why do we fall ill class 9 biology , 14th chapter
DESCRIPTION
NCERT BOOK CHAPTER 14 OF SCIENCE CLASS 9THTRANSCRIPT
![Page 1: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/1.jpg)
WHY DO WE FALL ILL?
![Page 2: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/2.jpg)
What is health ?Health is the level of functional or metabolic effi ciency of a living organism. In humans, it is the general condition of a person's mind and body, usually meaning to be free from illness, injury or pain]] (as in "good health" or "healthy").
![Page 3: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/3.jpg)
Health is a state of physical, mental and social well being.
The conditions necessary for good health are :- i) Good physical and social environment. ii) Good economic conditions.iii) Social equality and harmony. Good physical and social environment includes clean
surroundings, good sanitation, proper garbage disposal and clean drinking water .
Good economic conditions includes job opportunities for all for earning to have nutritious food and to lead a healthy life.
Social equality and harmony are necessary for a healthy and peaceful life.
![Page 4: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/4.jpg)
Healthy Disease free
1. It is a state of physical, mental and social well being.
It is a state of absence from diseases.
2. It refers to the individual, physical and social environment.
It refers only to the individual.
3. The individual has good health. The individual may have good health or poor health.
2) Differences between Healthy and Disease free :-
![Page 5: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/5.jpg)
When a person is affected by a disease either the normal functioning or the appearance of one or more systems of the body changes for the worse.
These changes give rise to signs of the disease called symptoms.
On the basis of the symptoms the physicians look for the signs of a particular disease and conduct tests to confirm the disease.
![Page 6: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/6.jpg)
Maintaining healthAchieving and maintaining health is an ingoing process, shaped by both the evolution of health care knowledge and practices as well as personal strategies and organized interventions for staying healthy known as Lifestyle Management.
![Page 7: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/7.jpg)
The science builds on many sub-fields, including biology, biochemistry, physics, epidemiology, pharmacology, medical sociology. Applied health sciences endeavour to better understand and improve human health through applications in areas such as health education, biomedical engineering, biotechnology and public health.
![Page 8: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/8.jpg)
Role of science in healthHealth science is the branch of science focused on health. There are two main approaches to health science: the study and research of the body and health-related issues to understand how humans (and animals) function, and the application of that knowledge to improve health and to prevent and cure diseases and other physical and mental impairments.
![Page 9: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/9.jpg)
TYPES OF DISEASES.
Acute diseases:Diseases that last for
only very short period of time are called acute
diseases. Acute means brief and severe.
![Page 10: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/10.jpg)
CO
MM
ON
CO
LD
.
![Page 11: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/11.jpg)
Other diseases are more long –term, with the symptoms lasting for months or years. Such diseases are called chronic
diseases.
CHRONIC DISEASES:
![Page 12: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/12.jpg)
Tuberculosis [ T.B ]
It is an infectious disease.it includes swelling and tenderness of lymph gland often in the legs which may discharge secretion through skin.
Examples of chronic diseases
![Page 13: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/13.jpg)
![Page 14: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/14.jpg)
Ele
phanti
asi
s .
![Page 15: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/15.jpg)
A lower leg and a scrotum showing
the effect of elephantiasis.
![Page 16: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/16.jpg)
Diseases are of different types. They are :-
are
diseases which last only for a short period of time and does not have
long term effect on health. Eg:- cold, cough, typhoid, cholera etc.
are diseases which lasts for a long time and has long term drastic
effect on health. Eg :- diabetes, tuberculosis,
elephantiasis, arthritis, cancer etc.
Acute diseas
es Chronic disease
![Page 17: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/17.jpg)
Acute diseases will not have time to cause major effects on general health , but a chronic disease will effect drastically.
![Page 18: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/18.jpg)
Principles
of prevention
of diseases.
![Page 19: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/19.jpg)
1) For air borne microbes , we can prevent exposure by providing living conditions that are not over crowded .
1.General ways of prevention of
infectious diseases.
![Page 20: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/20.jpg)
we can prevent exposure by providing safe drinking water.
1)For water borne microbes
![Page 21: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/21.jpg)
, , we can provide clean environments . Such a clean environment, for example , would not allow mosquito breeding.
) For vector borne infections
![Page 22: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/22.jpg)
A vaccine is a biological preparation used as a preventive inoculation to confer immunity against a
disease. The preparation usually employs an innocuous form of the disease-causing agent, which
is in the form of killed or weakened bacteria or viruses. A vaccine may also be composed of the
toxins or surface proteins of the infecting organism.
Another way of prevention is through
VACCINATION.
![Page 23: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/23.jpg)
Examples of vaccines
BCG Vaccine used against
tuberculosis .Sabin vaccine used
against poliomyelitis.
![Page 24: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/24.jpg)
1)Congenital diseases
These diseases are those which are present since birth. They are caused due to genetic abnormality or due to metabolic disorders.
Types of diseases..
![Page 25: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/25.jpg)
2)Acquired diseases
These diseases are those which are developed after birth. They are classified
into two types.
1} Infectious diseases.2} Non-infectious diseases.
![Page 26: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/26.jpg)
Prevention methods of
some common diseases.
![Page 27: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/27.jpg)
TYPHOID.
Proper sanitation and
disposal of faecal matter
prevents infection .
TAB vaccination
provides immunity for
3 years .
Typhoral oral vaccine also
prevents typhoid.
![Page 28: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/28.jpg)
DIARRHOEA
Eatables should be covered to
prevent contamination .
Stale food should not be
consumed.
Proper personal hygiene is also very important
Community hygiene is also
important.
![Page 29: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/29.jpg)
Tuberculosis
Isolation and proper rehabilitation of the patient .
Avoidance of over crowding
Provision of good ventilation and better help to reduce the
incidence of the disease.
![Page 30: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/30.jpg)
It is caused by microbes or micro –organisms .These diseases can spread in the community .
Infectious diseases are caused by bacteria, viruses , fungi, and unicellular organisms like protozoans.Some multicellular organisms like worms also cause infectious diseases.
Infectious diseases caused by viruses are such as common cold ,influenza , dengue fever, AIDS etc.
Bacterial diseases of bacteria are typhoid fever , cholera, tuberculosis ,anthrax etc.
Common infectious skin diseases are caused by fungi
Protozoan cause diseases such as malaria ,kala-azar .Worms cause intestinal diseases as well as elephantiasis .
TYPES OF DISEASESINFECTIOUS DISEASES
![Page 31: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/31.jpg)
–These are not spread to other persons. These are of following types:-
i. Deficiency- caused deficiency of nutrients and hormones. E.g. diabetes , scurvy.
ii. Allergic – when body is hypersensitive to foreign elements. E.g. asthma
iii. Cancer- uncontrolled growth of certain tissues.iv. Mental disorder- depression ,anxiety etc.v. Addiction :- alcohol, drugs.vi. Degenerative- malfunctioning of important
organs .E.g. heart diseases.
NON- INFECTIOUS DISEASES
![Page 32: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/32.jpg)
Viral :- influenza , chickenpox , small pox ,common cold, dengue fever and AIDS
INFECTIOUS AGENTS
VIRUS
![Page 33: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/33.jpg)
Fungal :- ringworm etc.
![Page 34: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/34.jpg)
Bacterial :- cholera ,typhoid , tuberculosis and anthrax .
Bacteria
![Page 35: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/35.jpg)
Protozoan
Protozoan :- malaria , kala-azar
![Page 36: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/36.jpg)
Common cold (viral) cause – Rhino virus symptoms – sore throat , cough , headache.
Chicken pox (viral) symptoms – rashes, fever, aches , uneasiness.
Measles (viral) symptoms –red and watery eye, pink rashes, itching or
burning or rashes.
IMPORTANT DISEASES IN HUMAN
![Page 37: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/37.jpg)
Typhoid (bacteria)Cause- salmonella typhi. Symptoms- fever ,headache ,loss of appetite, skin rash
,either constipation or diarrhea.Tuberculosis-(BCG vaccine)
Cause – Mycobacterium tuberculosis. Symptoms – night sweats, fatigue, weight loss.
Malaria(protozoa)Cause –female anopheles mosquitoSymptoms –fever at interal,weakness .
Cancer Cause- abnormal and uncontrolled growth of cellsRisk factors – tobacco, alcohol, high fat diet , smoking.
HypertensionCause- blood pressure levels, stress, tension , salt
intake ,fat intake(large)
![Page 38: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/38.jpg)
Picture of Leishmania ,the protozoan organism that causes kala –azar .The Organisms are oval shaped ,and each has one long whip like structure . One organism(arrow )is dividing ,while a cell of the immune system (lower right ) has gripped on the two whips of the dividing organism and is sending cell processes up to eat up the organism . The immune cell is about ten micrometers in diameter.
![Page 39: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/39.jpg)
Picture of staphylococci ,the bacteria which can cause acne .
![Page 40: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/40.jpg)
Picture of an adult roundworm (Ascaris lumbricoides is the technical name )From the small intestine .The ruler next to it shows
![Page 41: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/41.jpg)
These categories of infectious agents are important factors in deciding what kind of treatment to use .Members of each one of these groups- viruses, bacteria , and so on –have many biological characteristics in common. All viruses , for example ,live inside host cells ,whereas bacteria very rarely do.
An antibiotic is a selective poison. It has been chosen so that it will kill the desired bacteria, but not the cells in our body. Each different type of antibiotic affects different bacteria in different ways. For example, an antibiotic might inhibit a bacterium's ability to turn glucose into energy, or its ability to construct its cell wall. When this happens, the bacterium dies instead of reproducing. At the same time, the antibiotic acts only on the bacterium's cell-wall-building mechanism, not on a normal cell's. Antibiotics commonly block biochemical pathways important for bacteria .These inhabit the growth of bacteria or kill them.Antibiotics do not work on viruses because viruses are not alive and viruses do not use biochemical pathways such as bacteria . A bacterium is a living, reproducing life form. A virus is just a piece of DNA (or RNA). A virus injects its DNA into a living cell and has that cell reproduce more of the viral DNA. With a virus there is nothing to "kill," so antibiotics don't work on it.
![Page 42: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/42.jpg)
Means of spread
of Diseases
![Page 43: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/43.jpg)
THREE COMMON
WAYS ,GERMS ARE SPREAD
![Page 44: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/44.jpg)
Germs can spread to the hands by sneezing, coughing, or rubbing the eyes and then can be transferred to other family members or friends. Simply washing your hands can help prevent such illnesses as the common cold or eye infections.
Nose, mouth, or eyes to hands to others:
![Page 45: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/45.jpg)
Hands to food:
Usually germs are transmitted from unclean hands to food by an infected food preparer who didn’t wash his or her hands after using the toilet. The germs are then passed to those who eat the food. Germs are also transmitted from raw foods, such as chicken, to hands while preparing a meal.
![Page 46: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/46.jpg)
Animals to people:
Wash your hands after petting animals or touching any surfaces they come into contact with.
![Page 47: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/47.jpg)
Direct transmission
refers to the transfer of an infectious agent from an infected host to a new host, without the need for intermediates such as air, food, water or other animals. Direct modes of transmission can occur in many ways:
Touching
Sexual intercourse
Biting
Direct projection of droplets
Across the placenta
![Page 48: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/48.jpg)
Indirect modes of transmission
Indirect transmission is when infectious agents are transmitted to new hosts through intermediates such as air, food, water, objects or substances in the environment, or other animals. Indirect transmission has three subtypes:
![Page 49: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/49.jpg)
Airborne transmission:
The infectious agent may be transmitted in dried secretions from the respiratory tract, which can remain suspended in the air for some time. For example, the infectious agent causing tuberculosis can enter a new host through airborne transmission.
![Page 50: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/50.jpg)
Vehicle-borne transmission: A vehicle is any non-living substance or
object that can be contaminated by an infectious agent, which then transmits it to a new host. Contamination refers to the presence of an infectious agent in or on the vehicle.
![Page 51: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/51.jpg)
Vector-borne transmission:
A vector is an organism, usually an arthropod, which transmits an infectious agent to a new host. Arthropods which act as vectors include houseflies, mosquitoes, lice and ticks.
![Page 52: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/52.jpg)
Organ-specific and tissue-specific
manifestations
![Page 53: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/53.jpg)
Microbes which enter our body are Likely to go to different Sites in our body such as :-
![Page 54: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/54.jpg)
I) MICROBES WHICH ENTERS THROUGH THE NOSE ARE LIKELY TO GO TO THE LUNGS. FOR EXAMPLE -BACTERIA WHICH CAUSE TUBERCULOSIS OF LUNGS.
![Page 55: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/55.jpg)
II) MICROBES WHICH ENTER THROUGH THE MOUTH ARE LIKELY TO STAY IN THE GUT SUCH AS BACTERIA WHICH CAUSES TYPHOID OR LIVER SUCH AS BACTERIA WHICH CAUSES JAUNDICE.
TYPHOID BACTERIA
![Page 56: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/56.jpg)
III) VIRUS WHICH CAUSES AIDS ENTER THE BODY THROUGH SEXUAL ORGANS DURING SEXUAL CONTACT AND SPREADS THROUGH THE LYMPH TO ALL PARTS OF THE BODY AND DAMAGES THE IMMUNE SYSTEM.
![Page 57: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/57.jpg)
IV) VIRUS WHICH CAUSES JAPANESE ENCEPHALITIS (BRAIN FEVER) ENTERS THE BODY THROUGH MOSQUITO BITE AND GOES AND INFECTS THE BRAIN.
![Page 58: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/58.jpg)
Principles ofTreatments
There two ways to treat an infectious disease. One would be
to reduce the effects of the disease and the other to kill the
cause of disease. For the first, we can provide treatments that will
reduce the symptoms .
![Page 59: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/59.jpg)
The symptoms are usually because of inflammation .for example we can take medicines that bring down fever, reduce pain or loose motions .
\
Treatment refers to the process of curing a disease or infection to bring back the organism to his normal health . Basic five principles for treating a disease are: 1) To reduce the symptoms of the disease. This is done by medicine, surgery, injection etc. to relieve the patient from pain and suffering.
![Page 60: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/60.jpg)
2) To remove the cause of disease. Removing the cause will result in avoiding the infection to spread further in the body of the patient. 3) To prevent the spread of the disease from infected individual to the healthy one. 4) To make the patient healthy again by helping him to overcome the effects of the disease like weakness etc. 5) To prevent the reappearance of the disease by vaccinating the person for that disease.
![Page 61: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/61.jpg)
One way is to use medicines that Microbes. The microbes can be Classified into different :-1. viruses2. bacteria3.Fungi4.Protozoa each of these groups of organisms will have some essential biochemical life
![Page 62: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/62.jpg)
Process which is peculiar to that group and not shared with the
other groups. These process may be pathways for the synthesis of new substances or respiration .
![Page 63: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/63.jpg)
These pathways will not be used by us either. For examples ,our cells may make new substances by a mechanism different from that used by bacteria .we have to find the drug that blocks the bacterial synthesis pathway without affecting our own .
![Page 64: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/64.jpg)
This is what is achieved by the antibiotics that we are all familiar with . Similarly, there are drugs that we are drugs that kill protozoa such as the MALERIA PARASITE . There are now effectively anti-viral drugs, for example, the drugs that keep HIV infection under control.
![Page 65: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/65.jpg)
Personal health depends partially on the active, passive, and assisted cues people observe and adopt about their own health. These include personal actions for preventing or minimizing the effects of a disease, usually a chronic condition, through integrative care. They also include personal hygiene practices to prevent
Self- care strategies
![Page 66: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/66.jpg)
The information gleaned from personal observations of daily living – such as about sleep patterns, exercise behaviour, nutritional intake, and environmental features – may be used to inform personal decisions and actions.
infection and illness, such as bathing and washing hands with soap; brushing and flossing teeth;, storing preparing and handling food safely; and many others.
![Page 67: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/67.jpg)
Q1: Which one of the following is an infectious disease?
(a) diphtheria(b) diabetes(c) hypertension(d) cancer
Q2: Elephantiasis disease can have
(a) short-term affect on our health(b) no effect on our health(c) long term affect on our health(d) sometimes bad effect on our health
MCQs
(
1: (a) diphtheria2: (c) long term affect on our health
![Page 68: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/68.jpg)
Q3: Ascaris worm lives in which part of human body?
(a) kidneys(b) liver(c) small intestine(d) large intestine
Q4: Microbes which enter the body through nose most likely affect
(a) liver(b) heart(c) brain(d) lungs
Q5: Which of the following is a viral infection?
(a) Diphtheria(b) Influenza(c) Cholera
(d) Typhoid
3: (c) small intestine4: (d) lungs5: (b) Influenza
![Page 69: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/69.jpg)
Q6: HIV virus when active in body mainly attacks on
(a) lungs(b) liver(c) immunity(d) nerves
Q7: An Organism which carries pathogens is termed as
(a) host(b) vector(c) parasite(d) predator
Q8: Diseases which are always present in certain location are called?
(a) epidemic diseases(b) endemic diseases(c) acute diseases(d) chronic diseases 6: (c) immunity
7: (b) vector8: (a) epidemic diseases
![Page 70: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/70.jpg)
Q9: DPT vaccines are administered to develop immunity against
(a) Tetanus(b) Diphtheria(c) Pertusiss(d) All of these
Q10: Anti-viral drugs are difficult to make because, viruses
(a) live outside the host cells(b) live inside the host cells(c) live in consumed food particles(d) live in blood stream
Q11: BCG vaccine is used to develop immunity against
(a) jaundice(b) polio(c) influenza(d) tuberculosis
9: (d) All of these10: (a) live outside the host cells11: (d) tuberculosis
![Page 71: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/71.jpg)
Q12: Which of the following is a communicable disease?(a) Rickets(b) Scurvy(c) Marasmus(d) Cholera
Q13: The causative organism for malaria is a:(a) bacteria(b) protozoa(c) virus(d) fungi
Q14: Vaccination helps in controlling diseases because (a) it develops resistance against the pathogen attack(b) it kills the pathogens causing disease(c) it blocks the food supplied to pathogens(d) it does not allow pathogens to multiply in hosts
12: (d) Cholera13: (b) protozoa14: (a) it develops resistance against the pathogen attack
![Page 72: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/72.jpg)
Q15: ORS is given in
(a) diarrhea(b) measles(c) typhoid(d) tetanus
Q16: Which of the following is an example of nutritional deficiency disease?
(a) Hypertension(b) Rickets(c) Diabetes(d) Gastroenteritis
15: (a) diarrhea16: (b) Rickets
![Page 73: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/73.jpg)
ANSWER SHORTLY
2-Marks Questions
![Page 74: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/74.jpg)
1.Define antibiotic?Ans: Antibiotic are the chemical substances produced by living organisms such as
bacteria, fungi,etc which can kill or stop the growth
of some pathogenic microorganism such as
fungi , bacteria
![Page 75: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/75.jpg)
2.What are vaccines?Ans: A vaccine is an antigen
that is injected. It causes the development of active immunity in the patient. It stimulates the production of antibodies . There are vaccines against tetanus,
polio, diphtheria etc.
![Page 76: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/76.jpg)
3. What is dehydration?Ans: Dehydration is the loss of water from body tissues which makes the patient dangerously ill in a short time. In case of dehydration the patient
becomes irritable, sudden weight loss, fever
, or fits.
![Page 77: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/77.jpg)
4.How food poisoning is caused?
Ans: Food poisoning by bacteria salmonella is
called salmonellosis. The infection of bacteria is contracted from sick farm animals through their milk , meat or
eggs.
![Page 78: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/78.jpg)
6.List some basic principle of prevention of infectious diseases?Ans: 1) Availability of proper and sufficient
food.2) Have regular check
up’s .3)Try to be in clean
environment.
![Page 79: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/79.jpg)
7. What do you mean by immunity?
Ans: The ability of an organism to resist a
particular infection is called immunity.
![Page 80: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/80.jpg)
8.Give a classification of diseases caused by
protozoa, viruses & bacteria.Ans: Diseases caused by
protozoa- Malaria.Diseases caused by viruses-
Influenza,jaundice,Rabies,Polio
Diseases caused by bacteria -T.B, Cholera, typhoid ,
diarhoea..
![Page 81: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/81.jpg)
9.D
raw
a labelled
dia
gra
m o
f st
ruct
ure
of
AID
S V
irus.
![Page 82: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/82.jpg)
a) Define disease? b)What are the two major categories of human diseases.
Give two examples of each ?Ans a)-Any functional or physical change from the natural state
that cause discomfort or disability is called a disease.Ans b) The major categories of human diseases are :
Communicable (infectious) diseases e.g.- Malaria ,jaundice. Non –communicable (non-infectious)diseases. e.g.– Cancer, diabetes.
What are the causes of non-infectious diseases?Ans- These are not spread to other persons and are not caused by
any infection are called non –infectious. Causes are-i. Genetic abnormabilities: Haemophilia, some type of
cancers .etc.ii. Internal causes : Such as high blood pressure can be caused
by excessive weight and lack of exercise.
QUESTIONS AND ANSWERS(3MARKS)
![Page 83: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/83.jpg)
What is infectious disease and their causes?Ans-These are spread to other person and are caused by microbes are called infectious disease. They are caused by – i) bacteria ii) viruses iii)Fungi iv)protozoan
List the causes of diseases .i. Infection ii. Poor health iii. Lack of proper and sufficient food iv. Lack of public services v. Genetic differences .
List four diseases caused by viruses?Ans- diseases caused by viruses are –• Common cold • Influenza • Dengue fever • AIDS
![Page 84: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/84.jpg)
What are the difference between communicable and non- communicable diseases?
COMMUNICABLE(INFECTIOUS ) DISEASES
NON-COMMUNICABLE (NON-INFECTIOUS )DISEASES
They are infectious diseases .They are transferred from a patient to the healthy person .
They are not infectious diseases and cannot be transferred from a patient to a healthy person.
They are caused by a pathogen (disease causing bacteria).
They are not caused by pathogen.
They are spread through some agency such as air , food , contact ,insects, etc.
They do not spread through any agency.
These are not caused by nutritional deficiency. These are due to infection.
They are caused by nutritional deficiency degeneration of organs or malfunctioning of a vital organ, not caused by infection.
![Page 85: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/85.jpg)
Explain why antibiotics are more effective in curing bacterial diseases than viral diseases.
Ans-Antibiotics are effective in curing bacterial and fungal infections (e.g.-tuberculosis)but they are ineffective in viral diseases (e.g.-common cold ).Antibiotics affect on life process of bacteria and inhibit their growth .On the other hand virus is just apiece of DNA (RNA ),not well defined life form .Viruses can reproduce inside host cells .They do not use biochemical pathways as used by other microbes (bacteria ,fungi , parasites).That's why antibiotic are ineffective in viral infections.
Define antibiotic? Explain how it is able to control bacterial infections but not viral infections?
Ans-Antibiotics (anti means against , biotic –living) are types of medications that destroy or slow the growth of bacteria. They are often termed as antibacterial .They work against the life processes of bacteria .Many bacteria ,for example ,make a cell-wall to protect themselves .The antibiotic penicillin blocks the bacterial processes that build the cell wall. Thus bacteria fail to build their cell –wall, stop multiplying and die out .Human cells don’t make a cell-wall anyway, so penicillin cannot have such effect on us.
![Page 86: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/86.jpg)
Give causes and remedy of i) Hepatitis ii)AIDS iii)MalariaAns - Causes Remedy i) Hepatitis is caused by virus - Hepatitis A and B vaccination (preventive measure) - Avoid eating stale food .
ii) AIDS is caused by HIV. - Avoid any type of infection - Now anti – viral drugs that keep HIV infection under control are available .
iii) Malaria is caused by -Avoid breeding of mosquito in stagnant
Plasmodium(Protozoan microbe) water ditches ,ponds,etc. Spread by bite of female - Consult doctor for treatment .Anopheles mosquito. -Use mosquito repellents.
![Page 87: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/87.jpg)
What Is Cancer? What Causes Cancer?ANS-Cancer is a class of diseases characterized by out-of-control cell growth. There are over 100 different types of cancer, and each is classified by the type of cell that is initially affected.Cancer harms the body when damaged cells divide uncontrollably to form lumps or masses of tissue called tumors (except in the case of leukemia where cancer prohibits normal blood function by abnormal cell division in the blood stream). Tumors can grow and interfere with the digestive, nervous, and circulatory systems, and they can release hormones that alter body function. Tumors that stay in one spot and demonstrate limited growth are generally considered to be benign. More dangerous, or malignant, tumors form when two things occur:1.a cancerous cell manages to move throughout the body using the blood or lymph systems, destroying healthy tissue in a process called invasion 2.that cell manages to divide and grow, making new blood vessels to feed itself in a process called angiogenesis. When a tumor successfully spreads to other parts of the body and grows, invading and destroying other healthy tissues, it is said to have metastasized. This process itself is called metastasis, and the result is a serious condition that is very difficult to treat.
![Page 88: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/88.jpg)
Long type questionQ -1 What is AIDS to be a ‘Syndrome’ and not a disease ?Ans-AIDS causing virus (HIV)enters the body of a person generally blood transfusion and spreads to lymph nodes . It damages our immune system and, thus, body no longer is able to fight off many minor infections. Instead, even a small cold infection can become pneumonia or minor gut infection may lead to severe diarrhoea with blood loss.
![Page 89: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/89.jpg)
The effect of minor diseases become to severe that they kill
the patients suffering from AIDS . In other words, there are no
specific disease symptoms for AIDS and the patients develops
complex diseases and symptoms. Therefore, AIDS is termed as
‘syndrome’ and not a disease.
![Page 90: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/90.jpg)
Q-2 what precautions will you take to justify “prevention is better than cure”Ans- the precautions are :-• Sanitation• Sterilization• Eradication of vectors• Proper and suffi cient food • Education• Isolation• Immunization against diseases
![Page 91: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/91.jpg)
Q-3 write the about infectious disease?Ans-INFECTIOUS DISEASES1.These occur due to external ( extrinsic) factors .2. These are caused by the attack of pathogens (viruses, bacteria, fungi, protozoans, worms)3. These can spread from infected person to healthy person (s).4.Infection is transmitted through direct contact or through medium (air, water ,food , insects ,etc. )
![Page 92: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/92.jpg)
Q-4 What do you mean by vaccination? Who first conceived the idea of vaccination?Ans- vaccination is a technique in which a preparation of antigenic protein of pathogen or weakened or dead pathogens are injected into a person to develop immunity in him with infection.Edward Jenner first conceived the idea of vaccination.
![Page 93: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/93.jpg)
Q-5 What do you mean by disease symptoms ? Explain giving two examples?Ans- symptoms of the disease are the manifestation or evidences of the presence of disease (s). These indicate that there is some abnormality in the body.EXAMPLES :- (i) Cough and breathlessness are symptoms of lung infection .(ii) Yellowness of sclera (white portion ) of eye and skin are symptoms of jaundice.
![Page 94: WHY DO WE FALL ILL class 9 biology , 14th chapter](https://reader033.vdocuments.us/reader033/viewer/2022061515/554b0826b4c905fa6d8b48d5/html5/thumbnails/94.jpg)
Thank you for
watching