why do we fall ill class 9 notes

1. БHealthБ
is a state of being well enough to function well physically, mentally, and socially. 2. БDiseaseБ ( disturbed ease) means being uncomfortable. One or more systems of the body will change, give rise to БSymptomsБ ( Cough, loose motions, pus formation, headache, fever, breathlessness, vomiting, fits, unconsciousness, inflammation, swelling and general effects - a Doctor look for the basis of symptoms).


Diseases are basically two types- Acute Disease & Chronic Disease 3. Acute Disease: The disease which lasts for only a short period of time is called Acute Disease Ex.


Common Cold. 4. Chronic Disease: The disease which lasts for long period of time is called Chronic Disease Ex. Tuberculosis. 5. Causes of Diseases : Most of the diseases have many causes, rather than one single cause, like unclean water, nourishment, genetic differences, genetic abnormalities e. g.


Based on the causes diseases are of two types: Non-Infectious Diseases and Infectious Diseases. 6. Non-Infectious Diseases: Not caused by infectious agents, mostly internal and non- infectious cause. Ex. Cancer 7. Infectious Diseases: Caused by infectious agents. (Please refer Fig. 13. 1 (a-e), NCERT Text Book Page- 181). a)The infectious diseases spread by agents are called as Communicable Diseases.


The antibiotic penicillin block the bacterial processes that build the cell -wall. As a result, the growing bacteria become unable to make cell walls, and die easily.


Human cells dont make a cell wall anyway, so penicillin cannot have such an effect on us. Penicillin will have this effect on any bacteria that use such processes for making cell walls. Similarly, many antibiotics work against many species of bacteria rather than simply working against one.