How do infectious agents attack the human body? Explain by giving the known examples specifically their entry points and target organs? class 9 ch-science why do we fall ill? plz give the best answer I will make him brainiest
Answers
Answer:
Keynotes for Chapter - Why Do We Fall Ill, are:
Health
Health is a state of complete physical, mental and social wellbeing.
Disease
Any disturbance in the structure or function of any organ or part of body
It may be caused due to the attack of pathogens (virus, bacteria), lack of nutritious diet/balanced diet and lack of public health services.
CBSE Class 9 Science Syllabus 2020-2021
Types of Disease
Diseases are basically of two types. They are:
(i) Acute Disease
The disease which lasts for only a short period of time is called Acute Disease.
For example: Influenza (Flu), Common cold, etc.
(ii) Chronic Disease: The disease which lasts for a long period of time is called Chronic Disease
For example: TB, Cancer, etc.
Difference between Acute Disease & Chronic Disease
S. No.
Acute Disease
Chronic Disease
1.
They are short duration diseases.
They are long lasting diseases.
2.
Patient recovers completely after the cure.
Patient does not recover completely.
3.
There is no loss of weight or feeling of tiredness afterward.
There is often loss of weight of feeling of tiredness.
4.
There is short-duration loss of work and efficiency.
There is a prolonged loss of work and efficiency.
Causes of Diseases:
Causes of diseases are explained below:
Immediate and Contributory Cause
Immediate cause: The organisms that enter our body and cause the disease are termed as an immediate cause. For example, virus, bacteria, protozoa etc.
Contributory cause: The secondary factors which led these organisms enter our body are termed as a contributory cause. For example, dirty water, contaminated food, improper nourishment, poor standard of living, etc.
Infectious and Non-infectious Cause
Infectious causes:
They include the agents like microbes or micro-organisms as the immediate causes which spread the disease from an infected person to a healthy person.
Non-infectious causes:
The disease which does not spread by contact between infected and healthy person through air and water, is called non-infectious disease.
Infectious and Non-infectious Diseases
Infectious Diseases:
The diseases which spread due to infection by micro-organisms are called infectious diseases.
When a disease causing organism enters our body it causes infection, it multiplies and grows in the body called host and micro-organisms multiplies in the host body.
Answer:
Why do we Fall Ill. ... Common examples of diseases caused by viruses are the common cold, ... and signs of an infection will be if we know what the target tissue or organ is, and the ...