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Premium member Presentation Transcript PowerPoint Presentation: SCIENCE PROJECT WORK By Divya Gupta (IX A)Why Do We Fall Ill: Why Do We Fall IllPowerPoint Presentation: Introduction The cells are the “basic units of living beings”, which are made of a variety of chemical substances like the proteins, carbohydrates, fats or lipids etc. The cells move during development and differentiate into specific cells like muscles. The cells perform vital functions in body. If the functioning of cells and tissues is prevented due to some reason, it would cause malfunctioning of body.PowerPoint Presentation: Health and its Failure 1. The Significance of ‘Health’ - The word ‘health’ concerns with wellness. Health always implies the idea of ‘being well’ as effective functioning of body and our healthy attitude also. ‘Health’ is stated as “a state of being well enough to function well physically, mentally and socially”. 2. Personal and Community Issues both Matter for Health - As we know the definition of health. So, it cannot be achieved entirely on our own. It would depend on our surroundings, or the environment.PowerPoint Presentation: The human beings live in societies. Our social environment is an important factor in our individual health. Our physical environment is decided by our social environment. For example, the garbage may get collected in near houses. If it is not disposed off, it would cause the possibility of poor health. So, public cleanliness is important for individual health. Following are the aspects which need to be followed for individual good health: ( i ) A person must take proper diet to maintain good health. (ii) Clean habits make a person healthy. (iii)Persons should use clean water. Hands should be washed before eating. (iv) Good economic conditions and jobs are needed for individual health also.PowerPoint Presentation: (v) Social equality and harmony are therefore necessary for individual health. 3. Distinction between ‘Healthy’ and ‘Disease-free’ - The word ‘dis-ease’ means “disturbed ease”. Disease means ‘being uncomfortable’ and uneasiness. So disease is opposite of ease or just opposite of health. A person is called healthy if he has no symptom of sickness or illness and anxiety. His all body or its parts are functioning well. He is mentally fit. He is socially aware. He works happily and can take active part in social activities.PowerPoint Presentation: Disease and its Causes 1.What Does Disease Look Like?- The disease is “an impairment of the normal state of an organism that disturbs the performance of vital functions”. Many tissues in the body, make up physiological systems or the organ systems and each of them has specific organs as its parts are to perform the particular functions. During disease, the functioning or the appearance of one or more systems of the body may change. These changes give rise to symptoms and signs of the disease. The symptoms of disease are “things we feel as being ‘wrong’”.PowerPoint Presentation: Signs of disease are what physicians or doctors look for on the basis of symptoms of a patient. Signs will give a little more definite indication of the presence of a specific disease. The physicians or doctors may get laboratory tests. These tests are done to pinpoint the disease further. 2.Acute and Chronic Diseases- Manifestations of disease are different as they depend on many factors like duration. Some diseases last for only very short periods of time e.g., common cold. Some diseases may last for a lifetime e.g., infection causing elephantiasis is very common in certain parts of India. An acute disease is identified as one that comes on rapidly and could be dangerous or fatal, but a chronic disease lasts for a long time.PowerPoint Presentation: 3.Chronic Diseases and Poor Health- The acute and chronic diseases are two types of diseases that have different effects on health. A disease causing poor functioning of certain part of our body would affect our general health. It is due to all functions of the body which are essential for general health. An acute disease lasts for few days and is over very soon. Therefore, it does not cause major effects on our general health, e.g., in cough and cold, we get better and become well within a week. A chronic disease causes major effects on our body, e.g., when we get infected with a chronic disease like tuberculosis of our lungs, we lose weight and feel tired all the time and these are long term effects of TB. Therefore, the chronic diseases have very drastic long-term effects on our health in comparison to the acute diseases.PowerPoint Presentation: 4.Causes of Diseases- The virus may come from unclean drinking water. It may be due to lack of good nourishment. It may be genetic difference to suffer from loose motions when exposed to a virus. The public services may be poor. 5.Infectious and Non-infectious Causes- Immediate causes of disease belong to two distinct types – infectious and non-infectious agents. Infectious agents are microbes / micro-organisms. The diseases where microbes are immediate causes are called infectious diseases. Microbes can spread in a community.PowerPoint Presentation: There are some diseases which are not caused by infectious agents. Their causes vary. The causes are mostly internal, non-infectious causes. For example, some cancers are caused by genetic abnormalities and high blood pressure may be caused by excessive weight and lack of exercise. Ways in which diseases spread, the ways in which diseases can be treated, and ways in which they can be prevented at community level may be different for different diseases. It depends on immediate causes either infectious or non-infectious.PowerPoint Presentation: Infectious Diseases 1.Infectious Agents- The disease-causing organisms may be virus, bacteria, fungi, single-celled protozoans as well as multi-cellular organisms, e.g., various types of worms. Some diseases are caused by viruses. They are common cold, influenza, dengue fever and AIDS. Diseases like typhoid fever, cholera, tuberculosis and anthrax are caused by bacteria. Many common skin infections are caused by different kinds of fungi. Protozoan microbes cause many familiar diseases such as malaria and kala-azar. We have also come across intestinal worm infections, and the diseases such as elephantiasis caused by different species of worms.PowerPoint Presentation: The category of infectious agent is important to decide about the treatment of disease, which may have several common biological characteristics. All viruses live inside host cells. Viruses, bacteria and fungi multiply very quickly, but the worms multiply very slowly. It means that “many biochemical processes inside their cells are similar”. Consequently the drugs that block one of these biochemical mechanisms in one member of the group will be effective against several other members of the group. The same drug will not work against a microbe belonging to a different group. For example, antibiotics commonly block biochemical pathways essential for bacteria. Several antibiotics work against many species of bacteria rather than simply working against one. The viruses do not use these pathways. Therefore, antibiotics do not work against viral infections.PowerPoint Presentation: 2.Means of Spread- Many microbial agents may commonly move from an affected person to someone else in a variety of ways. They can be ‘communicated’. Thus these are also termed as the communicable diseases. ( i ) By Air – They occurs through the little droplets thrown out by an infected person who sneezes or coughs. A person standing close by can breathe in these droplets and microbes get a chance to start a new infection. Examples are common cold, pneumonias, tuberculosis, influenza (flu), measles and mumps etc. The more crowded our living conditions are, the more likely it is that such air-borne diseases will spread.PowerPoint Presentation: (ii) By Water – They may get into our body through water and food. It happens when the excreta from someone suffering from an infectious gut disease, e.g., cholera. Cholera-causing microbes will enter new hosts through water they drink and cause disease in them. Such diseases are much more likely to spread in the absence of safe drinking (potable) water. (iii) By Close Physical Contacts – Sexual act is one of the closest physical contacts. Syphilis or AIDS are transmitted by sexual contact from one partner to the other. They are not spread by casual physical contacts like handshakes or hugs or sports such as wrestling, or by any other way when we touch each other socially. AIDS spread by sexual contact with infected persons, or through transfusion of infected blood and through infected needles used for injections. Children of AIDS get infection from their mother’s blood.PowerPoint Presentation: (iv) By Vectors / Carriers – Several diseases are transmitted by some animals which carry the infecting agents from a sick person to another potential host. These animals are intermediaries and are known as vectors, e.g., mosquitoes. In many species of mosquitoes, the females need highly nutritious food in the form of blood to lay mature eggs. 3.Organ-specific and Tissue-specific Manifestations- Several species of microbes have evolved to home in on various parts of body. It is related to their point of entry. When they enter from air via nose, they may go to lungs, e.g., bacteria cause tuberculosis. When they enter through mouth, they may be in gut lining, e.g., typhoid-causing bacteria. Some may go to liver, e.g., viruses cause jaundice.PowerPoint Presentation: The infection of HIV, comes into our body through the sexual organs. It would spread to lymph nodes all over the body. Malaria-causing microbes enter the body through a mosquito-bite. They go to the liver, and then to the red blood cells. The virus causing Japanese encephalitis, or brain fever, will similarly enter through a mosquito-bite. It infects the brain. Signs and symptoms of a disease depends on tissue or organ which the microbe target. When the lungs are the targets, the symptoms are cough and breathlessness. If liver is the target, there will be jaundice. If brain is targeted, the symptoms will be headache, vomiting, fits and unconsciousness.PowerPoint Presentation: The tissue-specificity of infection causes very general-seeming effects, e.g., in HIV infection, HIV virus goes to the immune system and damages its function. The effects of HIV-AIDS are because the body can no longer fight off the many minor infections. A minor gut infection can produce major diarrhoea with blood loss and other infections kill people suffering from HIV-AIDS. Most of the common effects depend on the fact that “body’s immune system is activated in response to infection”. An active immune system recruits many cells to affected tissue to kill off disease-causing microbes. It is termed inflammation. These are local effects like swelling, pain, fever.PowerPoint Presentation: The severity of disease manifestations depend on the number of microbes in the body. When number of microbes is very small, disease manifestation are minor / unnoticed. When numbers of same microbe are large, the disease can be severe enough to be fatal. Immune system is a major factor which determines the number of microbes surviving in the body. 4.Principles of Treatment- There are two ways to treat an infectious disease: ( i ) To reduce the effects of a disease. (ii) To kill the cause of a disease. For the first case, treatment provided would reduce the symptoms that are usually due to inflammation, e.g., we can take medicines to bring down fever, to reduce pain or loose motions. The bed rest conserves our energy.PowerPoint Presentation: The symptom-directed treatment by itself would not make the infecting microbe go away. It is not sufficient to cure a disease. We should kill off the microbes causing that disease. To kill microbes we use certain medicines. Different categories of microbes are viruses, bacteria, fungi or protozoa. Each of these groups of organisms have some essential biochemical life processes that is peculiar to that group and not shared with the other groups. These processes can be pathways for the synthesis of new substances or respiration. Our cells may make new substances by a mechanism different from that used by bacteria. A drug that block the bacterial synthesis pathway without affecting our own, e.g., antibiotics. There are drugs which kill protozoa, e.g., the malarial parasite.PowerPoint Presentation: Making anti-viral medicines is more harder than making anti-bacterial medicines. Viruses have few biochemical mechanisms of their own. They enter the cells and use our machinery for their vital processes. It means that “there are relatively few virus-specific targets to aim at”. There are now effective anti-viral drugs, e.g., some drugs keep HIV infection under control. 5.Principles of Prevention- There are three limitations of this approach to deal with infectious disease: ( i ) When once somebody has a disease, his body functions are destroyed and may never recover completely. (ii) Treatment would take time. It means that “someone suffering from a disease is likely to be bedridden for sometime” even if we give him proper treatment.PowerPoint Presentation: (iii) The person suffering from an infectious disease may act as source from where infection may spread to other persons. It leads to multiplication of above difficulties. So, “prevention of disease is better than cure”. There are two ways to prevent infection: ( i ) the general way, and (ii) the specific way, to each disease. ( i ) The General Ways – These ways are mostly connected to preventing exposure. For airborne microbes, we can prevent exposure by providing living conditions that are not over-crowded. For water-borne microbes, we can prevent exposure by proving safe drinking water by treating it to kill any contamination. For vector- borne infections, we can provide clean environments. It would not allow mosquito breeding. Public hygiene is one basic key for prevention of infectious diseases.PowerPoint Presentation: We face with infections daily, e.g., if somebody is suffering from cold and cough in our class, it is likely that children sitting around him will be exposed to the infection. All of them do not actually suffer from the disease due to the immune system of body. Immune system of our body fights off with microbes. Some cells are specialized in killing infecting microbes. These cells go into action each time when infecting microbes enter the body. The immune cells manage to kill off the infection long before it assumes major proportions. When the numbers of the infecting microbes are controlled, the manifestations of disease would be little.PowerPoint Presentation: An infectious disease represents a lack of success of the immune system. Functioning of the immune system, like any other system in our body, will not be good if proper and sufficient nourishment and food is not available. Therefore, the second basic principle of prevention of infectious disease is “the availability of proper and sufficient food for everybody”. (ii) The Specific Ways – These are related to a peculiar property of the immune system that usually fights off microbial infections properly, e.g., now, there is no small pox anywhere in the world. A hundred years ago, small pox epidemics were not uncommon. In such an epidemic, people used to be very afraid of coming near someone suffering from disease because they were afraid of catching the disease.PowerPoint Presentation: If you had small pox once, then there is no chance of suffering from it again. Having a disease once was a means to prevent subsequent attacks of the same due to immunity developed. The immune system sees an infectious microbe and responds against it and then remembers it specifically. When next time that particular microbe, its close relative attacks the body, the immune system responds with even greater vigour. It eliminates the reflection more quickly than the first time. It is the basis of the principle of immunization. The immune system develops a memory for a particular infection by putting something, that mimics microbes we want to vaccinate against, into the body. It does not cause disease. It prevents any subsequent exposure to the infecting microbe from turning into actual disease.PowerPoint Presentation: Several vaccines are now available to prevent a whole range of infectious diseases. They also provide a disease-specific means of prevention. There are some vaccines against tetanus, diphtheria, whooping cough, measles, polio etc. The vaccines form the public health programme of childhood immunization to prevent infectious diseases.THE END: THE END You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.