THE BODY'S DEFENSES. The Immune System

Transcription

1 THE BODY'S DEFENSES The Immune System

2 MAIN POINT #1 The body is first protected by a barrier

3 THE OUTERMOST BARRIERS Sighty acidic, dry skin Prevents iving things from growing on us The Integumentary System

4 SKIN SECRETIONS Make skin acidic Saiva, tears and mucous a wash away most harmfu bacteria Secretions contain antibacteria proteins such as ysozyme

5 MUCUS Traps microbes and partices Swaowed and acid from the stomach kis bacteria We aso expe mucus through sneezing and runny noses (rhinorreah)

6 MAIN POINT #2 We have a non-specific immune system that attacks any invading pathogen

7 NON-SPECIFIC RESPONSES The body has white bood ces that attack any foreign invaders

8 NEUTROPHILS WBCs attracted to damaged ces Enguf and destroy microbes via phagocytosis 60-70% of a WBCs Short ife-span

9 MONOCYTES More effective phagocytes Form macrophages Attach to bacteria surfaces and digest bacteria with ysosomes Ony about 5% of WBCs

10 EOSINOPHILS Fight off arger invaders Shoot enzymes at arge parasites such as bood fukes

11 NATURAL KILLER Destroy virusinfected body ces Burst the membrane of a ce, destroying it Protects against vira takeovers and tumors

12 INFLAMMATORY RESPONSE Cuts or bacteria infections cause the reease of histamines by basophi and mast ces This causes bood to fow to capiaries to cuts and infections

13 INFLAMMATION CON. Increased bood fow brings cotting factors as we as WBCs to attack the invader Fuid and WBCs eak out of capiaries, which is why injured areas swe

14 MAIN POINT #3 The third ine of defense is specific reactions to disruption of homeostasis

15 LYMPHOCYTES WBCs that circuate in bood and ymph 2 types - T Ces - B Ces Recognize foreign invaders

16 B CELLS Foreign moecues caed antigens are recognized by B Ce's receptors B ces reease antibodies which identify and attack specific foreign invaders

17 T CELLS Simiar to B ces but do not secrete antibodies Identify and attack invaders It is T ces that are attacked by the AIDS virus

18 QUICK NOTE Antigen = foreign moecue Pathogen = foreign organism Often used interchangeaby WBCs may recognize an antigen that is a part of a pathogen

19 ONCE AN ANTIGEN BINDS... Lymphocytes divide into 2 sets of ces Effector ces which fight the infection Memory ces which are ongived and remember the antigen

20 QUICK REVIEW We have miions of ymphocytes When a singe ymphocyte recognizes an antigen, it mutipies to attack the invader and remember it Creates a specific response

21 PRIMARY VS. SECONDARY IMMUNE RESPONSE It takes about days to generate the maximum response to a foreign microbe and cear the antigens from the body During the wait time is when peope fee i If exposed to the same antigen, it takes ony 2-7 days to cear the body, which is caed the Secondary Immune Response - More antibodies that are more specific are made due to memory ces - This is caed immunoogica memory

22 SELF-TOLERANCE When ymphocytes are being made they are tested with moecues from the body Any T or B ce that reacts to the body is destroyed This, however, goes wrong in diseases ike mutipe scerosis

23 MAIN POINT #4 Specific immune responses consist of antibodies and T ces fighting off foreign antigens

24 IMMUNE RESPONSES The humora response defends against extraceuar antigens (in the bood) The cemediated response defends against pathogens inside of ces Formation of antibodies in bood Destruction of infected or cancerous ces

25 HELPER T CELLS Hep stimuate both responses Important in recognizing antigens a second time It is these specific T ces that HIV and AIDS affect

26 CELL-MEDIATED RESPONSE Antigens bind to a T ce caed a cytotoxic T ce It creates memory ces and active cytotoxic T ces Active Cytotoxic T ces yse and burst infected and cancerous ces

27 HUMORAL IMMUNITY OVERVIEW Antigens are recognized by B ces B ces give rise to pasma ces and memory B ces Pasma ces secrete antibodies Antibodies bind antigens and hep the eiminate them

28 MAIN POINT #5 Antibodies hep fight viruses and bacteria outside of the ces in a number of different ways

29 ANTIBODIES Proteins that can bind mutipe antigens Heps disposa of pathogens in a number of ways

30 NEUTRALIZATION Antibody binds and bocks activity of antigen i.e. an antibody can bind to the part of a virus that inserts the virus into ces

31 OPSONIZATION Antibodies bind and make it easier for macrophages to digest pathogen

32 AGGLUTINATION Antibodies can cump bacteria or viruses together Antibodies have mutipe attachment sites Makes it easier for phagocytes to digest

33 1. Barriers Skin/mucus/ysozyme 2. Infammatory Response Basophis reease histamine Sweing, non-specific WBCs REVIEW Neutrophis, Monocytes (macrophages), eosinophis, natura kier ces 3. Immune Response Lymphocytes attack specific antigens Humora (B ces, antibodies) and Ce-mediated (T ces)

34 WHITE BLOOD CELLS (LEUKOCYTES) Neutrophi most common, phagocyte Monocyte forms macrophage Eosinophis Attacks arger parasites Basophis Reease histamine Lymphocyte Recognition and attack of specific pathogens

35 MAJOR HISTOCOMPATIBILITY COMPLEX (MHC) Moecues on ce surface that hep the body distinguish sef from non-sef Ces can dispay sef MHC moecues to avoid being attacked But a cancerous ce or a WBC that has ingested a foreign moecue can dispay a non-sef moecue, so that it is attacked

36 THE IMMUNE SYSTEM MAKES TISSUE TRANSPLANT DIFFICULT It is difficut (but possibe) to transfer tissues such as bood, skin or organs to new individuas The body recognizes foreign tissues Easier to use tissue from one's own body

37 TISSUE TRANSPLANTS The MHC recognizes foreign tissues Donors and recipients must be cosey matched Twins and sibings are usuay the cosest matches

38 BLOOD TRANSFUSIONS Bood types can be considered antigens Type A produces A antigens, B produces B antigens, O produces no antigens Peope with B or O bood types produces A antibodies Peope with O bood produce both antibodies (can't receive A or B bood)

39 BLOOD TRANSFUSIONS GONE WRONG You cannot receive bood for which you have antibodies! If you re type O, you produce A and B antibodies you can ony receive type O bood If you re AB you produce no antibodies you can accept any bood (this oversimpifies things a bit, there is aso the Rh factor and other bood antigens)

40 ALLERGIES Aergens act as antigens, causing mast ces to overreease histamine Causes bood to fow to capiaries

41 ANAPHYLACTIC SHOCK When too much histamine is reeased bood pressure drops Too much bood fows out of the capiaries Epinephrine must be taken to counteract this effect

42 MULTIPLE SCLEROSIS The immune system breaks down nervous tissue Usuay gets worse and worse Not deady, but debiitating No cure