1. IMMUNITYIMMUNITY ABBOTTS 2010

2. INFECTIONS AND IMMUNITY  TEXTBOOK PAGE 24 2

3. INFECTIONS  Are caused by pathogenic Monera [viruses and bacteria] and Protista [Protozoans] and Fungi  An infection is the detrimental colonization of a host organism by a foreign species. colonizationorganismspecies  Are caused by pathogenic Monera [viruses and bacteria] and Protista [Protozoans] and Fungi  An infection is the detrimental colonization of a host organism by a foreign species. colonizationorganismspecies DEFINITION 3

4. PATHOGENSPATHOGENS  = disease causing micro-organisms bacteria virus fungi, protozoa, 4

5. IMMUNE RESPONSE BY PLANTS  Plant pathogens harm plant growth and reproduction  Plants have an immune system to defend themselves against infections  Plant pathogens harm plant growth and reproduction  Plants have an immune system to defend themselves against infections A plant recognizes the shape of the infecting pathogen and the infected cells are stimulated 5

6. IMMUNE RESPONSE IN PLANTS  Produce salicylic acid  a plant hormone or signal  It is an asprin-like compound  Activate resistance genes which resist the pathogen – eg stop viral replication  Self destruct – form an area of dead cells to prevent the infection from spreading  Produce salicylic acid  a plant hormone or signal  It is an asprin-like compound  Activate resistance genes which resist the pathogen – eg stop viral replication  Self destruct – form an area of dead cells to prevent the infection from spreading 6

7. SYSTEMATIC ACQUIRED RESISTANCE  Salicylic acid moves from the infected site through the phloem to uninfected parts of the plant to activate the immune system to produce defensive compounds to make the entire plant resistant to the pathogen 7

8. TO DO  TEXTBOOK PAGE 24 LEARNING ACTIVITY 15: IMMUNE RESPONSE BY PLANTS  TEXTBOOK PAGE 24 LEARNING ACTIVITY 15: IMMUNE RESPONSE BY PLANTS 8

9. IMMUNE RESPONSE BY ANIMALS  TEXTBOOK PAGE 25 9

10. FIRST LINES OF DEFENCE skin prevents entry tears antibacterial enzymes saliva antibacterial enzymes stomach acid low pH kills harmful microbes mucus linings traps dirt and microbes “good” gut bacteria out compete bad Try to prevent the entry of germs 10

11. PATHOGENSPATHOGENS  = disease causing micro-organisms bacteria virus fungi, protozoa, 11

12. SECOND LINES OF DEFENCE IF GERMS DO GET INTO THE BODY:  Primary response – tries to destroy the germs and prevent them from spreading  Secondary response – if germs do spread, the immune system is activated IF GERMS DO GET INTO THE BODY:  Primary response – tries to destroy the germs and prevent them from spreading  Secondary response – if germs do spread, the immune system is activated 12

13. PRIMARY RESPONSE  Tries to destroy the germs and prevent them from spreading by:  Inflammation (if it is a local infection)  Fever (raised body temperature)  Tries to destroy the germs and prevent them from spreading by:  Inflammation (if it is a local infection)  Fever (raised body temperature) 13

14. INFLAMMATION  Local infection  Inflammation is a process by which the bodies white blood cells protect us from infection and foreign substances such as bacteria and viruses  Local infection  Inflammation is a process by which the bodies white blood cells protect us from infection and foreign substances such as bacteria and viruses 14

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16. SECONDARY RESPONSE/SPECIFIC RESPONSE  TEXTBOOK PAGE 25  If germs do start to spread  Immune system becomes involved  TEXTBOOK PAGE 25  If germs do start to spread  Immune system becomes involved 16

17. IMMUNITY  The body’s active response to an infection 17

18. THE IMMUNE RESPONSE INVOLVES TWO MAIN MEASURES:  Destruction of the invading germs  Holding a memory of this response  Destruction of the invading germs  Holding a memory of this response 18

19. TWO GROUPS OF WHITE BLOOD CELLS INVOLVED IN THE IMMUNE RESPONSE  LYMPHOCYTES  B LYMPHOCYTES  T LYMPHOCYTES  PHAGOCYTES  LYMPHOCYTES  B LYMPHOCYTES  T LYMPHOCYTES  PHAGOCYTES They are part of a huge army in our bodies There are about one trillion B lymphocytes And one trillion T lymphocytes They are found in the tonsils, lymph glands, spleen and blood They are part of a huge army in our bodies There are about one trillion B lymphocytes And one trillion T lymphocytes They are found in the tonsils, lymph glands, spleen and blood 19

20. ANTIGENS ANTIGENS  all cells have surface markers called antigens.  body can recognise these as self or non-self (foreign) 20

21. B LYMPHOCYTES  Also called antibody cells  If a germ gets into the body, it is detected by these cells 21

22. HOW B LYMPHOCYTES DESTROY GERMS  Germs have molecules called antigens on their surface  The antigen tells the B lymphocyte that the germ is ‘non-human’ and dangerous  There are countless types of B lymphocytes  Each is able to recognize its own specific antigen  The B lymphocyte replicates rapidly producing lots of identical cells (clones)  These newly formed B lymphocytes produce proteins called antibodies into the blood plasma  Germs have molecules called antigens on their surface  The antigen tells the B lymphocyte that the germ is ‘non-human’ and dangerous  There are countless types of B lymphocytes  Each is able to recognize its own specific antigen  The B lymphocyte replicates rapidly producing lots of identical cells (clones)  These newly formed B lymphocytes produce proteins called antibodies into the blood plasma 22

23.  The antibodies combine with the antigens on the surface of the germ  DIAGRAM PAGE 25 – BINDING OF ANTIBODIES AND ANTIGENS  This will destroy or neutralise the germ  Some of the B lymphocytes stay in the lymph glands as memory cells  If they encounter the antigen again, they mount a response very quickly and kill the germ before it can breed  This is the basis of immunity 23

24. HOW ANTIBODIES DESTROY GERMS  DIAGRAM: TEXTBOOK PAGE 25 METHODS OF GERM DESTRUCTION BY ANTIBODIES  Antibodies could:  Cause bacterial cells to burst  Label germs for phagocytosis  Cause germs to clump together [clumps are easier to ingest by phagocytosis]  Neutralize bacterial toxins  DIAGRAM: TEXTBOOK PAGE 25 METHODS OF GERM DESTRUCTION BY ANTIBODIES  Antibodies could:  Cause bacterial cells to burst  Label germs for phagocytosis  Cause germs to clump together [clumps are easier to ingest by phagocytosis]  Neutralize bacterial toxins 24

25. T LYMPHOCYTES  There are different types of T lymphocytes  Each cell has a unique role to play in the immune response  CD4 Cells [helper T cells]  Killer T cells PAGE 26 CD4 cells are a type of white blood cell (lymphocyte Killer T cells 25

26. CD4 CELLS/ HELPER T CELLS  Begin the immune response to infections  Without these cells the other cells will not do anything  Body’s ability to fight infections would be very poor  Begin the immune response to infections  Without these cells the other cells will not do anything  Body’s ability to fight infections would be very poor Page 26 26

27. KILLER T CELLS/ CYTOTOXIC T CELLS  They attack and destroy:  Cancer cells  Cells infected with viruses and some parasites  Transplanted organs [unless immunosuppressive drugs are given to the patient]  They attack and destroy:  Cancer cells  Cells infected with viruses and some parasites  Transplanted organs [unless immunosuppressive drugs are given to the patient] 27

28. TO DO  TEXTBOOK PAGE 26 LEARNING ACTIVITY 17 T LYMPHOCYTES AND IMMUNE RESPONSE  TEXTBOOK PAGE 26 LEARNING ACTIVITY 17 T LYMPHOCYTES AND IMMUNE RESPONSE 28

29. PHAGOCYTES (CELLS THAT EAT!)  DIAGRAM TEXTBOOK PAGE 26  Are large lymphocytes (white blood corpuscles)  Can change shape  They engulf germs by phagocytosis [and also dead cells and foreign particles]  DIAGRAM TEXTBOOK PAGE 26  Are large lymphocytes (white blood corpuscles)  Can change shape  They engulf germs by phagocytosis [and also dead cells and foreign particles] 29

30. HOW DO PHAGOCYTES DESTROY GERMS  Move around the body looking for germs  Squeeze through gaps in capillary walls and reach any part of the body  When it comes into contact with a germ, it engulfs it and takes the germ into the cell  Germ is digested and killed  Process called phagocytosis  Move around the body looking for germs  Squeeze through gaps in capillary walls and reach any part of the body  When it comes into contact with a germ, it engulfs it and takes the germ into the cell  Germ is digested and killed  Process called phagocytosis PAGE 26 30

31.  Phagocytosis of E coli 31

32. TO DO  TEXTBOOK PAGE 27 LEARNING ACTIVITY 18: DEALING WITH INFECTIONS  TEXTBOOK PAGE 27 LEARNING ACTIVITY 18: DEALING WITH INFECTIONS 32

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