JKBOSE 9th Class Science Solutions Chapter 14 Why Do We Fall Ill

◆ According to WHO, health is a state of complete physical, mental and social wellbeing, and not merely an absence of disease or infirmity.

◆ Health is a state of being well enough to function well physically, mentally and socially.

◆ Health has three dimensions : Physical health, mental health and social health.

◆ Good health is characterised by-absence of disease, free from social and psychological tensions ; self-confidence and efficient working.

◆ Good health brings all round progress and is real wealth of an individual.

◆ Good health is adversely affected by over population, environmental pollution, poverty, ignorance, unhealthy sexual life, etc.

◆ Personal health includes four aspects: Personal cleanliness, exercise, rest and healthy habits.

◆ Basic conditions for maintaining good health are: Balanced diet; proper habits; exercise and relaxation habits, clean food, air and water; avoiding hazardous both substances; proper education, etc.

◆ Different organs of different systems show interactions and interdependence.

◆ Supply of food is must for proper functioning of organs to keep a person healthy.

◆ Food is that substance which provides energy, helps in repair of body tissues; provides materials for growth and provides resistance to diseases. Scientific study of food is called dietetics.

◆ Disease literally means being uncomfortable.

◆ Diseases are classified as acute or chronic, depending on their duration.

◆ Disease may be due to infectious or non-infectious causes.

◆ Infectious agents belong to different categories of organisms and may be unicellular and microscopic or multicellular.

◆  Health and disease are antagonistic to each other. Health is the state of body when all the organs and systems are functioning properly while disease is the condition which interferes normal functioning of the body and impairs the health.

◆ On the basis of period of occurrence, diseases are of two types : Congenital (inborn diseases e.g. Haemophilia, albinism) and acquired (during one’s own life span) diseases.

◆ Differences between infectious and non-infectious diseases

Characters	Infectious diseases	Non-infectious diseases
1. Transmission	Can be transmitted from infected person to a healthy person.	Cannot be transmitted from an infected person to a healthy person.
2. Causative agents	Micro-organisms called pathogens.	Deficiency of nutrient or hormone or degeneration of tissue; or hypersensitivity of body; or tumour formation.
3. Nature	They are brought about by extrinsic factor.	They are brought about by intrinsic factors.
4. Examples	Typhoid, Cholera, T.B., AIDS, Malaria etc.	Diabetes, Kwashiorkor, Marasmus, Goitre, Cancer, Allergy etc.

◆ The category to which a disease-causing organism belongs decides the type of organism belongs decides the type of for treatment.

◆ Infectious agents are spread through air, water, physical contact or vectors (mosquito bite),

◆ Prevention of disease is more desirable than its successful treatment.

◆ Infectious diseases can be prevented by public health hygiene measures that reduce exposure to infectious agents.

◆ Common communicable diseases. The following table shows some important diseases caused by bacteria, fungi and protozoa ;

Name of causative agent	Diseases
Bacteria	Pneumonia, Tetanus, Tuberculosis, Cholera, Food Poisoning, Sexually transmitted diseases.
Viruses	Chicken pox, poliomyelitis, influenza, AIDS.
Fungi	Skin diseases, Food poisoning.
Protozoans	Malaria, Kala-Azar, Amoebic dysentery, and African sleeping sickness.
Helminthes	Taeniasis, cysticercosis, Ascariasis, Elephantiasis.

◆ Principles of Prevention. Following three limitations are normally confronted while treating an infectious disease:

• If a person has a disease, his/her body functions are damaged and may never recover completely.

• Treatment will take time, which means that person suffering from a disease is likely to be bedridden for sometime even if given proper treatment.

• The person suffering from an infectious disease can serve as the source from where the infection may spread to other people. It is because of such reasons that prevention of diseases is better than their cure.

◆ Action of antibiotics. Antibiotics commonly block biochemical pathways important for bacteria. Many bacteria, for example, make a cell-wall to protect themselves. The best illustration is action of penicillin. It blocks 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 don’t 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 AVE FRAU strains ons srute antibiotics work against many species of bacteria making cell-walls. Similarly, many an rather than simply working against one.

◆ Pulse Polio is an immunization campaign established by Government of India in 1994 to eradicate poliomyelitis (polio) in India by vaccinating annually all children under age five against polio.

◆ These vaccines form the public health programme of childhood immunisation for preventing infectious diseases.

◆ Diseases can be treated either by symptom directed measures or by killing the microbes through the use of antibiotics.

◆ Infectious diseases can also be prevented by using immunisation,

◆ Effective prevention of infectious diseases in the community requires that everyone should have access to public hygiene and immunisation.

⇒ BCG. Bacillus Calmette Guerin) a vaccine to provide immunity against T.B. Deng fever is a viral disease whose vector is Aedes aegypti.

⇒ WHO. World Health Organisation.

⇒ Serum. It is pale yellow coloured liquid which is separated from blood clot after it has undergone coagulation.

⇒ Pathogen. Disease causing organism.

⇒ Paralysis. loss of power of voluntary movements.

⇒ Therapy. Treatment of diseases.

⇒ Vaccine. A preventive inoculation which prevents the occurrence of disease by stimulating the immune system.

⇒ Health. It is a state of physical, mental and social well-being.

⇒ Disease. Any condition which interferes with the normal functioning of body.

⇒ Symptom. The condition which a person feels, like, headache, watering of eye, loose motions, fever etc. are termed symptoms of a disease.

⇒ Acute disease. Diseases which occur very rapidly, but occur for short period.

⇒ Chronic diseases. Diseases which last for long period and cause prolonged poor health.

⇒ Community health. Sum total of activities which help in improvement of health of community.

⇒ Deficiency diseases. Diseases caused due to deficiency of a nutrient or a hormone.

⇒ Acquired diseases. Diseases developed during own life span.

⇒ Congenital diseases. Inborn diseases which occur from birth.

⇒ AIDS. Acquired Immuno-Deficiency Syndrome.

⇒ PEM. Protein-Energy Malnutrition : Deficiency of proteins and food calories.

⇒ Communicable diseases. These are transmitted from one man to another. These diseases are caused by Virus Bacteria, Protozoa, Fungi and Worms.

⇒ Infection. It is the interaction between the host and the parasite with a competition for superiority.

⇒ Incubation period. The period between the entry of the organism inside the body and appearance of symptoms of disease.

⇒ Contagious diseases. Diseases which can be spread from an infected person to healthy person by actual contact.

⇒ 24th March world T.B. Day.

⇒ 20th August is Malaria Day

Ans.— The conditions essential for good health are :

1. Proper nutrition or balanced diet and one should be disease free.

2. Social equality and harmony are necessary for individual good health.

Ans.— Disease means uncomfortable. The discomfort may be due to a particular cause. Disease is any condition which interferes with the normal functioning of body and impairs the health. The conditions essential for being free of disease are :

1. Proper diet.

2. Good habits such as avoiding habit forming substances and adopting clean and healthy sexual life.

Ans.— Different. It is possible to be in poor health without actually suffering from a particular disease. This is particularly true of social and mental health, where we can be in poor health without there being a cause in the form of an actual disease. This is the reason why, when we think about health, we think about societies and communities. On the other hand, when we think about disease, we think about individual sufferers. But otherwise, there is one similarity. If the conditions which are essential for good health are maintained then there are no chances of getting a disease.

Ans.— In case there is a disease, either the functioning or the appearance of one or more systems of body will change for worse. These changes give rise to symptoms or signs of disease.

1. Fever

2. Loss of appetite with feeling of nausea and vomiting.

3. Loose motions.

Doctors will look for signs of disease on the basis of symptoms. Sign will provide definite indication of the presence of a particular disease.

Ans.— (a) Jaundice is a chronic disease; it will have very drastic long term effect on people’s health as compared to getting affected by lice or appearance of acne. Jaundice may have fatal effect on body.

Ans.— 1. Nourishing food is good for health and simple food is easy to digest.

2. Such a diet contains adequate nutrients for speedy recovery.

Ans.— Communicable diseases are spread by microbial disease causing agents. The different agents are air, water, food droplets, sexual act, casual physical contacts or through vectors.

Ans.— A. General methods.

1. The general ways of preventing infections mostly relate to preventing ex everyone. exposures.

2. Availability of proper or sufficient food for everyone.

3. Drinking soft potable water.

Ans.— Immunisation. Process or procedure of making a person immune to a disease by artificial method.

Ans.— (a) The vaccines against tetanus, diphtheria, whooping cough, measles, polio are available at primary health centre. These form public health programme of childhood immunisation.

(b) Diphtheria and whooping cough are major health problems.

Ans.— (a) Change in habit. Twice-Influenza and diarrhoea.

(i) Avoid contact with infected person.

(ii) Drinking clean water.

(iii) Consume healthy nourishing food.

(b) Change in Surroundings. Cleanliness. Proper disposal of household wastes.

Ans.— To reduce incidence of infectious diseases following steps are taken.

1. Prevention of infection by avoiding exposure.

2. Immunisation.

3. Wear gloves and masks.

4. Take prophylactic medicines.

Ans.— The common diseases are :

1. Loose motions

2. Cough and cold

3. Malaria fever.

1. Reduce the effects of infectious disease.

2. Public cleanliness is important for individual health. Kill the cause of disease by using medicine that kill microbes.

3. Providing immunisation to all the people.

4. Use of clean drinking water.

1. Baby keeps crying.

2. Body of baby feels hot.

3. Eyes start watering.

4. Cough.

5. Loose motions.

6. Vomiting.

(b) Sickness. The manifestation of disease results in sickness. Doctor conducts some tests and from the symptoms he establishes the sickness.

Ans.— When a person is on four days fast after recovering from malaria and is taking care of someone suffering from chicken pox is likely to fall sick because of less of food. Organ systems such as liver have not recovered properly. A person will get infected with chicken pox as the defence system is also affected during malaria.

Ans.— A person is likely to fall sick when his friend is suffering from measles. It is an infectious and contagious disease. The infection is through droplet.

Ans.— Modes of transmission of disease.

Ans.—  Airborne diseases.

Ans.—1. Providing safe and clean drinking water.

2. Providing clean environment to prevent vector borne infections.

3. Adopting public hygienic measures.

4. Immunisation (vaccination).

5. Sterilisation of articles used by patients.

6. Isolation of patients from healthy person.

7. Health education.

Ans.—Organ-specific and tissue-specific manifestations depend on the target organ which the microbes target after their entry. They are as follows :

Target organ	Specific manifestation
1. Lungs	Cough, breathlessness, chest pain and may be bloody sputum as in TB and lung cancer.
2. Liver	Inflammation of liver cells leading to jaundice characterized by yellowness of skin and eyes as in Hepatitis.
3. Intestine	Inflammation of intestinal mucosa leading to acute diarrhoea and dehydration as in cholera.
4. Nasal chambers	Inflammation of nasal mucosa leading to sneezing, bronchitis, coughing, fever, etc. as in influenza.
5. Brain	Headaches, vomiting, fits or unconsciousness.

Ans.— AIDS (Acquired Immuno-Deficiency Syndrome)

(a) Cause. AIDS is caused by a retro-virus-HIV (Human immuno-deficiency virus). In India, it was first reported in the prostitutes of Chennai in 1986. It is a pandemic disease.

(b) Transmission. Human infection occurs through :

1. Unprotected sexual intercourse,

2. Use of contaminated syringes,

3. Blood transfusion,

4. Organ transplantation,

5. Common razor of the barbers, etc.

Effects. It causes damage, decrease in number of platelets, swollen lymph nodes, night sweats, loss of memory, etc. It is a 100% fatal disease.

Ans.—Incubation period of AIDS virus is of about 28 months.

Diagnosis by y ELISA test and Western Blot test.

Symptoms. HIV kills the Helper T-lymphocytes. It is characterized by following symptoms :

1. Prolonged fever.

2. Swollen lymph nodes.

3. Weight loss and loss of appetite.

4. Unexplained bleeding.

5. Loss of memory and mental ability.

6. Patient becomes susceptible to other infectious diseases.

7. Night sweats.

Ans.— Preventive measures. Involves educating the high risk groups; use of disposable syringes; screening tests of blood, organs, semen, etc; monogamous relationship; avoiding prostitution, polygamy and heterosexuality, using condoms, avoiding the use of common razor; etc.

Treatment. Drugs like AZT (Azidothymidine), TIAS injection and Protease inhibitors, etc. are known to suppress AIDS virus. Efforts are on for a vaccine against the virus. Ist December is World AIDS Day.

NACO – National Aids Control Organisation.

Ans.— Structure of HIV Virus.

Ans.— Disease. It is defined as a condition of the body or a part of it in which functions are disturbed. The word disease means lack of ease and comfort. Health. It is a state of complete physical, mental and social well-being. Health is also linked with social environment and cultural background.

Ans.— Refer to Basis and Basics.

Ans.— Refer to Basis and Basics.

Ans.— Differences between congenital and acquired diseases

Congenital Diseases	Acquired Diseases
1. They are present from birth.	1. They are acquired after birth and during the life span of an individual.
2. Inherited from parents to offsprings.	2. They are not passed onto the offsprings.
3. They are caused due to gene mutations or chromosomal mutations.	3. They are caused due to pathogens; or deficiency of hormone; or degeneration of tissues; or cancer growth.

Ans.— 1. By direct contact with an infected person e.g. Leprosy, chicken-pox etc.

2. By droplet infection e.g. Diphtheria, tuberculosis, etc.

3. By contact with soil e.g. bacterial cysts of tetanus.

4. By animal bite e.g. rabies viruses

5. Transplacental transmission e.g. viruses of German measles and AIDS.

Ans.— (i) Sources of diseases are those sites which are occupied by the pathogens before entering inside the human body. These are also called reservoirs of infection.

(a) Carriers or vectors e.g. Plasmodium (female Anopheles).

(b) Soil e.g. bacterial cysts of Clostridium tetani.

(c) Air e.g. bacterial cysts of TB.

(d) Food and water e.g. bacterial cysts of cholera.

Ans.— Organ specific and tissue specific manifestation. Human body has a number of organs, tissues and systems. Every pathogen has developed adaptation to infect a particular organ, tissue or system. In some cases the organ or tissue specificity depends upon the portal of entry while in others it is not so. A few examples are mentioned as follows :

1. If disease-causing microbes enter with air via the nose, they are likely to go to the lungs, e.g., bacteria which cause tuberculosis of lungs.

2. Virus that causes HIV infection, enters the body through sexual organs during sexual contact blood transfusion, sharing of needles and then tends to spread to lymph nodes throughout the body. J6t6q

3. If the pathogenic microorganisms enter via mouth, they are likely to stay in the lining of the gut (e.g. typhoid-causing bacteria) or these pathogens can also go to the liver the viruses that cause jaundice.

4. Malaria-causing microbes are transmitted through mosquito bite, and move to the liver and then to the red blood cells (R.B.Cs).

Ans.— Differences between symptoms and signs

Symptoms	Signs
1. They indicate presence of disease.	1. They provide information about the presence of particular diseases.
2. They are collective manifestation of a number of diseases of of particular parts organ.	2. They are distinct for different diseases.

Ans.— Health is at risk in case of cyclone because :

1. Social environment is disturbed as it is an important factor in case of individual health.

2. Garbage collected in places is source of multiplication of microbes and breeding place for various vectors.

3. Stagnant water will provide breeding surface for mosquitoes and other such disease spreading agents.

Ans.— Differences between acute diseases and chronic diseases

Acute diseases	Chronic diseases
1. They occur very rapidly but for only short period.	1. These diseases last for a long time and could be dangerous.
2. Do not cause major effects on general health.	2. They have prolonged and major effects on general health.
3. Examples: Common cold, Cough.	3. Examples: T.B., Cancer, Diabetes, Arthritis.

Ans.— Refer to Basis and Basics.

Ans.— Viruses do not have their own metabolic pathways at all, and that is the reason why antibiotics do not work against viral infections. In case of common cold, taking antibiotics does not reduce the severity or the duration of the disease.

Ans.— 1. Hydrophobia is another name of a viral disease called Rabies.

2. It is caused by a RNA-virus, Rabies virus, which is injected in the human being along with saliva of rabid animals like dogs, cats, monkeys etc.

3. Because the virus damages the motor neurons of brain and spinal cord, so causing paralysis and death.

Ans.— 1. AIDS is characterized by immuno deficiency and wasting of body parts.

2. It is caused by Human Immuno deficiency Virus (HIV).

3. HIV attacks helper T-lymphocytes, so causing cell-mediated immuno deficiency, so making the body more prone to various infections.

Ans.— (i) Epidemic jaundice is commonly called Hepatitis-A.

(ii) It is characterized by yellowing of skin, urine and stool due to damage to liver cells and overproduction of bilirubin.

(iii) It can be prevented by proper sanitation, use of boiled or ozonised intramuscular injection of human immunoglobulins.

Ans.—The body has two lines of defence against pathogens :

1. A non-specific defence mechanism comprising physical and chemical barriers and inflammatory reactions.

2. A specific defence mechanism, the immune system. These two mechanisms ward off constant attacks by pathogens from outside and assaults from within.

Ans.— Differences between active immunization and passive immunization

Active Immunization	Passive Immunization
1. Antigens are introduced from outside which trigger off the formation of antibodies in the body.	1. Ready – made antibodies are introduced into the body.
2. It does not provide immediate relief.	2. It provides immediate relief.
3. Immunity thus achieved is long lasting.	3. It is not long lasting.

Ans.— Vaccines are produced by deliberate infection of animals, recombinant DNA techniques coupled with hybridomas have opened up the way for custom-made monoclonal antibodies for preventive and therapeutic use. The vaccination prepares the body for to fight against the attack.

Ans.— Vector borne diseases e.g.

Vector	Disease
Tse Tse fly (Glossina)	African sleeping sickness
Sand fly (Phlebotomus)	Kala-azar and Oriental sore
Female mosquito (Anopheles)	Malaria
Rat flea (Xenopsilla)	Bubonic plague
Aedes mosquito	Yellow fever, Dengue.

Disease	Casual Organism
1. Malaria	Plasmodium vivax
2. Rabies	Rabies-virus
3. Influenza	Myxovirus influenzae
4. Tuberculosis	Mycobacterium tuberculosis
5. Typhoid	Salmonella typhosa.

Ans.— Structure of disease causing agents.  

Ans.—Proteins, Carbohydrates, Lipids, Nucleic acid, Water and mineral salts etc.

Ans.— Food is necessary for cell, tissue functions and maintenance.

Ans.— Health is a state of being well enough to function well physically, mentally and socially.

Ans.— Personal and community issues both matters for health.

Ans.— Good economic conditions of jobs are needed for individual health.

Ans.— Any condition which interferes with the normal functions of the body and impairs the health. It literally means being uncomfortable.

Ans.— Symptoms of disease are things we feel as being wrong, e.g. headache, cough, loose motions.

Ans.— Signs indicate a little more definite indications of presence of disease.

Ans.— (i) Acute diseases and (ii) Chronic diseases.

Ans.— The diseases which last only for short period of time.

Ans.— Diseases which last for long time, even life time are called chronic diseases. Example Elephantiasis.

Ans.— (1) Congenital diseases and (ii) Acquired diseases.

Ans.— Diseases present in the body from the birth. They are mostly hereditary disorders.

Ans.— (1) Gene mutations (ii) Chromosomal disorders (iii) Environmental factors.

Ans.— Lysozymes are the secretions present in tears and saliva which digest the bacterial cell wall and thus kill the bacteria.

Ans.— Helicobacter pylori.

Ans.— Robin Warren and Barry Marshall.

Ans.— Peptic ulcer.

Ans.— Viruses, Bacteria, Fungi and some Protozoans.

Ans.— Common cold, Influenza, Dengue fever and AIDS.

Ans.— Acquired immuno deficiency syndrome.

Ans.— Because the toxins of Rabies-virus damage the motor neurons of the brain.

Ans.— Human-immuno deficiency virus.

Ans.— Macculoch (1827).

Ans.— Penicillin blocks the pathway that build the cell wall as a result growing bacteria are unable to form a cell wall.

Ans.— Viruses do not have their own biochemical pathways, instead they utilize the machinery of cells they attack.

Ans.— 1. General way is a preventing exposure.

2. Immune system.

Ans.— Edward Jenner.

Ans.— Vectors. They are organisms which spread the disease agents from infected person to a healthy person.

Ans.— Whooping cough, Diphtheria, Measles, Polio and Tuberculosis.

(A) physically

(B) mentally

(C) socially

(D) All of above.

Ans.— (D) All of above.

(A) Air

(C) Food

(D)  All of above.

Ans.— (D)  All of above.

(A) T.B.

(B) Leprosy

(C) Food poisoning

(D) None of above.

Ans.— (A) T.B.

(A) Communicable diseases

(B) Degenerative diseases

(C) Deficiency diseases

(D) Allergies.

Ans.— (B) Degenerative diseases

(A) Jaundice

(B) Whooping cough

(C) Tuberculosis

(D) Malaria

Ans.— (A) Jaundice

(A) Leptospira

(B) Vibrio

(C) Pasteurella

(D) Traponema.

Ans.— (D) Traponema.

(A) malaria

(B) kala azar

(C) tetanus

(D) diptheria.

Ans.— (C) tetanus

(A) Yellow fever

(B) Typhus

(C) Plague

(D) Filariasis.

Ans.—(A) Yellow fever

(A) Mumps

(B) Rabies

(C) AIDS

(D) Tuberculosis.

Ans.— (D) Tuberculosis.

(A) Rickets

(B) Amoebiasis

(C) Diabetes

(D) Cancer.

Ans.— (B) Amoebiasis

(A) Louise Pasteur

(B) Edward Jenner

(C) Marshal and Warren

(D) Robert Koch.

Ans.— (C) Marshal and Warren

(A) SARS virus

(B) Staphyloccus bacteria.

(C) Helicobacter pylori

(D) Trypanosoma.

Ans.— (C) Helicobacter pylori

(A) All lymphocytes

(B) activated B cells

(C) cytotoxic T cells

(D) T₄ lymphocytes.

Ans.— (D) T₄ lymphocytes.

(A) Primary host

(B) Secondary host

(C) Intermediate host

(D) None of above.

Ans.— (B) Secondary host

(A) is formed by WBC

(B) help in production of WBC

(C) induce the formation of antigen

(D) None of above.