Pathogens Any organism that causes disease in another Most pathogens have to get inside our body to spread infection Once they are inside the body provides ideal living conditions plenty of food water and warmth Standing in their way is our bodys ID: 1003402
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1. Understanding OurselvesPathogens
2. Pathogens Any organism that causes disease in another.Most pathogens have to get inside our body to spread infection. Once they are inside, the body provides ideal living conditions - plenty of food, water and warmth. Standing in their way is our body's immune system - a collective name for the body's co-ordinated response to the invading pathogens.
3. Diseases. BacteriaFungiVirus
4. Bacteria
5. E.Coli (scanning electromicrograph)
6. Contact lens bacteria!
7. Dental plaque bacteria
8. Psoriasis – caused by bacteria
9. Cholera
10. Tetanus
11. Gangrene – caused by bacteria
12. Influenza - flu
13. Measles – caused by a virus.
14. Chickenpox!
15. Bread mold spores
16. Athletes Foot – caused by fungi
17. Thrush – caused by fungi
18. Infected Nails – caused by fungi
19. What ways do we stop pathogens getting in?
20. Vectors
21. What is Malaria?Malaria is a parasitic infection transmitted to humans through the bites of infected female Anopheles mosquitoes. The resulting disease in humans can be devastating. After spreading rapidly through the bloodstream to the liver, the parasite emerges again into the blood stream, finally to settle in the red blood cells, where it multiplies and emerges in bursts of new organisms. These parasites, because of their large numbers, can cause particular damage to the nervous system, liver, and kidney.
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23. Parasite an animal or plant that lives in or on a host (another animal or plant); it obtains nourishment from the host without benefiting or killing the host
24. Host an animal or plant that nourishes and supports a parasite; it does not benefit and is often harmed by the association
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26. Microbes use different means of access to our bodies. One type hitches a ride on or inside another organism, called a vector.
27. For example, malaria gets into humans through the bite of a mosquito. As the mosquito feeds by boring a hole through the skin and sucking blood, the malarial parasite hitches a ride through the mosquito’s saliva into our blood stream.
28. Knowledge of how vectors spread disease helps us to control the infection.
29. Some diseases and disorders are caused by:Vitamin deficiency - scurvy
30. Some diseases and disorders are caused by:Mineral deficiency - anaemia
31. Some diseases and disorders are caused by:Genetic inheritance – red-green colour deficiency
32. Some diseases and disorders are caused by:Body disorders – diabetes
33. Some diseases and disorders are caused by:Body disorders – cancer Cancer cells multiply much more quickly than healthy cells. When this happens, they can stick together to form lumps. These are known as tumours. Cells from tumours can spread to other parts of the body and cause other tumours to grow.
34. Benign tumours: These are not cancers Can often be removed and mostly don't come back Cells from these tumours don't spread to other parts of the body. Malignant tumours: These are cancers Cells in these tumours have gone wrong and start to multiply Can damage other tissue or organs in your body Cells from these tumours can seep into your blood and so spread the cancer These tumours should be removed.
35. There are things you can do to help your body's cells keep healthy throughout your life. Lots of them are about being sensible. Remember: what you do when you are young can affect your health in good and bad ways when you are older.
36. Things you can do:Don't smoke Protect yourself in the sun Eat a healthy diet - plenty of fruit and veg Cut down on red meat Don't drink too much alcohol Keep your body at a healthy weight - not too skinny and not too fat! Exercise Be aware of changes on your body Make sure you check yourself for unusual lumps Get any suspicious lump or mark checked out by a doctor.
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38. Infected. The symptoms of an infectious disease are caused by cell damage or by toxins produced by the pathogens that have got into the body. The invaders can produce chemicals, toxins or enzymes, which the immune system considers as not the body's own. It is not the microorganisms themselves but the protein markers on the cell surface or the chemicals they produce that are recognised as foreign substances. These markers which trigger the immune response are called antigens.
39. Each pathogen has its own antigens, specific antibodies are needed to destroy pathogens with different antigens.
40. Antibodies lock on to antigens causing the death of the pathogens.
41. Human blood sample
42. Immunisation harmless pathogen given - this carries antigens, antigens trigger immune response. by producing antibodies, immunity remains.
43. Immunity to pathogens comes after being infected.
44. Specificity of antibodies
45. The Immune ResponseAntigens: specific proteins on the cell surfaces of microbes (and ‘foreign’ transplanted tissue).Detected by white blood cells (2 types)1. LYMPHOCYTES2. PHAGOCYTESingest and digest microbes to destroy them (can squeeze through walls of blood capillaries produce specific antibodies carried in blood plasmaantibodies ‘lock-on’ to antigensdestroy microbesantibodies prevent infectionproduce specific antitoxins which neutralise poisons themicrobes releasemake microbes stick together (easier for phagocytes to ingest).some cells retain memory to produce the same antibodies quickly, if the same microbe encountered again in the future.
46. How white blood cells work
47. Active immune system Active immunisation is achieved by stimulating the body to produce its own antibodies. Vaccinating people against particular diseases is an example of active immunity
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49. Vaccines contain either:live pathogens treated to make them harmless harmless fragment of the pathogen dead pathogens or the antigen on the pathogen
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51. VaccinationVaccinations are an effective way of stimulating the body’s own defences so that we need not suffer the infectious diseases, such as measles, mumps and whooping cough, that used to be a common feature of childhood.
52. ImmunisationHarmless form of disease organism given.Harmless form still carries antigens – trigger immune response – antibodies madeImmunity remains
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54. Passive immune systemWhen you are given the anti-biotics – you don’t make them yourselves. Antibodies made by another organism can be injected into a person. This is used when there isn't sufficient time for the person to produce their own antibodies, eg in the case of a snakebite. However, the injected antibodies are seen as foreign proteins by the body's immune system, so they are treated as antigens and destroyed fairly quickly. Passive immunisation is therefore only a short-term solution.
55. AntibioticsAntibiotics are substances produced by one type of microorganism that kill or stop the growth of another kind of organism.Antibiotics are used to treat bacterial and fungal diseases.
56. MRSAIt is resistant to most of the commonly used antibiotics. Most of us can carry this bacteria quite naturally in our throats. However, patients in hospitals with weakened immune systems are susceptible to infection . The symptoms are often indicated by redness, and swelling and tenderness at the site of infection.
57. Testing new drugsAnimalsHuman tissueComputer modelsWhat objections could there be to these forms of testing.
58. The use of blind and double blind trials in testing new drugs against placebos.Make a note of these words. Ensure that after viewing these slides that you understand each of them.
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63. Immune System Benefits:Risks:
64. The human immune system defends the body from diseases caused by micro-organisms. Thesepathogens need to be recognised as being harmful to the body1. a What is a pathogen?b Give two examples in your answer.2. What are antigens?3. What are the cells in the human body that are involved in the immune system?4. a What are antibodies?b Why are they specific for just one type of antigen?5. Describe how antibodies destroy pathogens?
65. 1. What is contained in a vaccine?2. Explain why live pathogens are not used in a vaccination.3. How does the body’s immune system respond to the vaccine?4. Explain the difference between the primary response and the memory response.5. a Explain why “memory white blood cells” (lymphocytes) are important.b How long do they last in the body?6. Why does a particular vaccine only give immunity against one disease?7. Put the statements in the table below in the correct order to show what happens when aperson is vaccinated to gain immunity to a disease.
66. Mucus and ciliated cells
67. ILL HEALTH / DISEASEpoor diet, e.g. scurvy, ricketsinherited from parentse.g. cystic fibrosis sickle cell anaemiacells divide / growabnormally / mutation - cancerEffect of lifestylee.g. heart / lung disease & smoking,liver damage & alcoholParts of the body are damaged / worn oute.g. heart disease, diabetes.Infection bye.g. bacteria e.g. tetanus; viruses e.g. measles, AIDS;fungi e.g. athlete’s foot.WHY DO WE GET ILL ?