WHY DO WE FALL ILL class 9 biology , 14th chapter

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NCERT BOOK CHAPTER 14 OF SCIENCE CLASS 9TH

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WHY DO WE FALL ILL class 9 biology , 14th chapter

  1. 1. 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.
  2. 2. 2) Differences between Healthy and Disease free :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.
  3. 3. 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
  4. 4. 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.
  5. 5. Proper sanitation and disposal of faecal matter prevents infection . TYPHOID. Typhoral oral vaccine also prevents typhoid. TAB vaccination provides immunity for 3 years .
  6. 6. 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 ,kalaazar .Worms cause intestinal diseases as well as 
  7. 7.  –These i. ii. iii. iv. v. vi. are not spread to other persons. These are of following types:Deficiency- caused deficiency of nutrients and hormones. E.g. diabetes , scurvy. Allergic – when body is hypersensitive to foreign elements. E.g. asthma Cancer- uncontrolled growth of certain tissues. Mental disorder- depression ,anxiety etc. Addiction :- alcohol, drugs. Degenerative- malfunctioning of important organs .E.g. heart diseases.
  8. 8.  Viral :- influenza , chickenpox , small pox ,common cold, dengue fever and AIDS
  9. 9.  Fungal :- ringworm etc.
  10. 10.  Bacterial :- cholera ,typhoid , tuberculosis and anthrax .
  11. 11. Protozoan :- malaria , kala-azar
  12. 12. 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.
  13. 13. 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 mosquito Symptoms –fever at interal,weakness . Cancer Cause- abnormal and uncontrolled growth of cells Risk factors – tobacco, alcohol, high fat diet , smoking. Hypertension Cause- blood pressure levels, stress, tension , salt intake ,fat intake(large)
  14. 14. 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.
  15. 15. Picture of staphylococci ,the bacteria which can cause acne .
  16. 16. Picture of an adult roundworm (Ascaris lumbricoides is the technical name ) From the small intestine .The ruler next to it shows
  17. 17. 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 been An antibiotic is a selective poison. It hasin common. that it will for the desired bacteria, chosen so All viruses , kill example ,live inside host cells ,whereas bacteria very rarely do. 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 
  18. 18.   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.
  19. 19. 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.
  20. 20.  Animals to people: Wash your hands after petting animals or touching any surfaces they come into contact with.
  21. 21. 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
  22. 22.  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:
  23. 23.   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.
  24. 24.   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.
  25. 25.   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.
  26. 26. Organ-specific and tissue-specific manifestations
  27. 27. Microbes which enter our body are Likely to go to different Sites in our body such as :-
  28. 28. TYPHOID BACTERIA
  29. 29.  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 ( 1: (a) diphtheria 2: (c) long term affect on our health
  30. 30.  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 intestine 4: (d) lungs 5: (b) Influenza
  31. 31.  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) vector 8: (a) epidemic diseases
  32. 32.  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 these 10: (a) live outside the host cells 11: (d) tuberculosis
  33. 33.  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) Cholera 13: (b) protozoa 14: (a) it develops resistance against the pathogen attack
  34. 34.  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) diarrhea 16: (b) Rickets
  35. 35. 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 arei. 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.
  36. 36. 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 i. ii. iii. iv. v. List the causes of diseases . Infection Poor health Lack of proper and sufficient food Lack of public services Genetic differences . List four diseases caused by viruses? Ans- diseases caused by viruses are – • Common cold • Influenza • Dengue fever • AIDS
  37. 37. What are the difference between communicable and non- communicable diseases? COMMUNICABLE(INFECTIOUS ) DISEASES NON-COMMUNICABLE (NONINFECTIOUS )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.
  38. 38. 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.
  39. 39. Give causes and remedy of i) Hepatitis ii)AIDS iii)Malaria Ans Causes i) Hepatitis is caused by virus ii) AIDS is caused by HIV. iii) Malaria is caused by Plasmodium(Protozoan microbe) Spread by bite of female Anopheles mosquito. Remedy - Hepatitis A and B vaccination (preventive measure) - Avoid eating stale food . - Avoid any type of infection - Now anti – viral drugs that keep HIV infection under control are available . -Avoid breeding of mosquito in stagnant water ditches ,ponds,etc. - Consult doctor for treatment . -Use mosquito repellents.
  40. 40. 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.

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