :-
This can be done by taking medicines to bring down
the effects of the disease like fever, pain or loose
motions etc. and by taking bed rest to conserve our
energy.
To kill the microbes
This can be done by taking suitable antibiotics and
drugs which kills the microbes and the disease is
cured.
Principles of treatment

21. He who has health, has hope;
and he who has hope, has
everything.

22. Project By:
Anjali Ahuja