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Word Roots an- = without; -aphy = suck (anaphylactic shock: an acute, life-threatening, allergic response) anti- = against; -gen = produce (antigen: a.

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Presentation on theme: "Word Roots an- = without; -aphy = suck (anaphylactic shock: an acute, life-threatening, allergic response) anti- = against; -gen = produce (antigen: a."— Presentation transcript:

1 Word Roots an- = without; -aphy = suck (anaphylactic shock: an acute, life-threatening, allergic response) anti- = against; -gen = produce (antigen: a foreign macromolecule that does not belong to the host organism and that elicits an immune response) macro- = large; -phage = eat (macrophage: an amoeboid cell that moves through tissue fibers, engulfing bacteria and dead cells by phagocytosis) mono- = one (monocyte: an agranular leukocyte that is able to migrate into tissues and transform into a macrophage) neutro- = neutral; -phil = loving (neutrophil: the most abundant type of leukocyte; neutrophils tend to self-destruct as they destroy foreign invaders, limiting their life span to but a few days) perfora- = bore through (perforin: a protein that forms pores in a target cells membrane) 1/22/2014 1

2 2 Immunity: body's ability to destroy pathogens or other foreign material and to prevent further cases of certain infectious diseases Go on to the Campbell Biology site, Chapter 24 activities, do them as we learn the work, and then take the activity quiz and submit it to me when we are done with the chapter.

3 24.1 Nonspecific defenses against infection include the skin and mucous membranes, phagocytic cells, and antimicrobial proteins Read pp /22/20143

4 Pathogen just waiting to enter body to produce disease Disease: change interfering w/normal body functioning Symptoms: changes produce in body Pathogens (disease- causing microorgan- isms: viruses, bacteria, fungi, protists) cause infectious diseases Infection: body invaded by pathogen Indirect contact with infected person Airborne-coughing, sneezing common cold, measles, mumps, influenza Direct contact with infected person Sexual contact Through contaminated food or water Food poisoning, handled by infected person Through bite of infected animal-vector Ticks, mosquitoes 1/22/20144

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7 Vocabulary Toxins: poisonous substances produced by microorganisms Transported by blood Cause serious and fatal effects Endemic: disease restricted to particular region (cholera/plague in parts of Asia) Epidemic Disease involving many more people than usual in particular community, or One that spreads into regions where it does not normally occur (influenza, SARS, AIDS) Pandemic: epidemic spreads throughout world 1/22/20147

8 8 do not distinguish individual infectious agents-guards against all infections, regardless of cause recognizes specific invaders/attacks/eliminates them First line of defense (cant cause disease if kept out) (gets through skin/mucus/etc.)

9 1st line of defense keep things out that cause diseases Skin : Tough, physical, unbroken barrier that blocks pathogens from entering body Glandular secretions (sweat, saliva, tears) give chemical defenses (acidic pH, lysozyme) that inhibit or kill microbes Mucus membranes Mucus traps microbes Cilia Filters air Mucous propelled to throat, then swallowed Stomach HCl/digestive enzymes Kill swallowed bacteria 1/22/2014 9

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12 2 nd line of defense WBCs leave blood to find invading cells in interstitial fluid/body tissues Phagocytes Engulf microbes Neutrophils/Monocytes Phagocytize bacteria/viruses Macrophages Develop from monocytes Phagocytize bacteria/viruses Natural killer cells Attack cancer cells/virus-infected cells Cause cytolysis 1/22/201412

13 Antimicrobial protein produced by virus- infected cells Cant save invaded cells Helps healthy cells resist viruses Interferes with viral replication Slows down progress of infection Give specific defenses time to respond 1/22/ Interferon

14 Complement proteins Inactive antimicrobial proteins circulate in blood Activated by immune system or by microbes Action 1.Coat microbe surfaces/easier for macrophages to engulf 2.Cut lethal holes in microbial membranes 3.Amplify inflammatory response 1/22/201414

15 24.2 The inflammatory response mobilizes nonspecific defense forces (2 nd line of defense) Read pg /22/201415

16 1/22/ Swelling against nerves causes pain Accumulation of fluid dilutes toxins present Histamine causes sneezing, coughing, redness, itching, runny eyes/nose Vasodilation: area becomes hot, red, swollen due to increased blood supply

17 Systemic action of response, due to microbes or their toxins circulating in blood Produces more WBCs Cause fever 1.Stimulate phagocytosis/inhibit microbe growth 2.Chemicals released stimulate WBC actions 3.Microbes survive within narrow temperature range Can often slow down/stop growth of some >39 o C/103 o -dangerous >41 o C/105 o -often fatal 1/22/201417

18 24.3 The lymphatic system becomes a crucial battleground during infection 24.4 The immune response counters specific invaders 24.5 Lymphocytes mount a dual defense 24.6 Antigens have specific regions where antibodies bind to them Read pp /22/201418

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20 Lymphatic system Open network of vessels, lymph nodes, associated glands Functions Return excess fluid from interstitial fluid to circulatory system Fight infection 1/22/ Filters pathogens from blood Contain WBCs that respond to trapped pathogens

21 Lymph fluid of lymphatic system Lymph nodes Activated during infection (swell, tender, aches, pain) Lymph Enters through open, lymphatic capillaries Largest lymph ducts empty into circulatory system veins in shoulders Similar to interstitial fluid (less oxygen, fewer nutrients) Microbes from infected sites/cancer cells phagocytized by macrophages Lymphocytes activated/mount specific immune response 1/22/201421

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23 Specific defenses Immune system (immunity) 3rd line of defense Extreme specificity, memory, response on 2 nd exposure Amplifies inflammatory & complement responses Self vs. nonself Antigen Any molecule (polysaccharide/protein) eliciting immune response Pathogen or part, mold, bacterial toxin, insect venom, pollen, viruses Produce antibodies Attaches to antigen Antigen remembered and reacted to in future 1/22/201423

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25 1/22/ Lasts as long as they remain in circulation, usually for several weeks Immunity: resistance to specific invaders growth of B and T cells in response to infection long lasting

26 Lymphocytes (WBCs in immune system arise from stem cells in bone marrow/accumulate in lymph/lymph nodes/spleen/blood) Humoral immunity Fight bacteria/ viruses in blood/ interstitial fluid Mounted by B cells that produce antibodies Transferred passively Cell-mediated immunity Fight bacteria/ viruses/ fungi/ protozoan/cancer inside cells Mounted by T cells that kill directly Not transferred passively 1/22/201426

27 1/22/ B/T cells must mature Recognize/respond to specific antigen Cells have antigen receptors that bind antigens Humans have 100 million to 100 billion different kinds of B/T cells

28 24.7 Clonal selection musters defensive forces against specific antigens 24.8 The initial immune response results in a type of memory Read pp /22/201428

29 1/22/ Plasma cells secrete up to 2000 antibody molecules/sec. during 4-5 day lifetime Enter bloodstream, combines w/antigens & clump Macrophages engulf & destroy clumped antigens

30 Immune response 1 o immune response Effector cells produced Delay between exposure to antigen and secretion of antibodies Release of modest levels of antibodies 2 o immune response Exposed to same antigen Faster response Lasts longer Higher antibody levels 1/22/201430

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32 24.9 B cells are the main warriors of humoral immunity Antibodies are the weapons of humoral immunity Antibodies mark antigens for elimination Monoclonal antibodies are powerful tools in the lab and clinic Read pp /22/201432

33 B cells produce Antibodies Protein in blood plasma Attaches to one kind of antigen Antigen-binding (determinant) site is antigen specific May have several antigenic determinants 5 major classes of human antibodies based on nature of C region (immunoglobulins-IgG, IgA, IgD, IgE, IgM) 1/22/

34 1/22/ All mechanisms involve specific recognition phase (antibodies of humoral immunity) followed by nonspecific destruction phase (phagocytosis/complement proteins)

35 Monoclonal antibodies Medical diagnoses (pregnancy tests- test for presence of specific hormone, HCG) Target drugs to cells that cause disease (cancer) 1/22/201435

36 24.13 T cells mount the cell- mediated defense and aid humoral immunity Cytotoxic T cells may help prevent cancer The immune system depends on our molecular fingerprints Read pp Activity 24A (1 st of 2) 1/22/201436

37 T cells immune response Circulate in blood/lymph Attack infected body cells Promote phagocytosis by other WBCs Stimulate humoral response (B cells produce antibodies) Rejection by T cells 1/22/

38 1/22/ Helper T-cells recognize self protein/foreign antigen presented by APC 2.T cells activated by binding to self- nonself complex

39 1/22/ Helper T cells : Activate cytotoxic T cells and macrophages Stimulate release of antibodies by B cells Interact w/ antigen-presenting cells (APCs) getting macrophages involved

40 1/22/ apoptosis (programmed cell death) and lysis (cancer)

41 1/22/ Antigens are proteins specific to each particular microorganism. They act as identity card that allows immune system to recognize invader organisms.

42 1/22/ Activated B-cell produce millions of antibodies, a protein that binds with antigen. Eventually, # infectious agents decreases. Need to inactivate cells and put them to rest, or theyd continue to fight own cells. T-suppressor cell (or T8) sends out messages to other cells and "de- activate" them.

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44 Recognition of self over nonself Proteins on cell surface specific to each person Lymphocytes recognize Class I proteins on all nucleated body cells Class II proteins found only on B cells, activated T cells, macrophages Determined by 6 loci, each w/100s alleles Only identical twins can have identical set of self proteins Coded for by MHC (major histocompatibility complex) genes 1/22/201444

45 Transplant problems Different self proteins recognized as foreign Caused by T cell immune response Risk of rejection minimized by Donors self proteins match recipients as closely as possible Immune suppression drugs Interfere with immune system Cyclosporine suppresses only cell- mediated response 1/22/201445

46 24.16 Malfunction or failure of the immune system causes diseases Allergies are overreactions to certain environmental antigens AIDS leaves the body defenseless Read pp Activity 24B (last one) 1/22/201446

47 Immune disorders overreaction to antigens Physical/emotional stress weakens immune system Autoimmune diseases: immune system turns against bodys own molecules Rheumatoid arthritis: antibody-mediated damage to joints, bones, and cartilage Multiple sclerosis: T cells attack myelin Crohns: attacks digestive system Insulin-dependent diabetes: insulin-producing cells are subjected to cell-mediated response Lupus: production of antibodies against molecules such as histones and DNA 1/22/201447

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49 1/22/ nd exposure Histamine in greater amounts Allergy symptoms (nasal irritation, itchiness, tears ) 1 st exposure (pollen/dust/insect toxins/cat saliva/ proteins) 1.Mast cells found thruout body/especially in nasal lining 2.Histamines increase flow of blood/fluids, (sneezing, runny eyes/nose) Allergies: overreactions to environment allergens Antihistamines interfere w/histamine action and give temporary relief

50 1/22/ Asthma Serious allergic reactions Smooth muscles contract around bronchioles Anaphylactic shock Mast cells release large amount of histamine (inflammatory)/dilates blood vessels suddenly Sudden drop in blood pressure (shock) Potentially fatal Extreme allergy to certain allergens

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52 Immunodeficiency diseases Lack component(s) of immune system Susceptible to infections that would ordinarily not cause problem (opportunistic infection) SCID (severe combined immunodeficiency)- inherited disorder, T/B cells absent or inactive Hodgkins disease: cancer of lymphocytes; treatment can suppress immune system HIV leads to AIDS Attacks helper T cells Eliminates humoral/cell-mediated immunity 1/22/201452

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