MP Board Class 12th Biology Solutions Chapter 8 Human Health and Disease

MP Board Class 12th Biology Solutions Chapter 8 Human Health and Disease

Human Health and Disease NCERT Textbook Questions and Answers

Question 1.
What are the various public health measures which you would suggest as safeguard against infectious disease ?
Answer:
The common preventive measures are as follows :

  • Education: People should be educated about communicable diseases to protect, themselves from such diseases.
  • Vaccination: People should get vaccination on time to avoid infection.
  • Sanitation: The sanitation condition should be improved to avoid infection from polluted water, contaminated food, etc.
  • Eradication of vectors: The breeding places of vectors should be destroyed. adult vectors should be killed by suitable methods.
  • Sterilization: The patient’s surroundings and articles of use should be completely sterilised so as to reduce the chances of infection.

Question 2.
In which way has the study of biology helped us to control infectious diseases?
Answer:

  • Helps to properly diagnose the problem and treat them
  • Life cycle, host, reservoir, vectors, agents all can be studied and identified
  • Mechanism of transmission of pathogens to humans are known
  • Protective measures against catching the diseases are suggested.
  • Vaccines and medicines against pathogen are worked out.

Question 3.
How does the transmission of each of the following diseases take place :
(a) Amoebiasis
(b) Malaria
(c) Ascariasis
(d) Pneumonia.
Answer:
(a) Amoebiasis : Through faecal-oral route.
(b) Malaria : Through the bite of female Anopheles mosquito.
(c) Ascariasis : Through taking contaminated food and water.
(d) Pneumonia : Droplets from the sputum of the patient.

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Question 4.
What measure would you take to prevent water-borne diseases?
Answer:

  • All water resources, pools, tanks to be cleaned regularly and prevent this contamination. Only properly treated water should be added to it.
  • Use only purified and disinfected water for drinking.
  • Prevent passage of sewage and garbage into water bodies

Question 5.
Discuss with your teacher what does ‘a suitable gene’ means, in the context
of DNA vaccines.
Answer:
The term ‘suitable gene’ refers to that specific segment of DNA which forms immunogenic protein, such genes can be cloned and then integrated with vector for introducing into an individual to be immunised for certain disorder producing a particular vaccine against the pathogens.

Question 6.
Name the primary and secondary lymphoid organs.
Answer:

  • Primary lymphoid organs – Organs where B & T – lymphocytes are formed, mature, and require antigen-specific receptors – Bone marrow and thymus.
  • Secondary lymphoid organs – place or residence of nature lymphocytes – lymph nodes, spleen, tonsils, Peyer’s patches, and mucosal surfaces.

Question 7.
The following are some well-known abbreviations, which have been used in this chapter. Expand each one to its full form :

  1. MALT
  2. CMI
  3. AIDS
  4. NACO
  5. HIV.

Answer:

  1. MALT: Mucosa Associated Lymphoid Tissue.
  2. CMI: Cell-Mediated Immunity.
  3. AIDS: Acquired Immune Deficiency Syndrome.
  4. NACO: National AIDS Control Organisation.
  5. HIV: Human Immunodeficiency Virus.

Question 8.
Differentiate the following and give examples of each :
(a) Innate and Acquired immunity.
(b) Active and Passive immunity.
Answer:
(a) Differences between Innate and Acquired immunity :
MP Board Class 12th Biology Solutions Chapter 8 Human Health and Disease 1
(b) Differences between Active and Passive immunity:
MP Board Class 12th Biology Solutions Chapter 8 Human Health and Disease 2

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Question 9.
Draw a well-labeled diagram of an antibody molecule.
Answer:
MP Board Class 12th Biology Solutions Chapter 8 Human Health and Disease 3

Question 10.
What are the various routes by which transmission of Human Immuno-deficiency Virus takes place?
Answer:

  • Sexual contact with infected person.
  • Through blood transfusion.
  • By sharing infected needles in case of intravenous drug abusers.
  • From mother to child through the placenta.

Question 11.
What is the mechanism by which the AIDS virus causes a deficiency in the immune system of the infected person?
Answer:
The virus enters macrophages after getting into the body of an individual where RNA forms viral DNA by reverse transcription. The viral DNA gets incorporated in the host cell’s DNA and directs the infected cells to produce viral copies. The newly produced virus particles attack helper T-cells and thus, the number of T-cells decrease. Since, the helper T-cells are essential for functioning of immune system, the person suffers from various diseases due to dificient immune system.

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Question 12.
How is a cancerous cell different from a normal cell?
Answer:
Normal cells remain adhered to one another. They have a definite life span. As some old cells die, they are replaced by new cells which arise by cell division and differentiation. Cancerous cells:- Whenever there is a breakdown of any regulatory mechanism, a cell develops the ability to undergo uncontrolled repeated division forms a clone at cells.

There is no adherence. The cells slip past one another forming a mass of undifferentiated cells called neoplasm or tumour. Tumour results in pressing of surrounding normal cells and tissues causing discomfort and disruption of their functioning.

Question 13.
Explain what is meant by metastasis?
Answer:
Metastasis is the spread of cancerous cells through migration from one tissue to other tissue and organs resulting in formation of secondary tumour. Malignant tumour is a mass of proliferating cells called neoplastic cells. They grow rapidly and invade surrounding unaffected normal cells or tissues. Cells get sloughed off from such tumour and migrate to distant sites through blood. A new place of infection is thus, established and a new tumour is formed. This property is called metastasis.

Question 14.
List the harmful effects caused by alcohol/drug abuse.
Answer:

  • Addicts show reckless behaviour vandalism and violence. Self-confidence lost
  • Neural and neuromuscular junctions are effected.
  • Addiction disturbs peristalsis and secretion of digestive enzymes.
  • Disturbs digestive and nervous systems leads to frequent nausea and vomiting.
  • Effects on cardiovascular system.
  • Damage to liver causes cirrhosis.
  • Insufficiency develops in reproductive system.

Question 15.
Do you think that friends can influence one to take alcohal / drugs? If yes, how may one protect himself / herself from such as influence?
Answer:
Yes, friends can influence one to take drugs and alcohol. A person can take the following steps for the prevention of themself against drug abuse :

  • By avoiding under peer pressure as everyone has their own field of interest which should be respected by there teachers and family. One should not experiment with alcohal for curiosity and fun.
  • Avoid the company of friends who take drugs.
  • Seek help from parents and peers. A child should not pushed beyond his/her threshold
    limits.
  • Take proper knowledge and counselling about drug abuse. Devolve your energy in other extra-curricular activities.
  • Seek immediate professional and medical help from psychologists and psychiatrists if symptoms of depression and frustration become apparent.
  • Get rid of the problem completely and lead, perfectly normal life by increasing their will power.

Question 16.
Why is that once a person starts taking alcohol or drugs, it is difficult to get rid of this habit ? Discuss it with your teacher.
Answer:
It is difficult to get rid of this habit, because these substances are addictive and one starts having unpleasant feelings or withdrawal symptoms like nausea, vomiting, diarrhoea, shivering, muscle twitching, excessive perspiration, muscular and abdominal cramps. Mind loses control and all one can think of is taking the addictive substance. That is why resisting the temptation/pressure for the first time is the only way to avoid getting into the addictive habit and committing a slow suicide.

Question 17.
In your view what motivates youngsters to take to alcohol or drugs and how can this be avoided?
Answer:
Probably the ‘motivation’ comes from :

  • Curiosity to experience the effect.
  • Foolishness to try to prove oneself in front of peers.
  • Wrongly taking it as an excuse to escape from reality.
  • Wrong thinking that one-time ‘try’ is not going to do any harm.

But youngsters who, are strong-willed, who understand its ill effects and who are satisfied with their academic and other achievements and who don’t want to waste their precious life, don’t fall for this kind of ‘Motivation’.

Human Health and Disease Other Important Questions and Answers

Human Health and Disease Objective Type Questions

1. Choose the correct Answers :

Question 1.
Useful vaccines from the protection of Polio, Diphtheria and Tetanus :
(a)B.C.G.
(b) D.RT.
(c) M.M.R.
(d) S.T.D.
Answer:
(b) D.RT.

Question 2.
After the disease, immunity produced in the body is called:
(a) Active immunity
(b) Inactive immunity
(c) Both (a) and (b)
(d) None of these.
Answer:
(a) Active immunity

Question 3.
Cancer is related to :
(a) Irregular growth of tissues
(b) Ageing
(c) Irregular division of tissues
(d) None of these.
Answer:
(a) Irregular growth of tissues

Question 4.
Concept against smallpox vaccination is:
(a) W.B.Cs. received from animals
(b) Antigen obtained from other animals
(c) Of Antigens
(d) To weak the smallpox virus.
Answer:
(d) To weak the smallpox virus.

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Question 5.
Syphilis is a sexually transmitted disease which is caused by:
(a) Pastrulla
(b) Leptospira
(c) Treponema pallidum
(d) Vibrio.
Answer:
(c) Treponema pallidum

Question 6.
Antibody is a:
(a) A molecule which destroy a specific antigen
(b) W.B.Cs. which eats bacteria
(c) Secretion of mammalian R.B.Cs.
(d) Component of Nucleus.
Answer:
(a) A molecule which destroy a specific antigen

Question 7.
One of the form of allergy is :
(a) Asthama
(b) Yellow eyes
(c) Typhoid
(d) Mumps.
Answer:
(a) Asthama

Question 8.
AIDS virus enters in human by :
(a) Food
(b) Kiss
(c) Water
(d) Blood.
Answer:
(d) Blood.

Question 9.
Credit of vaccine goes to :
(a) Alexander Fleming
(b) Edward Jenner
(c) Louis Pasteur
(d) Robert Koch.
Answer:
(b) Edward Jenner

Question 10.
Blood cancer is:
(a) Carcinoma
(b) Sarcoma
(c) Lymphoma
(d) Leukemia.
Answer:
(d) Leukemia.

Question 11.
AIDS test is known by :
(a) ELISA
(b) Australian antigen
(c) HIV test
(d) None of these.
Answer:
(a) ELISA

Question 12.
Reason of liver cancer is:
(a) Alcohol
(b) Tobacco
(c) Both (a) and (b)
(d) None of these.
Answer:
(a) Alcohol

Question 13.
Probe is used in:
(a) Fingerprinting
(b) Segregation of gene
(c) Identification of disease
(d) All of these.
Answer:
(d) All of these.

Question 14.
Monoclonal antibodies are used in :
(a) Identification of blood group
(b) Identification of pathogen
(c) Identification of cancer
(d) All of these.
Answer:
(d) All of these.

Question 15.
Study of embryological abnormalities are called :
(a) Tricology
(b) Terentology
(c) Traumatology
(d) Termitology.
Answer:
(b) Terentology

Question 16.
The disease occurs in embryonic stage of a child due to the use of the
Thalidomide by women:
(a) Vaginal carcinoma
(b) Microcephaly
(c) Phocomelia
(d) Viralism.
Answer:
(c) Phocomelia

Question 17.
A chemical substance that causes loss of sensation is called:
(a) Antianxiety
(b) Analgesic
(c) Anesthetic
(d) Exciting (Stimulating substance).
Answer:
(c) Anesthetic

Question 18.
In which part is opium found in plant:
(a) From leaves
(b) From fruits
(c) From seeds
(d) From bark.
Answer:
(b) From fruits

Question 19.
Lethal Hallucinogen is:
(a) Opium
(b) Morphine
(c) L.S.D.
(d) Heroin.
Answer:
(c) L.S.D.

Question 20.
Stimulant found in tea:
(a) Tannin
(b) Cocain
(c) Caffeine
(d) Freak.
Answer:
(c) Caffeine

Question 21.
Which of the following is narcotic opiate:
(a) Barbiturates
(b) Morphine
(c) Amphetamine
(d) L.S.D.
Answer:
(b) Morphine

Question 22.
Name the medicine which changes our mind:
(a) Psychotropic
(b) Hallucinogen
(c) Barbiturates
(d) Stimulants.
Answer:
(a) Psychotropic

MP Board Solutions

2. Fill in the Blanks:

  1. ………………….. prescribed the germ theory of disease.
  2. ………………….. is the first human insulin which is made by genetic engineering.
  3. AIDS is ………………….. transmitted disease.
  4. Gonorrhoea is caused by …………………..
  5. ………………….. genes which is responsible for cancer.
  6. Blood cancer is known as …………………..
  7. Hepatitis disease is caused by …………………..
  8. Standard vaccine should not be …………………..
  9. Pathogens are in living condition in …………………..
  10. Cholera disease is caused by bacteria …………………..
  11. ………………….. is a good technique to kill pathogens.
  12. World Red Cross Day is celebrated on …………………..
  13. The mixture of narcotic drugs is called …………………..
  14. Benzodiazepine is ………………….. drug.
  15. World Mental Health Day is celebrated on …………………..
  16. L.S.D drug is obtained from ………………………… fungus.
  17. The medicine which releases stress and edginess without sleeping is called …………………..

Answer:

  1. Robert Koch
  2. Humulin
  3. Sexually
  4. Neisseria gonorrhoeae
  5. Oncogenes
  6. Leukemia
  7. Virus
  8. Diseased and Poisonous
  9. In living vaccine
  10. Vibrio cholerae
  11. Vaccination
  12. 8th May
  13. Cocktail
  14. Psychotropic
  15. 10th December
  16. Claviceps purpurea
  17. Tranquilizer.

3. Match the Following:
I.
MP Board Class 12th Biology Solutions Chapter 8 Human Health and Disease 4
Answer:

  1. (e)
  2. (f)
  3. (d)
  4. (a)
  5. (b)
  6. (c)

II.
MP Board Class 12th Biology Solutions Chapter 8 Human Health and Disease 5
Answer:

  1. (d)
  2. (a)
  3. (e)
  4. (b)
  5. (c).

III.
MP Board Class 12th Biology Solutions Chapter 8 Human Health and Disease 6
Answer:

  1. (d)
  2. (e)
  3. (a)
  4. (b)
  5. (c).

IV.
MP Board Class 12th Biology Solutions Chapter 8 Human Health and Disease 7
Answer:

  1. (c)
  2. (a)
  3. (d)
  4. (b)

MP Board Solutions

4. Answer in One Word/Sentence :

  1. Who has proposed germ theory of disease?
  2. Name the vector of malarial parasite.
  3. Name the genetically engineered human insulin.
  4. Give full name of HIV.
  5. Name the vaccines used for the vaccination of diphtheria, polio and whooping cough.
  6. What is the source of opium?
  7. Give two examples of stimulants.
  8. Give the names of harmful chemical compounds of tobacco.
  9. Give the name of source of LSD.
  10. Give one example of sedative drugs.
  11. Give one example of tranquilizer.
  12. Name the drugs responsible for altering mood of man.

Answer:

  1. Robert Koch
  2. Plasmodium
  3. Humulin
  4. Human Immunodeficiency Virus
  5. DPT vaccine
  6. Papaver officinarum
  7. Caffeine, cocaine
  8. Nicotin
  9. Claviceps purpurea (Fungus)
  10. Benzodiazepines
  11. Phenothiazines
  12. Barbiturates.

Human Health and Disease Very Short Answer Type Questions

Question 1.
Name the carrier of malaria parasite.
Answer:
Female Anophelies mosquito.

Question 2.
Name 2 noninfectious diseases which are the major cause of mortality?
Answer:
Hepatitis-B, AIDS.

Question 3.
Name the vaccine which prevent Diphtheria, Polio and Tetanus.
Answer:
DPT and Polio vaccine.

Question 4.
Define diseases.
Answer:
The disease is a condition when the functions of one or more organs/systems of the body are adversely affected by various symptoms.

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Question 5.
Which disease is cured by chemotherapy?
Answer:
Cancer.

Question 6.
Name 2 protozoan disease.
Answer:
Amoebiasis, malaria, Kalaazar

Question 7.
Give three examples of stimulating substances.
Answer:
Caffeine, cocaine, amiphimine.

Question 8.
Give the scientific name of the malarial parasite.
Answer:
Malarial parasite – Protozoan – Plasmodium falciparum

Question 9.
Write the source of LSD.
Answer:
Claviceps purpurea.

Question 10.
Give one example of tranquilizers.
Answer:
Phenothiazine.

Question 11.
What is the name of a drug which converts thoughts and feelings of human and causes fear?
Answer:
Psychedelic drugs.

Question 12.
Name the vector responsible for chikungunya. (Delhi 2008)
Answer:
Aedes mosquito.

Question 13.
Name the method which is used in the diagnosis of AIDS.
Answer:
ELISA Test.

Question 14.
In different parts of the country, Chikungunya is clarified. Name the carrier of this disease.
Answer:
Chikungunya is spread through bites from A. aegypti mosquitoes.

Question 15.
Name the types of Immunity.
Answer:
Immunity is two types:

  1. Innate immunity,
  2. Acquired immunity.

Question 16.
Write the full name of the pathogen that causes AIDS? (CBSE 1996)
Answer:
Human immunodeficiency virus – HIV

Question 17.
Name the types of tumours.
Answer:
Tumours are of two types :

  1. Benign and
  2. Malignant.

Question 18.
What is AIDS (HS&B 98)
Answer:
Acquired Immuno Deficiency Syndrome.

Question 19.
When the inability to open the mouth because human chewing areca nuts in betel quid or its variants (gutkha) and jaw muscles become hard. Give the name of the possible disease.
Answer:
Submucous fibrosis disease.

Question 20.
Name the full form of DPT.
Answer:
Diphtheria, Pertussis, and Tetanus.

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Question 21.
What is the side effects of cancer treatment?
Answer:
Hair falling and Anemia.

Question 22.
Name the disease in humans where the myelin sheath of nerve cells is attacked by antibodies of itself. (CBSE 2005)
Answer:
Multiple sclerosis.

Question 23.
Which plant extract is called marijuana?
Answer:
Cannabis sativa.

Question 24.
Why is antibody-mediated immunity called humoral immunity?
Answer:
Antibodies are the glycol proteins that circulate in the body fluids (humor) hence it is called humoral immunity.

Question 25.
What is the second name of Mary Mallon?
Answer:
The second name of Mary Mallon is Typhoid Mary.

Question 26.
How does colostrum provide initial protection against diseases to newborn infants? Give reason.
Answer:
Colostrum contains antibodies like IgA, which provide initial protection against diseases.

Question 27.
Which body organs are affected by Pneumonia?
Answer:
Lungs and Alveolies are affected.

Question 28.
What is the confirmation test of Typhoid?
Answer:
Typhoid fever can be confirmed by the Widal test.

Question 29.
Write the full form of LSD.
Answer:
Lysergic Acid Diethylamide.

Question 30.
What is MALT?
Answer:
MALT refers to the lymphoid tissue located with in the lining of the major tracts (respiratory, digestive, urogenital tract)

Question 31.
Name the two major groups of cells required in attaining specific-immunity.
Answer:
B-cells and T-cells.

Question 32.
Why does an AIDS patient suffer from many other infectious disease?
Answer:
Due to the reduction in a number of helper T-cells, the immune system becomes weak. Consequently, the patient suffers from infectious disease.

Human Health and Disease Short Answer Type Questions

Question 1.
Define the following:
(a) Immunity
(b) Vaccine
(c) Interferon
(d) Vaccination.
Answer:
(a) Immunity: The capacity of an organism to fight with the disease and causal organisms is known as Immunity. The Immunity is due to B and T cells.
(b) Vaccine: The chemical substances which protect our body from disease-causing organisms are called vaccines.
(c) Interferon: Interferon is an antiviral protein which is produced within animal cells due to stimulus produced after viral infection and which prevents the infection and multiplication of other viruses.
(d) Vaccination: Vaccination is the process by which resistance against a specific disease is created in any living organism.

Question 2.
Distinguish between Inborn and Acquired immunity.
Answer:
Differences between Inborn and Acquired immunity are :
MP Board Class 12th Biology Solutions Chapter 8 Human Health and Disease 8

Question 3.
What is auto-immunity?
Answer:
This is an abnormality which sometimes develops in the immune system of the body. Instead of destroying foreign molecules, it starts attacking the body’s own cells leading to serious consequences. Such diseases are called autoimmune diseases.

Auto-immune diseases depend on the type of self-antigen involved. If the self-antigens are R.B.Cs. then the body destroys its own R.B.Cs. resulting in chronic anaemia. When the self-antigen is a muscle cell, it results in the destruction of its own-muscles resulting in severe weakness, when the self-antigens are liver cells, it results in chronic hepatitis.

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Question 4.
Write the scientific names of two helminthiasis that are pathogene to man. Name the disease caused by them.
Answer:

  • Ascaris lubricoides causes Ascariasis
  • Wuchereria bancroffi causes filariasis or elephantiasis.

Question 5.
What is B-cells and T-cells? Explain it
Answer:
B-lymphocytes or B-cells produce an army of protein called antibodies in blood. In response to pathogens, T-lymphocytes or T-cells help B-cells to produce antibodies immune response are produced by these two types of lymphocytes.

Question 6.
Which types of diseases are protected by D.P.T. vaccine? Write the name of pathogens for each disease.
Answer:
D.P.T. vaccine is protect three types of disease :

(i) Diphtheria
(ii) Pertussis
(iii) Tetanus.
Name of the Pathogens:
MP Board Class 12th Biology Solutions Chapter 8 Human Health and Disease 9

Question 7.
What is Eugenics?
Answer:
Eugenics: The branch of biology which deals with the study of improvements of human race is called eugenics.
Importance:
1. Development of selective reproduction in similar species.
2. Transfer of genetic materials in various organisms.
3. Development of GM food and GM crops.
4. Gene cloning.
5. Gene therapy, etc.

Question 8.
Name and explain the type of barrier of the innate immune system, which involves.
Answer:
Cellular barrier
This barrier involves certain types of

  • Polymorphs nuclear leucocytes
  • Monocytes
  • Natural killed cells
  • Macrophages.

Question 9.
What is Drug addiction? What are its causes?
Answer:
Addiction is most common problem of our youths because they start to take different types of drugs and alcoholic beverages due to various reasons. It makes them habitual and dependent on them. Addiction is the habitual, psychological and physiological dependence on a substance or practice which is beyond voluntary control. A person who is habituated to a substance or a practice especially harmful one, is called drug addiction.
Its causes are :

  • Curiosity
  • Fun and stimulation
  • Will of doing more work
  • Feeling of freeding
  • Temporary escape from life problems.

Question 10.
Write down the differences between Sedative and Tranquilizer.
Answer:
Differences between Sedative and Tranquilizer:
MP Board Class 12th Biology Solutions Chapter 8 Human Health and Disease 10

 

Question 11.
Give the name of source of LSD. Give its effects also.
Answer:
LSD (Lysergic Acid Diethylamide): It is a crystalline amidated alkaloid which is obtained from the sclerotium of ergot fungus Claviceps purpurea, pathogen of ergot disease of rye.
LSD causes horrible dreams, hallucinations, chronic psychosis and damage the brain. LSD was tried as treatment for alcoholism, neurosis and cancer patients. LSD brings about chromosomal and foetal abnormalities. Pathological condition caused by LSD abuse or by eating grain affected by ergot is called ergotism.

Question 12.
Describe the cell mediate immunity.
Answer:
Cell mediate immune response is effected by T-lymphocyte. These are two types of T- lymphocytes.

  • Cytotoxic or killer T- cells, which kill the antigens in a variety of mechanisms.
  • Helper T-cells slimulate the B-lymphocyte to produce antibodies. This immunity is responsible for rejection of transplants.

Question 13.
Write withdrawal symptoms of addiction.
Answer:
Withdrawal symptoms from Addiction: When a drug-dependent person fails to get the drug, he feels severe physical and psychological disturbances. These are called withdrawal symptoms. It includes tremors, nausea, vomiting, weakness, insomnia, anxiety run fits, decreased appetite, restlessness, elevated blood pressure, rapid heartbeat and epilepsy. These symptoms indicates that the body of addict person is unable to further use of intoxicant and they should stop it immediately.

Question 14.
Explain metastasis. Why is it fatal?
Answer:
The rapid growth of cancerous tumour causes overcrowding and disruption of normal cells. It extends to neighbouring tissues. In the last stage, bits of tumour tissue breakoff and are carried by the circulating blood or lymphs to other parts of the body, where they invade new tissues and start new tumors called secondary tumors. This property is called metastasis. It is fated due to increasing interference with the body’s life processes.

Question 15.
What are sedative? What are its types? Write its effect.
Answer:Sedative : Drugs which directly depress the brain and central nervous system are included in this group. They make the body free from anxiety and lethargic. The excessive use leads to sleep. Sleep causing drugs are also called Hypnotics.
It is of two types :

  1. Barbiturates and
  2. Benzodiazepines.

1.  Barbiturates: It is a sedative and tranquilizer. It suppresses brain’s activity and creates a feeling of relaxation, drowsiness and sleepiness.
2. Benzodiazepines: These drugs are commonly prescribed to help relieve anxiety in people who have anxiety disorder or another mental illness where anxiety is a symptom. They are very addictive.

MP Board Solutions

Question 16.
What are lymph nodes? What is their function in our immune system?
Answer:
Lymph nodes are small solid structures located at different points along the lymphatic system. They serve to tray the microbes and other antigens. These antigens trapped in the lymph nodes are responsible for the activation of lymphocytes to cause the immune system.

Human Health and Disease Long Answer Type Questions

Question 1.
What is cancer? Write the names of two types of cancer and causes of cancer.
Answer:
Cancer: When tumours are formed due to the unorganized and uncontrolled division of cells, then it is called cancer.
Types of Cancer: Cancer is not a single disease but a complex of many diseases. Today about 200 distinct types of cancer have been recognized.

These are grouped into four main types:

  1. Carcinomas
  2. Sarcomas
  3. Lymphomas and
  4. Leukemias.

1. Carcinomas: The tumours which are made up of epithelial cells of ectodermal or endodermal origin are called carcinomas, e.g., solid tumours in nerve tissues and in tissues of body surfaces or their attached glands. It includes breast, skin, cervical and brain carcinomas.

2. Sarcomas: Hie tumours which are made up of connective tissue cells of mesodermal origin are called sarcomas. e.g., solid tumours growing from connective tissues, bones, cartilages and muscles. It constitutes only about 2% of human cancers.

3. Lymphomas: Cancers in which there is excessive production of lymphocytes by the lymph nodes and spleen are called lymphomas, e.g., Hodgkin’s disease. It constitute about 5 % of human cancers.

4. Leukemias: It is cancer of blood characterized by excessive number of W.B.Cs. (or leucocytes) in the blood (neoplastic growth). These cells invade into bone-marrow, lymph nodes and the spleen. It is more frequent in the children of age group 5 to 7 years but it can occur at any age. Acute leukemia causes death. It has no sure remedy. It constitutes about 4% of human cancers.

Causes of Cancer: Physical and chemical factors which cause cancer are called carcinogens. The main causes of cancer are as follows:

  • Smoking causes mouth and lung cancer.
  • Radiation, such as X-rays, ultraviolet rays and other ionizing radiations causes cancer.
  • Viruses may cause cancer.
  • Chemical substances such as Nicotine, caffeine, products of combustion of coal and oil, polycyclic hydrocarbons may cause cancer.

Symptoms of Cancer: There are some symptoms of cancer which must be kept in mind:

  • Any lump or thickening in the tissue especially in breast, tongue or lip.
  • A wound that is not healing.
  • Any sudden change in mole or warts.
  • Persistent indigestion and difficulty in swallowing things.
  • Regular cough and hoarseness in sound.
  • Unusual weight loss.
  • A change in bowel habits.
  • Any ulcer that does not get well.
  • Bleeding in the vagina at times other than menstruation.
  • Non-injury bleeding from the surface of the skin, mouth, or any other opening of the body.

MP Board Solutions

Question 2.
Justify the following statements
(i) Smoking leads to a deficiency of oxygen in the body tissue.
(ii) Cancer patients are administered – interferon
(iii) Chewing of tobacco causes an increase in blood pressure.
Answer:
(i) Smoking increases the carbon monoxide (CO) content in blood and reduces the concentration of haem-bound oxygen hence there is deficiency of oxygen in the body tissues.

(ii) Tumor cells avoid detection and destruction by our immune system. Interferon-like biological modifiers activate the immune system and help in destroying the tumor cells.

(iii) By chewing tobacco the nicotine reaches the blood and stimulates the adrenal glands to release adrenaline and noradrenaline, both these hormones increases the blood pressure.

Question 3.
What is immune system? Describe various components of immune system of man and its role.
Answer:
The Immune system or Immunity (A Specific Defence Mechanism) : The ability of an organism to resist the pathogen or development of disease resistance is known as immunity and the study of immunity is called immunology, while the infected person with no disease is called immune. The most peculiar characteristic of immune system is that it can differentiate the self (body’s own cells) and non-self (foreign microbes).

Cells of the Immune System : Lymphocytes are the type of W.B.Cs. or Leucocytes which are chief cells of immune system of body. There are two types of lymphocytes that promote cellular immunity and humoral immunity. Both of these types of lymphocytes are derived from lymphocyte stem cells in the bone-marrow in the embryo.

1. T-cells of lymphocytes : These cells eventually migrate to the lymphoid tissue. Before doing so, the lymphocytes first migrate to thymus gland and are processed in the gland, hence called T-lymphocytes or T-cells. These are responsible for cellular immunity. There are following types of T-cells :

Killer T-cells : Killer T-cells or KT-cells directly attack and destroy antigen. In doing so, they move to the site of invasion and produce some chemical that attracts and stimulate phagocytes to feed more voraciously on antigen.
Helper T-cells : Helper T-cells or HT-cells stimulate B-cells to produce more antibody.
Suppressor T-cells: Suppressor T-cells or ST-cells keep entire immune system to attack on the own body cell.

Mode of action of T-cells to antigens : T-cells are antigen specific (each T-cell recognizes a specific antigen and different types of T-cells are stimulated by different types v of antigens). When a T-cell is stimulated by specific antigen, T-lymphocytes divide ripidly to form a clone of T-cells called lymphoblasts. T-cells live for 4-5 years or even longer. T- cells of a clone are morphologically similar but they perform different functions. According to their functions, their are three classes of T-cells, i.e., killer T-cells, helper T-cells and 1 suppressor T-cells.

2. B-cells of lymphocytes: The other population of lymphocytes which produces antibodies are processed in some unknown area, possibly liver or spleen. This population ‘ was firstly discovered in birds in which processing occurs in the bursa of fabricus, a structure not found in mammals. For this reason they are called as B-cells or B-lymphocytes. They are responsible for humoral immunity.

Mode of action B-cells to antigens: Once a B-cells is activated by the antigen, it multiplies very fast and forms a clone of plasma cells. Most of these produce antibody at a tremendous rate of 2,000 molecules per second. These antibodies circulate in the lymph to fight the antigen. So, forming humoral immune system. B-cells are short lived and are replaced by new cells from the bone-marrow after every few days.
The capacity of B-cells to produce specific antibodies is acquired during its development and maturation.

MP Board Solutions

Question 4.
Describe the harmful effects of tobacco smoking.
Answer:
Effect of chewing and smoking Tobacco: The chewing and smoking of tobacco affects us in the following ways :

  • It affects the route of the transfer of nerve impulse and central nervous system. In low concentration nicotine stimulates the conduction of nerve impulse but long-term use reduces the activity of nervous system.
  • Nicotine stimulates the release of adrenaline leading to high blood pressure. Increased blood pressure due to smoking enhances the risk of heart diseases.
  • It retards foetal growth in pregnant women.
  • The smoke of tobacco contains aromatic hydrocarbons and tar along with carbon monoxide (CO). Carbon monoxide reduces the oxygen-carrying capacity of the blood. Hydrocarbons induces cancer. Due to these reasons tobacco chewing person suffer from mouth cancer and smokers suffer from throat and lung cancers.
  • The use of tobacco in any form stimulates the secretion of saliva and gastric juices due to which acidity is increased in stomach. It may cause ulcers in the wall of stomach. The absorption capacity of mucous membrane of stomach also decreases. Thus, a person get suffered from hyponutrition, loss of appetite and constipation.
  • Smoking also affects the activity of kidneys.
  • Nicotin relaxes the muscular and skeletal tissues due to which person becomes weak.
  • Long-term smoking may also cause diseases like bronchitis and Emphysema.
  • Smoking reduces immunity of the body.
  • Lips of smokers may become dark coloured. Teeth and fingers get stained. The breath becomes foul.

Question 5.
What are the causes of addiction?
Answer:
Causes of addiction are : Young peoples take drugs and alcoholic beverages and other intoxicans substances because of the following reasons:

  • Curiosity: It is one of the most important cause of addiction because curiosity is generated among young peoples due to the advertisement of drugs in newspapers and other means of communication. So, that they take them for fust time and then became habitual.
  • Fun and Stimulation: Some drugs are stimulative in nature. These drugs are used to increase body power but regular use of these drugs make them habitual. These drugs cause physical and mental weakness.
  • Will of doing more work: It is believed that the use of intoxicating substances increases die capacity of the body and person is able to do more physical and mental work. But it is not true because these substances increases mental and physical fatigues.
  • Feeling of freedom.
  • Inability to face problems of life.
  • Encouragement or Pressure by friends.
  • Temporary escape from life problems.
  • Mental relaxation.
  • Relax from pain.
  • Feeling of freedom, etc.

MP Board Solutions

Question 6.
Explain the different methods of detecting cancer.
Answer:
Cancer can be detected by

  • Biopsy and histopathological studies of the tissue
  • Using antibodies against cancer-specific antigens
  • Blood and bone marrow test to check the count of WBC and RBC
  • Use of C T scans (Computerised tomography) MRI (magnetic resonance imaging) and X-rays to detect the cancer of internal parts.
  • Applying principles of molecular biology to detect the genes in individuals with inherited susceptibility to cancer.

MP Board Class 12th Biology Solutions

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