Immune system-midterm 1 – Flashcards
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Name some immune system functions?
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● Protection from: pathogens, foreign molecules (toxins) ● Removes dead or damaged cells (inflammation response) ● Recognize & remove abnormal cells (cancers)
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Describe characteristics of bacteria?
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● Cells surrounded by a cell wall ● Survive & reproduce outside a host ● Killed/inhibited by antibiotics
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Describe characteristics of viruses?
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● Nucleic acid core with protein coat ● Parasitic and need a host to reproduce ● Can't be killed by antibiotics ● Can be inhibited with anti-viral meds
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What is an incorrect immune response?
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● Autoimmune - type I diabetes ● Attack against self
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What is an overactive immune response?
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● Allergies
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What is an lack of immune response?
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● Immunodeficiency response- AIDS
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What are the lymphoid tissues purpose?
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● Produce/store/process lymphocytes
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Examples of lymphoid tissues?
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● Bone marrow ● Lymph nodes ● Spleen ⇒ stores WBC ● Thymus ⇒ thymosine develops immune system ● Tonsils/Adenoids Appendix ● Peyer's Patches (GAIT) ⇒ gut
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The Lymphatic System functions?
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● Drains tissue ● Filtering system ⇒ lymph nodes & protects against pathogens ● Fat transport
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What are Lymph Nodes functions?
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● Remove impurities & pathogens from lymph ● Lymphocyte storage ● Phagocytosis ● Macrophages- Sinusoids ● Own blood supply to drain - low pressure
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What is Basophils & Mast Cells functions? ****
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● Granulocytes ● Inflammation ● Allergic response
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What is Neutrophils functions? ****
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● Granulocytes ● Phagocytes ● 50 - 70% in blood ● Immature called "bands" or "stabs" ● Ingest and destroy invaders
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What is Eosinophils functions? *****
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● Granulocytes ● Phagocytes ● Cytotoxic Cells ● 1 - 3% in blood ● Destroy invaders, particularly antibody-coated parasites
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What is Monocytes & Macrophages functions? ****
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● Phagocytes ● Antigen-presenting cells ● 1 - 6% in blood ● Mononuculear phagocyte system ● Ingest and destroy invaders ● Antigen Presentation
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What is Lymphocytes & Plasma Cells functions? ****
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● Cytotoxic Cells ● Antigen-presenting cells ● 20 - 35% in blood ● B Lymphocytes ↳ Plasma Cell/Memory Cells ● T Lymphocytes ↳ Cytotoxic T-cells/Helper T cells ● Natural Killer Cells ● Specific responses to invaders & antibody production
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What is Dendritic Cells functions? ****
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● Antigen-presenting cells ● Langerhans Cells/Veiled cells ● Recognize pathogens & activate other immune cells by antigen presentation
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Four Steps in an Immune Response?
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1. Detect & identify foreign substance 2. Communication with other immune cells 3. Coordinate response 4. Destroy or suppress the invader
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What are the Non-Specific/Innate Immune Response? ***
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● Quick ● External defences ● Inflammation ● Humoral: Complement system & cytokines; interferon ● Cellular: Macrophages, Granulocyte; Basophils/eosinophils/neutrophils & NK cells
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What are the Specific/Acquired Immune Response? ****
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● Slower but stronger ● Reacts to/targets ANTIGEN ● T-Cells ● B-Cells ● Lymphocytes/Plasma Cells ● Humoral: Antibodies/B-cells ● Cellular: Lymphocytes/dendritic cells
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What are some External Defences for physical barriers? ***
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● Skin- Biggie ● Mucous Membranes
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What are some External Defences for Chemical Barriers? ****
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● Stomach acid ● Lysozyme in many secreted fluids ● Acid -> stomach, vagina & mouth ● Mucous -> Vagina, mouth, nose, eyes ● Cough/sneeze reflex ● Hair/cilia -> respiratory tract
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What are the Steps in inflammation? ***
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1. Tissue injury releases chemical signals- histamine 2. Vasodilation & increase permeability of blood vessel; migration of WBC's; phagocytes/neutrophils; RBC's; heat/proteins/water - swelling/pus to injury 3. Platelets/clotting factors form a wall/ridge around site to limit infection
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Purpose of inflammation? ***
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● Attract immune cells & chemical mediators to sites of infection ● Create physical barriers to prevent infections from spreading ● Promote tissue repair
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Purpose of cytokines & histamine in inflammatory response? ***
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● Cytokines from injury/infected site; causes mast cells to release histamine ↳ Cytokines mediate inflammatory response ● Histamine Causes; ↳ increased: blood flow to site; red/hot, permeability of capillaries, WBC's/proteins to site & fluid; swelling/edema
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Purpose Interleukins as inflammatory chemical? ***
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● Subset of cytokines ● Cause fever ● Change permeability of vessels to WBC's, proteins & clot factors
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Bradykinin as inflammatory chemical? ***
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● Pain receptors & swelling
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Complement Proteins as inflammatory chemical functions? ***
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● Cascade produces a Membrane Attack Complex (MAC) ● Imbed into damaged cells marked by antibodies & creates pores and lysis the cell by allowing water & ions into the cell ● Free circulating in blood
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What is Phagocytes functions? ****
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● Ingest foreign cells & chemicals ● Non-specfic ● Macrophages/monocytes ● Neutrophils ● Natural Killer (NK) cells ● Can trigger inflammation & chemical responses ● Activate clotting/anti-clotting pathways ● Hormonal body regulation to infection
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What is Natural Killer (NK) Cells functions? *****
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● Kill tumour cells & infected cells ● Macrophages ● Genetics determines how many
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How does Phagocytosis of Pathogens with polysaccharide capsule happen? ****
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● harder to capture- no membrane receptor on pathogen ● Antibodies bind to pathogen then engulfs
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How does Phagocytosis of Pathogens without capsule happen? ****
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● Membrane receptors bind to pathogen and engulfs
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Phagocytosis kill pathogen/antigen via? ****
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● Lysosomal Enzymes ● Lysosome ↳ Enzymes & oxidants ● Phagosome ↳ Ingested pathogen
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What are the Phagocytes; Neutrophils functions? ***
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● Mobile & quick eaters
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What are the Macrophages functions? ***
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● Less mobile & big eaters
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What are the Antigen-Presenting Cells function? ***
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● Marks a cell for helper T-cells ● Mediate an increased response
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What are the NK Cells function? ****
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● Induce apoptosis of infected cells/antibody-coated cells ● Some attack tumour cells ● Secrete chemical signals ● Interferon-gamma: activate macrophages & other immune cells; T-cells
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What are the Interferon function? ***
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● Innate Immunity ● Released by infected cells ● Prevent infection of healthy cells by host cell 2 ● Host cell 2 turns on antiviral proteins to block viral replication
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What are the Complement Proteins? ****
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● Can trigger or enhance: ↳ Inflammation ↳ Chemotaxis ↳ Opsonization; phagocyte activation; antigen/antibody apoptosis ↳ MAC pore ↳ Vasodilation for inflammation
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What is Active Natural Immunity?
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● Immune response
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What is Active Acquired Immunity?
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● Vaccinations
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What is Passive Natural Immunity?
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● Breast milk
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What is Passive Acquired immunity?
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● Gamma globulins/allergy shots
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What is Lymphocyte Clones?
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Specific immunoglobulins on the surface that bind a specific antigen Usually B-cells
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Steps in an Immune response?
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1°- Naive lymphocyte that has not yet been stimulated → Antigen binds to specific lymphocyte clone → Clonal expansion where cells multiply rapidly and become Plasma cells, helper, cytotoxic and suppressor T-cells 2° Other cells become memory B-cells and provide a stronger faster response to 2nd exposure
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What is B-Cells in specific immunity fucntions?
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Attack free virus in the blood Antibody reaction Mature in the bone marrow Humoral immunity
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What is T-Cells in specific immunity functions?
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Attack infected cells Defend against intracellular pathogens Mature in the thymus Cell-mediated immunity
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What is B- Lymphocytes functions?
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Humoral Immunity B-cells bind to antigen and become activated Clonal expansion Plasma Cells → Secrete antibodies Memory cells → clones; faster 2° response
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What is T lymphocytes pathway?
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Helper T-Cells → Secrete cytokines; Increase B-cells and T-Cells response and fever Cytotoxic/killer T-Cells → directly attack infected cells; phagocytes Supressor T-Cells limit the +ve feedback from the Helper T-Cells
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3 Types of Lymphocytes?
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B- Lymphocytes T-Lymphocytes NK cells
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Binding if antibodies to antigens inactivates them by?
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Neutralization;blocks viral binding site; coats bacteria, Agglutination of microbes, precipiation of dissolved antigen → enhances phagocytosis Activation of Complement System → cell lysis
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5 Classes of antibodies/immunoglobulins/gamma globulins?
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IgG IgA IgE IgM IgD
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Role of IgG? ****
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Most common 2° response
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Role of IgA? ****
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In saliva, tears, breast mile etc.
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Role of IgE? ****
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Involved in allergic response
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Role of IgM? ***
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Involved in 1° response
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Role of IgD? ****
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On surface of B-cells; role is unclear
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Functions of Antibodies for B-Lymphocytes?
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Activate B-Lymphocytes → clonal expansion to memory cells and plasma cells → Secrete antibodies
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Functions of Antibodies for Opsonins?
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Activate Complement system or mast cells → Enhance phagocytosis
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Functions of Antibodies for Bacterial Toxins?
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Antigen clumping and inactivates it → enhanced phagocytosis
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Functions of Antibodies for NK cell or eosinophil?
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Activates antibody-dependent cellular activity
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Functions of Antibodies for Mast Cells?
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Triggers degranulation
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Functions of Antibodies for Complement System?
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Activates complement system → triggers mast cell degranulation
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What is T-Cell Receptors functions?
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Recognize foreign antigens only with Major Histocompatibility Complex (MHC) proteins
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What is MHC Proteins function?
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Found on all body cells except RBCs Vary from 1 person to another- Specific
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What is Activation of T-Lymphocytes?
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MHC antigenComplex binds to T-cell Receptor → Signal transduction
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What is MHC Class I Proteins? *****
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On all infected nucleated cells of the body Recognized by cytotoxic T-Cells
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What is MHC Class II Proteins? ****
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Only on antigen-presenting cells Recognized by Helper T-Cells → Activate other immune cells
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What is Cytotoxic T-Cells function?
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Attack infected cells with MHC class I proteins→ Release Perforin by exocytosis → expose to Ca ²⁺ perforin spherical to cylindrical shape and inserts into cell membrane → Stimulate apoptosis; cell suicide via creating pores in target cell
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What is Functional roles of Helper T-Cells?
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Need MHC Class II proteins first Secrete cytokines → Fever and increase number of B-cells and T-Cells Bind to B-Cells to differentiate into plasma cells/ clone cells
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How a Helper T-Cell binds?
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MHC II is an antigen-presenting cell with self-nonself complexes → binds & stimulates Helper T-Cell with Interleukin-1 → Interleukin-2 stimulates cell division → B-Cell; humoral immunity/antibodies & cytotoxic T-cell; cell mediated immunity
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What are some factors that affect resistance to infection?
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Malnutrition- ↓ proteins Pre-existing disease Tissue Injury Stress State of mind Genetic Disorders Hormone Changes Previous exposure
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What is Hypersensitivity? ***
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Over-reaction of immunity
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What is Autoimmune?***
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Immunity against self
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What is Isoimmune? ***
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Immunity against other humans
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What is Immunodeficient? ***
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Immunity lacking
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What is the allergic/inflammatory response to a nonpathogenic antigen/antigen?
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Exposure → Overproduce IgE → Affinity for basophils & mast cells → Rupture mast cells → Release histamine, serotonin & bradykinin → Local edema, swelling, congestion & hives
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What is Immediate Hypersensitivity? ****
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Occurs within minutes Mediated by antibodies
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What is Delayed Hypersensitivity? ****
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Occurs after hours to days Mediated by Helper T-Cells and Macrophages that stimulate IgE → Mast Cells → Cytokines, histamine etc. → Vasodilation, bronchoconstriction & inflammation
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What is Type I Hypersensitivity? ***
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Excess IgE bound to mast cells → Inflammation Allergies
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What is Type II Hypersensitivity? **
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IgM or IgG cause destruction of foreign cells Cell lysis Blood incompatibility
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What is Type III Hypersensitivity? **
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Immune complexes are deposited in tissue & vessels Inflammation & tissue destruction Immune complexes- glomerulonephritis
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What is Type IV Hypersensitivity?***
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Sensitized T lymphocytes release cytokines Inflammation & tissue damage Delayed- poison ivy, & organ rejection
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What is Hay Fever? ***
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Delayed Hypersensitivity Mast cell response ↑ Eosinophils & BAsophils Redness, heat, swelling & itching Runny nose, coughing, sneezing, wheezing & nasal congestion
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What is Food/Animal Allergies? ***
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Immediate Hypersensitivity Cramping, Diarrhea, vomiting, Hives, rashes & runny eyes & nose
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What is Allergy Shots? **
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Antigen administered in increased doses → ↑ production of IgG IgG binds to the allergen before it can bind IgE → ↓ allergy response
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What is Anaphylaxis? **
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Severe hypersensitivity Mast cells bound to IgE → Histamine → Blood vessels dilate & leak plasma → BP (blood pressure) falls & airway smooth muscle constricts → ↓venous return → ↓ CO (cardiac output), Shock/hypotension, respiratory distress
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Anaphylaxis Causes, Symptoms & Treatment? **
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Causes: Antibiotics, Foods, Latex, Vaccines etc. Symptoms: Itchy throat & tongue, swollen face & throat Treat: Epinephrine (Epi), Corticosteroids/cortisol & Antihistamines
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What is Blood Transfusion Reaction for Isoimmune disorder? ***
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Symptoms: chills/shivering, fever & hemolytic anemia Cause: Other RBC antigens recognized by MHC proteins as foreign
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What is A & B Antigens?
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Naturally Occuring
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What is Rh Antigens?
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Acquired need previous exposure
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Who is the universal blood donor and why?
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Type O because they have no A or B antigens
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Who is the universal blood recipient?
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Type AB because they have A & B Antigens
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Erythroblastosis Fetalis as an Isoimmune Disorder? ***
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Mother's antibodies attack & destroy antigen on babies RBC → death Only affects 2nd Rh ⁺ve babies carried by an Rh ⁻ve mother
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Erythroblastosis Fetalis as an Isoimmune Disorder Treatment? **
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Transfuse baby's blood with RhoGAM gamma globulins that binds Rh⁺ve cells so mum doesn't make antibodies Done in utero and after birth
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What is Autograft Organ Transplant?
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From Oneself Skin graft
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What is Isograft Organ Transplant?
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From a twin
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What is Xenograft Organ Transplant?
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From an animal
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What is Allograft Organ Transplant?
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From another person that matches MHC proteins
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How to prevent organ rejection? **
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Immunosuppressants eg. cyclosporin
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What is Autoimmune Diseases? ***
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Immune doesn't normally react to "self" antigens/self-tolerance Self MHC proteins are recognized as foreign Usually restricted to specific tissues or organs
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Examples of Autoimmune Diseases? **
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Type I Diabetes Lupus Rheumatoid Arthritis
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What is Immune Deficiency Disorders Causes? **
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Congenital/Genetic disorder Bone marrow suppression- chemo & radiation Immunosuppressants- organ transplant rejections Immunodeficiency- AIDS, HIV
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HIV Immune Deficiency Disorder? ***
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Retrovirus; Reverse transcriptase: RNA → DNA Kills Helper T-Cells → ↓ immune response Typical infections prove lethal
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How does the immune system prevent cancer?
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Interferon enhances Macrophages, NK Cells & Cytotoxic T-Cells Macrophages → Phagocytosis Cytotoxic T-Cells & NK Cells → Release toxic chemicals → Attack or destroy cancer cells
