Ch 21/22: Lymphatic System and Immunity Practice Questions

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The thoracic duct and the right lymphatic duct empty lymph into the
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Terms in this set (172)
Primary lymphatic organs are responsible for the formation and maturation of lymphocytes; this includes red bone marrow and the thymus. Secondary lymphatic structures do not form lymphocytes, but they contain them. This is where the sites of immune response initiation occurs, and includes the spleen, tonsils, lymph nodes, and more.
-arranged in clusters to allow multiple rounds of lymph filtration
-multiple afferent vs. one efferent vessel increases pressure and pushes lymph through node
-arrangement of immune cells: cortex and medulla house various immune cells to monitor lymph (multiple cells count as one feature, answers that list B-cells and T-cells as two separate features will be given half credit)
-cortical sinuses lined with macrophages to phagocytize pathogens
-CT capsule encloses node for housing immune cells/filtering lymph
These are all examples of mechanical mechanisms that prevent entry of microorganisms into the body except:a. tears to wash the eyes b. saliva in the mouth c. skin d. cilia in the respiratory tract e. complement cascade EThis group of proteins is activated by a series of reactions, in which one activated chemical then activates another; and promotes inflammation, phagocytosis, and cell lysis:complementInterferons are antiviral proteins that stop viral reproduction in neighboring cells by preventing the production of viral nucleic acids and proteins.trueDust cells, microglia, and Kupffer cells are examples of these:macrophagesThis condition does not occur during the inflammatory response:a. histamine and other chemical mediators are released b. chemotaxis of phagocytes c. fibrinogen enters tissues from the blood d. vasoconstriction of blood vessels e. increased permeability of blood vessels DThis statement describes antigens:a. are foreign substances introduced into the body b. are molecules produced by the body c. stimulate an adaptive immune system response d. all of the above DThis statement describes the function of antibodies:a. prevent antigens from binding together b. promote phagocytosis c. inhibit inflammation d. block complement activation e. prevent breakdown of foreign antigens BThis statement describes B cells:are stimulated by helper T cellsThis best describes the activity of cytokines:a. promote inflammation b. activate macrophages c. kill target cells by causing them to lyseThese proteins are known as CD4 and CD8:attachment proteins on the surfaces of helper-T and cytotoxic T-cellsA vaccine produces its effects by this:stimulating a primary immune responseThis type of resistance is acquired as a result of developing and recovering from a disease:naturally acquired active immunityAntisera is available for microorganisms that cause this:a. rabies b. tetanus c. botulism d. black widow spider bitesPassive natural immunity results from the transfer of antibodies from a mother to her child across the placenta before birth.trueBooster shots are given some time after the original dose was administered for these purposes except:a. stimulates a secondary (memory) response b. large amounts of antibodies are formed c. the original dose has worn off d. provides longer-lasting immunity CThis statement best describes neutrophils:b. account for most of the dead cells in pusComplement is involved in this:both adaptive and innate immunityThis is an example of innate immunity:a. tears and saliva wash away microorganisms b. basophils release histamine and leukotrienes c. neutrophils phagocytize a microorganism d. activation of the complement cascadeThis antibody accounts for 80-85% of serum antibodies, can cross the placenta, and is responsible for Rh reactions:IgGAs the result of a bee sting, Joe B. Hive had an immediate severe reaction, and nearly died. This reaction was caused byB cellsElimination of an antigen stops the production of antibodies in this manner:a. antigens cannot combine with MHC class II molecules b. no signal to cause lymphocytes to proliferateCheck all that are components of lymphinterstitial fluid, solutes, foreign materialTrace the path of lymph from the time it leaves the interstitial spaces to the time it enters the blood.1. lymphatic capillaries 2. afferent lymphatic vessels 3. lymph nodes 4. efferent lymphatic vessels 5. lymphatic trunks 6. lymphatic ductsMatch the lymphatic trunk with the major body region that it drains.intestinal trunks- drain most abdominal structures lumbar trunks- drain lower limbs and pelvic organs jugular trunks- drain head and neck bronchomediastinal trunks- drain deep thoracic structures subclavian trunks- drain upper limbs, breasts, and thoracic wallWhich lymphatic ducts receive lymph from the body regions in the figure?All lymphocytes originate in the _______ bone marrow.redTonsils from superior to inferiorpharyngeal tonsil palatine tonsil lingual tonsilMatch the lymphatic organ with its descriptionthymus- site of T-lymphocyte maturation lymph node- filters lymph spleen- filters blood, storage of platelets and erythrocytesCorrectly label the anatomical features of lymphatic capillaries.Correctly label the following anatomical features of the lymph node.Indicate whether the given direction of lymph flow is correct or incorrect.Complete each sentence by dragging the proper label into the appropriate position. Not all terms will be used. Fluid contained inside the lymphatic vessels is referred to as ______ and is similar to ________ in consistency and appearance. Originating distally in the tissues of the body, excess interstitial fluids are taken up by the _________, which resemble ________. Accumulations of lymphocytes embedded in connective tissue networks are called _________ and can be present in static locations or acutely accumulate in areas of infection. The tonsils, spleen, thymus, and lymph nodes are all examples of _________.lymph blood plasma lymphatic vessels veins lymphatic tissues lymphatic organsPut the steps in the lymphatic pathway in the correct order.1. lymphatic capillary 2. afferent lymphatic vessel 3. lymph node 4. efferent lymphatic vessel 5. lymphatic trunk 6. collecting duct 7. subclavian veinLabel the structures of the spleen.Put the locations of origin, development, and action of lymphocytes in order.Insert the correct words into the sentences to demonstrate your understanding of the movement of fluid into lymphatic capillaries. Not all terms will be used. Fluid moves into lymphatic capillaries when there is a(n) _______ in hydrostatic pressure within the interstitial space. Interstitial hydrostatic pressure ______ as fluid is filtered from the blood capillaries. The higher the interstitial fluid pressure, the ________ amount of fluid that enters the lymphatic capillary.increase rises greaterClassify the tissues and organs as being either primary or secondary lymphatic structures. MALT Thymus Lymph nodes Tonsils Spleen Red bone marrowClassify the descriptions into the appropriate categories regarding the two major types of lymphocytes. a. Migrate to the thymus to mature b. Form in red bone marrow and directly enter the bloodT-lymphocytes- migrate to the thymus to mature B-lymohocytes- form in red bone marrow and directly enter the bloodInsert the correct words into the sentences regarding the structure and the function of the thymus. The thymus functions in __________ maturation. The thymus consists of ____ lobes. The cortex contains _________ lymphocytes. The inner medulla contains _______ lymphocytes.T-lymphocyte two immature matureInsert the correct words into the sentences regarding the functions of the spleen. The spleen functions to filter _______. The white pulp of the spleen contains ____________. The red pulp of the spleen contains ___________. The ________ serves as a reservoir for platelets.blood lymphatic cells macrophages red pulpInsert the correct words into the sentences regarding the characteristics of lymph. Approximately _____ of the fluid that enters the interstitial space is normally absorbed into lymphatic capillaries. The majority of lymph is composed of ___________. Occasionally lymph can contain metastasized _______.15% water and dissolved solutes cancer cellsInsert the correct words into the sentences regarding the locations and function of tonsils. Palatine tonsils are located in the posterolateral region of the ________. A pharyngeal tonsil is found in the posterior wall of the ___________. When the pharyngeal tonsil becomes enlarged, it is called ___________. Lingual tonsils are located along the posterior one-third of the _______. Within the tonsils are __________ that help protect against foreign substances.oral cavity nasopharynx adenoids tongue lymphatic nodulesWhat are the anatomic characteristics of lymphatic vessels? Check all that apply.Larger diameter than blood capillaries Lack a basement membrane Blind-ended Have anchoring filamentsLymph from the right lymphatic duct drains which areas of the body? Check all that apply.right side of the head and neck right upper limb ride side of thoraxWhat areas drain lymph through the thoracic duct? Check all that apply.left side of head and neck left upper limb left thorax all of abdomen and both lower limbsIn an adult, where is red bone marrow found in the body? Check all that apply.proximal epiphyses of each humerus and femur vertebrae and ribs flat bones of skull and sternumWhat are the typical structural parts of a lymph node? Check all that apply.lymphatic nodules afferent and efferent lymphatic vessels cortex and medulla of a noduleWhat are the main groups of tonsils in the body? Check all that apply.pharyngeal palatine lingualAs T-lymphocytes leave the thymus, they arenaive and immunocompetentA secondary response to an infectious agent has a ________ latent phase than a primary response has.shorterWhich type of cell produces and secretes antibodies?plasma cellExplain the necessity for both innate and adaptive immune systems (include examples).The innate immune system is non-specific and responds generally to any pathogens trying to enter the body or that have already entered. Non-specific defenses would include preventing entry (skin and mucous membranes), inflammation, immune cells, fever, and antimicrobial proteins. Adaptive immunity grows and learns over time with exposure to pathogens, it's what gives us our ability to develop immunity to certain diseases. Adaptive immunity is driven by the activity of B- and T-lymphocytes which monitor the body for infected cells or infectious agents.Helper T-cells require two signals to be activated. How are Tregs (regulatory T-cells) formed and what is their importance in the immune response?Tregs are formed when the CD4's of a TH recognize self-antigens to a moderate degree during the negative selection process, or when a TH does not receive the second signal (IL-2) after binding an APC. Tregs are necessary to slow down or stop the immune response before it causes an autoimmune reaction, a process known as peripheral tolerance.The ________________ cell encounters and processes the antigen. With the antigen, the antigen-presenting cell migrates to the nearest _______. The antigen-presenting cell displays the antigen to the __________. If the antigens are viral proteins or abnormal antigens, the T-lymphocytes initiate the ____________. Infected or malignant cells are then _________ before they can do further harm to the body.antigen presenting cell lymph node t-lymphocytes immune response destroyedWhen a person is exposed to an antigen for the first time the immune reaction is called the ________ response. The appearance of protective __________ is delayed for 3-6 days while naive B cells multiply and differentiate. As the plasma cells begin secreting antibody, the antibody ________ begins to rise. Eventually the primary response will make an immune ________ of the antigen.primary antibodies titer memoryAn immunoglobulin molecule is a _____, soluble ________ composed of four polypeptide chains: two identical heavy chains and two ________ light chains, with flexibility at the hinge region of the two ________ chains. These four polypeptide chains are held together by ___________ bonds to form an antibody monomer. Two important functional regions of the antibody monomer are the variable regions and the ________ region.Y-shaped protein identical heavy disulfide constantAny molecule that triggers an immune response is called a(n) ________. Venoms and toxins are ___________________ while others are components of ____________ or bacterial cell walls. The uniqueness of antigen molecules helps prevent the immune system from attacking ____________. The regions of antigens that trigger immune responses are called _________.antigen free molecules plasma membranes self antigens epitopesDrag each label into the appropriate position to identify what cell type is described by the label. capable of producing memory cells differentiate into plasma cells when activated can become antibody producing factories lymphocytes mature in thymus direct activation produced by MHC-II recognition arise originally from bone marrow can produce lethal hits to infected self-cells direct activation produced by MHC-I recognition most numerous lymphocyteT-lymphocytes- can produce lethal hits to infected self-cells, direct activation produced by MHC-I recognition, mature in thymus, most numerous lymphocyte, direct activation produced by MHC-II recognition B-lymphocytes- differentiate into plasma cells when activated, can become antibody producing factories both- lymphocytes, arise originally from bone marrow, capable of producing memory cellsSelect all that are true regarding cytokines.-their actions are similar to hormones -they regulate immune cells -they include interleukinsClassify each description as associated with either cell-mediated or humoral immunity. - induces apoptosis - pathogens are tagged for destruction -lymphocytes kill infected cells directly - utilizes granzymes -plasma cells are involved - utilizes perforin - antibodies bind infected cellscell-mediated: lymphocytes kill infected cells directly utilizes granzymes utilizes perforin induces apoptosis humoral: antibodies bind infected cells pathogens are tagged for destruction plasma cells are involved__________________________ immunity occurs when the person is exposed to a _____ pathogen, develops the disease, and becomes immune as a result of the _________ immune response. ___________________ immunity can be induced by any substance that contains the antigen that is purposefully introduced into the body. Artificially acquired passive immunity is a __________ immunization by the injection of antibodies that are not produced by the recipient's cells. _______________________ immunity occurs during pregnancy, in which certain antibodies are passed from the maternal into the fetal bloodstream.Naturally acquired active live primary artificially acquired active artificially acquired passive short-term naturally acquired passiveClassify each characteristic with the appropriate cell. respiratory burst attack parasites release of granules of histamine first to arrive release of granules of heparin most abundantneutrophils- most abundant, first to arrive, respiratory burst basophils- release granules of histamine, release granules of heparin eosinophils- attack parasitesB-lymphocyte activation begins when antigens bind to several __________ on the B-lymphocyte. The antigen is taken into the cell by receptor-mediated ____________. The B-lymphocyte then processes the antigen, links some of the ___________ to its MHC-II proteins, and then displays it on the cell surface. A________________ binds to the Ag-MHC complex and secretes interleukins that activate the B-lymphocyte and trigger __________ selection. Most cells of the clone differentiate into ___________ cells and begin producing _____________.receptors endocytosis epitopes helper T-lymphocyte clonal plasma antibodieswhat is exudateThe fluid, protein, and immune cells that leave capillaries at the site of inflammation in tissueSelect all that occur during activation of cytotoxic T-lymphocytes.The TCR binds a peptide displayed with an MHC class I molecule of an infected cell. Clones of the cytotoxic T-lymphocyte are produced.Which of the following statements is true regarding memory in humoral immunity? Check all that apply.Memory B-lymphocytes are found mainly in the lymph nodes.Label the figure with the items provided.costimulation to activate T-lymphocytes for clonal selection1. CD4/TCR binds presented antigen 2. Helper T-lymphocyte releases Il-2 as an autocrine signal 3. clones of activated and memory helper T-cells are producedInterleukin-2 acts as a(n) _________ hormone for helper T-lymphoctyes, causing the cell that released it to form clones.autocrinenonspecific resistance examplesskin a fever as a result of a bacterial infection natural killer cells patrol the body on the lookout for diseased host cells the inflammatory responseimmunity examples- producing an antibody against a cold virus - a tetanus vaccine stimulates the body to produce antibodies against the bacteria - antibodies pass from the placenta into the fetus - receiving anti-venom after being bitten by a rattlesnakeWhen ____________ T-lymphocytes recognize an antigen presented by an infected cell (with MHC ________ molecules), they destroy the cell by releasing granules containing cytotoxic chemicals. The first cytotoxic chemical, _________ forms channels in target cell membranes. This increases the cell's ____________. Induction of cell ___________, which helps to limit spread of the infectious agent, is initiated by _________. It is because the immune response of __________ is effective against antigens associated with cells that it is referred to as ___________ immunity.cytotoxic class I perforin permeability death by apoptosis granzymes T-lymphocytes cell-mediatedSelect all that are categories of cytokines.interleukins interferons tumor necrosis factor colony stimulating factorSelect all that are true regarding receptors on T-lymphocytes.different co-receptors can be present CD molecules act as co-receptorsThe display of an antigen on a cell surface is known as _______ ________.antigen presentationSelect all that are part of T-lymphocyte development.migrate to thymus T-lymphocyte selection produced in red bone marrowAn immune cell is observed to present antigen to naive helper and cytotoxic T-lymphocytes. Using this information, select all that apply.the cell is an antigen presenting cell may be a macrophage may be dendritic cell may be B-lymphocyteOrder the events of formation and display of MHC class I molecules in an infected cell.formation - proteasome digests viral proteins - MHC class I molecules bind viral antigens in RER - vesicles carry MHC class I molecules to golgi apparatus - secretory vesicles carry MHC class I molecules to plasma membrane displayhigh immunogenicityforeign large high quantity complex shapelow immunogenicityself-antigen small low quantity simple shapeactive vs passive immunityactive- requires direct contact with antigen, memory cells develop passive- receives antibodies from another individual, no antigenic challenge, no memory cells produced, lasts only as long as antibodies are present in bodyPlace the events that occur with fever in the correct sequence.- pyrogens are released and circulate in the blood - hypothalamus stimulates blood vessels in the dermis to constrict - blood vessels vasoconstrict - body temp rises - elevated temp is maintained - metabolic rate increases - minerals released by the liver and spleen to slow microbial reproduction - decreased stimulation of the hypothalamus - temperature returns to normal set pointPlace the events of lymphocyte maturation in the correct sequence.- primary lymphatic structures produce lymphocytes - pre T-lymphocytes - lymphocytes mature in primary lymphatic structures - naive immunocompetent T-lymphocytes - lymphocytes migrate and are house in secondary lymphatic structures - lymphocytes proliferate and are activated - T-lymphocytes carry out effector functions - foreign antigens are eliminatedClassify each cytokine function within the appropriate category. regulates immune cells antiviral agent destroys tumor cells ormolus inflammationinterleukin interferon tumor necrosis factor interferonClassify each effector response as associated with either helper T-lymphocytes or cytotoxic T-lymphoctyes. release perforin directly kill infected cells release cytokines release granzymeshelper- release cytokines cytotoxic- all of themCategorize the following as a risk or benefit due to a fever.risk- increased protein denaturation, possible seizures, irreversible brain damage is greater than 106, death likely if greater than 109 benefits- decreased replication of pathogens, increased interferon activity, increased adaptive immune activity, increased tissue repairPlace the events of the lifetime of a lymphocyte in the correct sequence.-formation and maturation in red bone marrow and thymus - become able to recognize only one specific foreign antigen - migration to spleen, tonsils, lymph nodes, and MALT - have first exposure to antigen in which they bind - replicate to make identical cells - effector functions carried out to eliminate pathogensphysical barrier vs chemical mediatorphysical- prevent microorganisms from entering body chemical- kill microorganisms, promote inflammationrecirculationThe tendency for lymphocytes to reside only temporarily in a lymphatic structure, and circulate to different areas through the blood and lymphPlace the events that occur during the effector response of cytotoxic T-lymphocytes in the correct sequence.- antigen is presented to T-lymphocytes in secondary lymphatic structures - cytotoxic T-cells migrate to site of infection - activated cytotoxic T-cell contacts an infected cell at site of infection - cytotoxic T-cell releases perforin and granzymes - apoptosis of infected cellCheck all that occur during inflammation.chemical mediators cause vasodilation fibrin walls off the infected area complement attracts phagocytes to the areaClassify each cytokine with the cell(s) that release it. Terms may be placed within more than one category. fibroblasts t-cells monocytes macrophagesinterleukin- t-lymphocytes, macrophages tumor necrosis factor- t-lymphocytes, macrophages colony stimulating factor- t-lymphocytes, monocytes interferon- t-lymphocytes, fibroblastsIgGimmunoglobulin G; 75-85% of antibodies - passive immunity - longest half-life - most abundant - found in bloodIgM-pentameter - produced in fetus - found in blood - first antibodyIgA- found in external secretions - mucous membranes (mucus, saliva, tears, breastmilk) - good at agglutinationIgD- part of B-lymphocyte receptor - identifies when immature B-cells are ready for activationIgE- formed during allergic reactions - causes degranulation of basophils - causes degranulation of mast cells - found in bloodclassic pathwaya complement protein binds to a(n) antibody that has previously attached to a foreign substance - antibody requiredalternative pathwaysurface polysaccharides of certain bacterial and fungal cell walls bind directly with a complement protein - antibody not required for activationimmunogenicityA particular virus strain is highly effective in activating an immune responseAfter leaving the thymus, T-lymphocytesare naive and immunocompetentCells of innate immunity- phagocytes: neutrophils, macrophages, dendrites - pro-inflammatory: basophils, mast cells apoptotic: NK cells parasite destroying: eosinophilsinflammation process1. release of inflammatory/chemotactic factors 2. vascular changes include: vasodilation of arterioles, increase in capillary permeability, display of CAMs 3. recruitment of WBC; margination, diapedesis, chemotaxis 4. delivery of plasma proteins3 stages of feveronset, stadium, defervescencepro-inflammatoryrelease different chemicals (histamines, bradykinans) to increase fluid flow, to help move more fluid to an infected area; more WBC and plasma proteins coming for healing and repairapoptoticcell shriveling/death; will release chemicals that will cause cells to shrivel up on itself and then a macrophage will eat it so it doesn't release any infected particlescomplementaround 30 proteins; released to help mitigate the immune system; helps effect of antibodies - synthesized by liver, continuously released in inactive form; activation occurs by enzyme cascadeb-lymphocytes can: t-lymphocytes cannot:dont have to be presented with antigen; can bind directly to the pathogen bind directly to the antigen; has to have another cell become infected and then present infected antigens to T-cellmemory cellA lymphocyte that responds to an antigen upon reintroductionCytotoxic T cellsA type of lymphocyte that kills infected body cells and cancer cells; apoptosis inducingCD8 vs. CD4 cellscytotoxic T-cell vs. helper T-cellCytokines: Chemical Messengers of Immune CellsChemicals/proteins released that help regulate immune response chemical messengers released from one cell that bind to receptors of target cells - can act on cell that released it (autocrine), on local cells (paracrine) or on distant cells after circulating through blood (endocrine)goal of Tregsto make sure you do not have an inappropriate immune responseall helper T-cells have _____; all cytotoxic have _____, every T-cell has a different ______CD4+, CD8+, TCR (except for memory ones)herd immunitythreshold when enough people in the population have antibodies/resistance to pathogen, considered no longer spreading within populationepithelial layers of skin and mucosal membranes housedendritic cells (usually derived from monocytes); engulf pathogens and migrate into lymphconnective tissue housesmast cells; typically in close proximity to small blood vessels - abundant in dermis and mucosa of respiratory and Gi tractsinnate and adaptive immunity differ based on- cells involved - specificity of cell response - mechanisms of eliminating harmful substances - amount of time for responseinnate immunity first and second lines of defense1st- skin and mucosal membrane 2nd- internal processes - activities of neutrophils, macrophages, dendritic cells, eosinophils, basophils, and NK cells - chemicals such as interferon and complement - physiological processes such as inflammation and feverhistamine and heparinreleased by basophils and mast cells: histamine- increases vasodilation and capillary permeability heparin- acts as an anticoagulantinterferonsA class of chemicals that block viral infections IFN-a and IFN-b produced by leukocytes and virus-infected cells (bind to neighboring cells and prevent their infection); stimulate NK cells to destroy the virus-infected cells IFN-g produced by T-lymphocytes and NK cells - stimulates macrophages to destroy virus-infected cellseffects of activated complementopsonization: opsonin binds to pathogen, enhances likelihood of phagocytosis of pathogenic cell inflammation: activates mast cells and basophils, attracts neutrophils and macrophages cytolysis: triggers splitting of target cell; form membrane attack complex (MAC) that creates channel in target cell's membrane, fluid enters, cell lysis elimination of immune complexes: links antigen-antibody complexes to erythrocytes, cells move to liver/spleen where complexes are stripped offeffects of inflammation1. fluid (exudate) moves from blood to injured or infected area (to eliminate pathogens and promote healing) 2. vasodilation brings more blood to area 3. increase in capillary permeability 4. loss of plasma proteins, decreases fluid reabsorption into blood 5. extra fluid is "washed;" debris carried away and allows lymph node monitoring of its contentsIf you are dehydrated, how does that impair your healing?Water is a major component of blood, and dehydration reduces the body's blood volume. This reduces oxygen and nutrient delivery to the wound bed and impairswound healing.cardinal signs of inflammationredness- increase blood flow heat- from increased blood flow and metabolic activity within the area swelling- from increase in fluid loss from capillaries pain- from stimulation of pain receptorsfever1 degree or more Celsius higher than normal (37) - results from the release of pyrogens from immune cells or infectious agentsevents of a fever1) Pyrogens circulate through blood and target hypothalamus 2) In response, hypothalamus releases prostaglandin E2 3) Hypothalamus raises temperature set point leading to feverstages of a feveronset: temp begins to rise; hypothalamus stimulates constriction of dermal BV (less heat loss); shivering of muscle generates more heat stadium: elevated temp is maintained: metabolic rate increases to promote elimination of harmful substance; liver and spleen bind zinc and iron defervescence: time when temp returns to normal; hypothalamus no longer stimulated; prostaglandin release decreases; vasodilation of skin blood vessels, sweatingWhy is it recommended to leave a low fever untreatedPeople with high fevers will take ibuprofen/Tylenol to suppress the fever, their body is still fighting infections and has an increased metabolic activity and you are out living your life because you feel fine, but you're actually doubling up the work on your body which makes the healing slower and makes you feel even worse - Its best to let yourself rest when you are sick so its not working double overtimeantigenic determinantepitope; specific site on antigen recognized by immune system; each has a different shapehaptensToo small to be immunogens by themselves but become immunogenic after combining with larger molecules that function as carriers for the haptens example: toxin in poison ivyantigen presentationcells display antigen on plasma membrane so T-cells can recognize it2 categories of cells present antigens1. all nucleated cells of the body 2. antigen presenting cells (APCs) - immune cells that present to both helper T-cells and cytotoxic T-cells (dendritic, macrophages, B-lymphocytes) can be 1 without 2, but if you are 2, you are also going to be 1MHC class I-glycoproteins -synthesized in RER; then inserted into cell membrane -genetically determined structure that is unique to individual - all nucleated cellsMHC class I molecules display ____fragments of proteins that were bound in RER - if they are from endogenous proteins, immune system recognizes them as self and ignores them - if from infectious agent, considered "non self;" communicates to cytotoxic T-cells that they should destroy cellMHC class II moleculesONLY FOUND ON ANTIGEN PRESENTING CELLS->dendritic cells, macrophages, and B cells->Thymic selectioneliminates immature T cells (98%)positive selectionSelects for the ability of T-cells to bind thymic epithelial cells with MHC molecules (those that can bind survive) if it binds, it survivesnegative selectionTests ability of T-lymphocyte to NOT bind self-antigens (self-tolerance) - thymus dendritic cells present self-antigens and T-cells that bind to them are destroyed if it binds, it gets destroyedT-lymphocytes differentiatehelper T-cells lose CD8 protein, keep CD4 cytotoxic T-cells lose CD4 protein, keep CD8antigen challengefirst encounter between an antigen and a naive immunocompetent cell - usually occurs in secondary lymphatic structuresHelper T cell activationonly bind APC's 1st signal: MHC II binds TCR and CD4 protein; if CD4 binds, it strengthens the bond even more 2nd signal: after several hours; helper T cell releases IL-2, which activates more helper t cells and creates memory helper t cells (which have the same TCR as the one that's binding)cytotoxic T cell activationbind APC's and nucleated cells 1st signal: MHC I binds TCR/CD8 2nd signal: IL-2 from helper t cells activate the cytotoxic cells and create memory cytotoxic T cellsB-cell activationbind directly to antigen; no antigen presentation 1st signal: antigen binds BCR 2nd: IL-4 from Helper T-cells creates memory B-cells and plasma cells (antibodies) *** may not go past 1st step; has to get 2nd signal firstexamples of natural and artificial active immunitynatural: direct exposure to pathogen artificial: vaccine (intentionally exposed) leads to herd immunityexamples of natural and artificial passive immunitynatural: breast milk (rich in IgGs) artificial: serum (antibiotics) (plasma without clotting proteins)this statement best describes the function of antibodies:promote phagocytosisantibody functions:neutralization: antibody covers biologically active portion of microbe or toxin agglutination: antibody cross-links cells, forming a clump precipitation: cross-links circulating particles forming an insoluble antigen antibody complex complement fixation: Fc region of antibody binds complement proteins, complement is activated opsonization: Fc region of antibody binds to receptors of phagocytic cells triggering phagocytosis activation of NK cells: Fc region binds to an NK cell which triggers release of cytotoxic chemicalsantibody titeramount of antibody in serum initial exposure: active infection or vaccine primary response: antibody production to first exposureinfectious agents pathogenic agentscan damage or kill a host ones that cause harmfive major categories of infectious agentsbacteria, viruses, fungi, protozoans, and multicellular parasitesbacteria-single celled - most are harmless; some virulent (cause serious illness) - virulent bacteria may have pili, capsule, or release toxins or damaging enzymes -example: Clostridium tetani, streptococcusviruses- pieces of DNA or RNA in a protein shell - not cells, but obligate intracellular parasites (direct infected cell to make copies of nucleic acid and capsid (shell)) - virus or immune response may kill the host cell - example: common cold, ebola, chickenpoxfungi- eukaryotic cells with membrane and cell wall - include molds, yeasts, multicellular fungi that produce spores - release proteolytic enzymes inducing inflammation - cause superficial diseases in the integument (ringworm) - can infect mucosal linings (yeast infections)protozoans- eukaryotic cells without a cell wall - intracellular and extracellular processes - examples malaria and trichomoniasis - multicellular parasites are non-microscopic; take nourishment from host they live in (tapeworm)prions- fragments of infectious proteins - neither cells nor viruses - cause disease in nervous tissue - example: Variant Creutzfeldt-Jakob disease (mad cow disease)marginationadherence of leukocytes to endothelial CAMsdiapedesiscells escape blood vessel walls (moving through cell walls)chemotaxisleukocyte migrate toward chemicals released from dead, damaged, or pathogenic cells - leukocytes release cytokines stimulating leukopoiesis in marrow - macrophages may release pyrogens (fever-inducing molecules)Activation of helper T cells1st signal: CD4 binds with MHC class II molecule of APC; TCR interacts with antigen within MHC class II molecule 2nd signal: other receptors interact and the help T-cell releases IL-2, which binds with the helper T-cell Activated helper T-cell proliferates and differentiates to form a clone of activated and memory helper T-cellsactivation of cytotoxic T-cells1st signal: CD8 binds with MHC class I molecule of infected cell; TCR interacts with antigen within MHC I molecule 2nd signal: IL-2 released from activated helper T-cell activates cytotoxic T-cells activated cytotoxic T-cell proliferates and differentiates to form a clone of activated and memory cytotoxic T-cellsprimary response lag/latent phase production of antibodyantibody production to first exposure lag phase- initial period of no detectable antibody; lasts 3-6 days; includes antigen detection, activation, proliferation, differentiation production of antibody- plasma cells produce IgM and then IgG; occurs within 1-2 weeks; antibody levels peak, then decline over time