SUMMATIVE ASSESSMENT WHY DO WE FALL ILL
Class IX
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Summative Assessment―Why Do We Fall Ill
Class 9
Basic conditions for good health: i ii iii iv v vi
Proper balanced and nutritious diet Personal hygiene Clean environment & surrounding Healthy air, no pollution in the surrounding Regular exercise Proper rest
Disease When the body is not at ease i.e., comfortable then it is said to have a disease. When there is a disease, the functioning or appearance of one or more systems of body changes. Depending on the duration―disease is classified as acute or chronic Acute disease Diseases that the last for only short period of time. e.g., headache, common cold etc. Chronic disease Diseases that last for long time, are elephantiasis, tuberculosis etc.
called chronic
diseases e.g.,
Causes of diseases Immediate cause and contributory cause. Immediate cause The organisms that enter our body and causes disease is called immediate cause―for example virus, bacteria, protozoa etc. Contributory cause The secondary factors which led these organisms enter our body are called as contributory cause. For example dirty water, unclear surrounding, contaminated food, improper nourishment, poverty, poor standard of living etc. Diseases may be due to Infections and non-infectious causes. Infectious causes Diseases where microbes are the immediate causes are called infectious diseases. The infectious spread from are person to another. Non―infectious causes Some diseases that does not spread in the community, but remains internal are called non―infectious diseases. Example: cancer, genetic abnormalities, high blood pressure etc. Infectious diseases (communicable diseases) When a disease causing organism enters our body it causes infection, it multiplies and grows in the body called host and micro―organisms multiplies in the host body. ANNANT CLASSES
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Summative Assessment―Why Do We Fall Ill Cause of Infections
Class 9 Diseases
Bacteria
Tuberculosis, tetanus, typhoid, cholera
Virus
AIDS, polio, chicken-pox, rabies, measles
Fungi
Skin diseases, food poisoning
Protozoan
Malaria, amoebiasis, kala-azar
Worm
Filariasis
Diseases spread through (a) Air
(b) Food & water
(c) Contact
(d) Body fluids
Causes air borne diseases due to bacteria virus, e. g., common cold, influenza, measles, tuberculosis. Is caused due to contaminated food and water that contains bacteria virus, worm. Example: cholera, typhoid, hepatitis. Many diseases spread by contact of infected person with the healthy person. Example: fungal infection, scabies etc. Like blood, semen, mother milk when infected can also cause disease. Example: AIDS.
TYPES OF DISEASES Diseases are broadly grouped into two categories: ◊ ◊
Congenital diseases Acquired diseases
Congenital diseases These diseases are those which are present since birth. Such diseases are caused due to a genetic abnormality of malfunctioning of any organ system. These diseases may be inherited. Acquired diseases These diseases are those which develop after birth. These can be broadly classified into two types » »
Communicable or infectious diseases Non-communicable or non-infectious diseases
Communicable or infectious diseases These diseases communicate from an unhealthy or diseased person to a healthy person. They are caused by some biological agents or micro-
organisms (pathogens) such as viruses, bacteria, fungi, protozoa or helminths (worms). The causative organism of the disease can spread form one person to another through contact, water, air, food, etc. Examples: Malaria, dengue etc. ANNANT CLASSES Summative Assessment―Why Do We Fall Ill
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Non-communicable (non-infectious) diseases These diseases are not spread from an infected person to a healthy person. They are caused due to some specific factors such as malfunctioning of some vital organs, deficiency of nutrients, etc. Examples: Diabetes, arthritis, heart diseases, cancer etc. Non-communicable diseases can be further divided into: ◊ ◊ ◊
Degenerative diseases Deficiency diseases Allergies
Degenerative diseases These diseases are caused due to malfunctioning of the important body organs. Example: osteoporosis, kidney failure, myopia, arthritis etc. Deficiency diseases These diseases are caused by deficiency of nutrients like proteins, minerals, vitamins etc. Examples: marasmus, kwashiorkor, anaemia, goiter, beriberi, pellagra etc. Allergies Allergies is caused due to the hypersensitivity of the body to foreign substances like pollen grains, dust, silk, nylon, egg, fish, certain drugs etc. The substances due to which allergy is caused are allergens. Examples: asthma, bronchitis, skin allergy etc. Vectors The organisms that spread a disease by carrying pathogens from one place to another called vector. Example: mosquitoes, are vectors that carry pathogens like protozoa. Antibiotics These are chemicals (medicine, drugs) that block biochemical pathways important for bacteria. They are used for diseases caused by bacteria. Inflammation When an active immune system release many cells to the affected tissue to heat-off the disease-causing microbes is called inflammation. Local effects caused on body due to inflammation are―swelling, pain, fever and redness. MEANS OF SPREAD Infectious diseases spread from an infected person to a healthy person in the following ways.
ANNANT CLASSES Summative Assessment―Why Do We Fall Ill
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Modes of transmission of communicable diseases │ │ │ Direct transmission indirect transmission │ │ │Direct contact │By vectors │Droplet infection │Waterborne │Contact with soil │Airborne │Animal bite │Object-borne │Tran placental transmission │Dirty hands & Fingers DIRECT TRANSMISSION The pathogens of certain diseases react and infect a healthy person directly without an intermediate agent. It can take place by various means. ●Direct contact: between the infected person and the healthy person. Diseases like small pox, chicken pox, syphilis, gonorrhoea, spread through direct contact through which syphilis and AIDS are caused. ●Droplet infection: Droplets are air borne. The infected person throws out tiny droplets of mucus by coughing, sneezing, spitting or even talking. These droplets may be containing pathogens (virus, bacteria). By inhaling the air containing the droplets, a healthy person may get the infection. Diseases like common cold, pneumonia, influenza, measles, mumps, tuberculosis etc are spread by droplets infection. ●Contact with soil: contaminated with diseases causing viruses, bacteria etc. The bacteria responsible for tetanus enter the human body from the soil. ●Animal bite: Viruses of rabies are introduced through the wound caused by the bite of rabid animals, especially dogs. The virus is present in the saliva of the rabid animal. ●Through placental transmission: this may pass from the mother’s body to the foetus through placenta. For example―virus of German measles, AIDS virus etc. INDIRECT TRANSMISSION
The pathogens of certain diseases reach the human body through some intermediate agents. It can take place by various means, which are as follow: ●By vectors: Houseflies, mosquitoes and cockroaches which take up the pathogens from the reservoir of infection pass it to healthy people. ANNANT CLASSES
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Summative Assessment―Why Do We Fall Ill
Class 9
These are intermediaries and are called as vectors. For examples―houseflies carry the causative organisms of cholera, typhoid, dysentery and tuberculosis on their legs and mouthparts from the faeces and sputum to food and drinks and contaminate them. ●Airborne: The pathogens may reach the humans with air and dust. The epidemic typhus spreads by inhaling of dried faeces of infected lice. ●Waterborne: Diseases spread also through water contaminated with microbes. For examples―contaminated water may contain excreta from someone suffering from infectious gut disease, such as cholera. When this water mixes with the water used by several persons for drinking, the cholera causing microbe will enter the new hosts and cause diseases in them. ●Object-borne: Many diseases are transmitted through the use contaminated articles, such as handkerchiefs, towels, utensils, toys etc.
of
●Dirty hands and fingers: are also sources of infection for various digestive and respiratory diseases. HOW AIDS DOES SPREADS? AIDS spreads through: i ii iii iv v
Sexual contact with infected person. Transfusion of blood infected with the HIV. Use of HIV infected needle for injections. HIV infected mother to foetus (then to newly born infants) HIV infected mother to baby through breast feeding.
PREVENTION OF AIDS ● ● ● ●
Peoples should be educated about AIDS. Only disposable needles and syringes should be used. Routine screening may be done of blood donors, organ donors, donors of growth hormones. Before receiving blood, it must be screened for HIV.
AIDS does not spread through casual contact such as handshake, or hugs, or sports like wrestling or by any other means in which we touch each other socially.
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