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APHY 201 Exam 3c
Ch. 15 The Immune System
| Question | Answer |
|---|---|
| What are the three categories of internal innate defenses? | Protective proteins, protective cells, and protective processes. |
| What enzyme found in mucous membranes destroys bacteria by dissolving their cell walls? | Lysozyme. |
| What toxic chemicals are produced during a neutrophil's respiratory burst to create a "killing zone"? | Superoxide anion (O2-), hydrogen peroxide (H2O2), and hypochlorite (HClO). |
| What two key chemicals do basophils release to assist white blood cell mobility and action? | Histamine (a vasodilator) and heparin (an anticoagulant). |
| How do natural killer (NK) cells target and lyse cancerous or virally infected host cells? | They release perforin proteins to make holes in the target membrane and then inject protein-degrading granzymes. |
| Which organ is responsible for synthesizing most of the proteins in the complement system? | The liver. |
| What endogenous pyrogen is released from the anterior hypothalamus to reset the body's thermostat higher during a fever? | Prostaglandin E2 (PGE2). |
| What severe condition can be triggered if a child is given aspirin following an acute viral infection like chickenpox or influenza? | Reye syndrome. |
| What cell adhesion molecules are produced by endothelial cells to facilitate leukocyte margination along blood vessel walls? | Selectins. |
| Which leukocyte acts as the primary agent of tissue cleanup, arriving 8 to 12 hours after injury to become macrophages? | Monocytes. |
| What cytokine is secreted by blood platelets and endothelial cells to stimulate fibroblasts to multiply and synthesize collagen for tissue repair? | Platelet-derived growth factor (PDGF). |
| reason 1 self-tolerance may fail | an antigen not normally circulating in blood may be exposed to the immune system ex) Hashimoto's; breakdown of blood-testis barrier |
| reason 2 self-tolerance may fail | a tolerated self-antigen may be altered by combining with foreign haptens such as drugs combining with platelet proteins, forming new antigens |
| reason 3 self-tolerance may fail | antibodies directed against other antibodies (imbalance) ex) rheumatoid arthritis |
| reason 4 self-tolerance may fail | antibodies produced against foreign antigens may cross-react with self-antigens ex) after strep infection |
| reason 5 self-tolerance may fail | self-antigens (receptors) may be presented to T helper cells together with MHC-II molecules ex) Graves' disease; type 1 diabetes mellitus |
| reason 6 self-tolerance may fail | autoimmune disease resulting from inadequate T regs cells. |
| what is clonal selection theory? | that B lymphocytes inherit the ability to produce particular antibodies, and T lymphocytes inherit the ability to respond to particular antigens. ex) genes that respond to smallpox w/o prior exposure |
| what is the history of adjuvants? | molecules discovered to be able to boost the immune response when delivered together with the vaccine antigens. adjuvants are generally associated with microbes |
| what are adjuvants? | molecules among the PAMPs (pathogen-associated molecular paterns) that activate the innate immune system. they boost the ability of APCs to activate B and T lymphocyte responses |
| why do adjuvant benefits occur? | because dendritic cells, critically important in the adaptive immune response, contain receptors that bind to PAMPs and DAMPs (damage-associated molecular patterns) |
| what is the term for incomplete/partial joint dislocation? | subluxation |
| the sympathetic nervous system issues nerve fibers to which immune-related, and thus indirectly nervous system-related, organs? | spleen, thymus, lymph, Peyer's patches |
| what are 4 reasons autoimmune disease occur? | failure of self-tolerance and production of autoantibodies, cross-reactivity, abnormal exposure of self-antigens to blood (BTB breakdown), changes in structure of self-antigens (viruses or drugs) |
| what is the immunologically privileged site in the body where Sertoli cells produce FAS ligand molecule to trigger apoptosis of any T-lymphocytes coming into the area | blood-testis barrier |
| which hypersensitivity is a T cell-mediated immune response? | type IV (delayed hypersensitivity) ex) poison ivy and cosmetic haptens |
| which hypersensitivity is an immune complex associated w/widespread antigen-antibody complexing as well as intense inflammation, i.e. acute glomerulonephritis; systemic lupus erythematosus? | type III |
| which hypersensitivity is associated with antibody-dependent cytotoxicity that can be autoimmune, alloimmune or drug-induced? e.g. transfusion reaction, pemphigus vulgaris, myasthenia gravis or toxic goiter? | type II |
| how does type II hypersensitivity work? | IgG or IgM either binds to cells' antigens and lyses them through complement fixation, or binds to cell surface receptors and a) interferes with cell function or b) overstimulates the cell |
| what is urticaria? | hives, occurs in type I hypersensitivity |
| What is the difference between natural active immunity and artificial active immunity? | Natural active immunity comes from natural exposure to an antigen/infection, while artificial active immunity comes from a vaccination; both produce memory cells. |
| What is the difference between natural passive immunity and artificial passive immunity? | Natural passive immunity involves a fetus acquiring maternal antibodies through the placenta or milk, while artificial passive immunity involves an injection of immune serum/antibodies to treat immediate threats like snakebites or rabies. |
| What are the three major types of lymphocytes in circulating blood and their relative percentages? | 80% T cells (specific, cell-mediated), 15% B cells (specific, antibody-mediated), and 5% natural killer (NK) cells (nonspecific/innate defense). |
| Where are fetal T lymphocytes "born," and where do they go to mature or "go to school"? | They are born in the red bone marrow (differentiated from pluripotent stem cells) and mature in the thymus. |
| What two conditions must immunocompetent T cells meet during selection in the thymus to pass "the quiz"? | They must recognize (bind to) the MHC proteins of reticular endothelial cells and must not react to self-antigens. |
| What are the two mechanisms of negative selection for T cells that fail the thymus quiz? | Clonal deletion (destruction of offending T cell clones) and anergy (leaving them alive but inactivated/unresponsive). |
| What are the major development sites for fetal B lymphocytes? | The liver, bone marrow, junction of the small and large intestine, and the appendix. |
| What are the four functional classes of T cells involved in cellular immunity? | Cytotoxic T (TC, CD8) cells, Helper T (TH, CD4) cells, Regulatory T (TR, T-regs) cells, and Memory T (TM) cells. |
| On which cells are MHC-I proteins found, and which specific class of T cells recognizes them? | They are found on nearly all nucleated somatic body cells and are recognized by Cytotoxic T (TC, CD8) cells. |
| On which cells are MHC-II proteins found, and which specific class of T cells responds to them? | They are found only on antigen-presenting cells (APCs) and are recognized exclusively by Helper T (TH, CD4) cells. |
| What three chemical/protein weapons do Cytotoxic T cells release to destroy target cell membranes and inhibit viruses? | Perforin, granzymes, and interferons (along with tumor necrosis factor). |
| What two activation steps must occur before a B cell divides repeatedly and differentiates into antibody-secreting plasma cells? | B cell receptors must bind an antigen (ingesting and displaying epitopes on its MHC-II protein) and it must undergo costimulation by a patrolling Helper T cell releasing interleukins. |
| Which antibody class exists as a dimer in mucus, saliva, tears, and milk to prevent pathogen adherence to epithelia? | IgA |
| Which antibody class stimulates the release of histamines, attracts eosinophils, and is responsible for immediate hypersensitivity allergic reactions? | IgE |
| Which antibody class makes up 75-85% of circulating antibodies, can cross the placenta, and dominates the secondary (anamnestic) immune response? | IgG |
| Which antibody class acts as a pentamer in plasma, is the first secreted during a primary immune response, and handles ABO blood group agglutination? | IgM |
| What three mechanisms allow for the massive structural diversity of human antibodies? | Somatic recombination (shuffling DNA segments), somatic hypermutation (high mutation rates in germinal centers), and class switch recombination. |
| What are the four primary methods antibodies use during the "attack" phase of humoral immunity? | Neutralization, complement fixation, agglutination, and precipitation. |
| What hereditary defect characterizes Severe Combined Immunodeficiency Disease (SCID)? | A complete lack of both T cells and B cells, leaving the individual highly vulnerable to opportunistic infections. |
| What specific cells does the Human Immunodeficiency Virus (HIV) invade and destroy? | Helper T cells (CD4 cells), macrophages, and dendritic cells. |
| At what specific threshold does a normal TH count drop to officially diagnose clinical AIDS? | Below 200 cells/mm^3 of blood (normal is 600 to 1,200 cells/mm^3). |
| How does the drug AZT work to treat HIV/AIDS? | It treats HIV by inhibiting the viral reverse transcriptase enzyme. |
| What process allows new phagocytic leukocytes (neutrophils and monocytes) to leave blood vessels and invade an infected tissue area? | Extravasation (diapedesis). |
| How long does it take to develop resistance via active immunity versus passive immunity? | Active immunity takes 5 to 14 days to develop, while passive immunity provides resistance immediately. |
| What type of lymphocytes, immune effectors, and therapies are characteristic of a delayed hypersensitivity allergy reaction? | T cells, cell-mediated immunity, and corticosteroid (like cortisone) therapies. |
| What are broadly effective defenses that require no prior exposure to a pathogen? | Nonspecific (innate) defenses. |
| What type of immunity results from prior exposure and protects against only a particular pathogen? | Specific (adaptive) immunity. |
| What external barrier features the toughness of keratin, a dry and nutrient-poor surface, and a lactic acid mantle? | Skin. |
| What are peptides from neutrophils that attack and destroy microbes by boring holes in their membranes? | Defensins. |
| What enzyme found in mucous membranes destroys bacteria by dissolving their cell walls? | Lysozyme. |
| What tissue forms a viscous tissue gel barrier of hyaluronic acid? | Subepithelial areolar tissue. |
| What enzyme is used by some pathogens to break down the hyaluronic acid tissue gel to spread? | Hyaluronidase. |
| What leukocytes phagocytize bacteria and create a killing zone through degranulation and a respiratory burst, ultimately dying in the attack? | Neutrophils. |
| What process triggers the creation of toxic chemicals like superoxide anion, hydrogen peroxide, and hypochlorite to kill bacteria? | Respiratory burst. |
| What leukocytes phagocytize antigen-antibody complexes and allergens, and release enzymes for antiparasitic effects? | Eosinophils. |
| What leukocytes aid the mobility and action of white blood cells by releasing the vasodilator histamine and the anticoagulant heparin? | Basophils. |
| What circulating blood cells are the precursors to macrophages? | Monocytes. |
| What large lymphocytes lyse cancerous or virally infected host cells by releasing perforin proteins and granzymes as a nonspecific defense? | Natural killer (NK) cells. |
| What polypeptides are secreted by virus-invaded cells to stimulate neighboring cells to produce antiviral proteins and activate NK cells and macrophages? | Interferons. |
| What group of blood proteins, synthesized mostly by the liver, must be activated by pathogens to enhance inflammation, immune clearance, and phagocytosis? | Complement system. |
| Which pathway of complement activation requires antibody action? | Classical pathway. |
| Which pathway of complement activation requires no antibodies and acts as a nonspecific defense? | Alternate pathway. |
| What ring formed by complement proteins C5b to C9 in the plasma membrane of an enemy cell causes cytolysis? | Membrane Attack Complex (MAC). |
| What defense mechanism promotes interferon activity, accelerates metabolic rate and tissue repair, and inhibits pathogen reproduction? | Fever (pyrexia). |
| What general term describes fever-producing agents, which can be exogenous or endogenous? | Pyrogens. |
| What endogenous pyrogen from the anterior hypothalamus resets the body thermostat higher? | Prostaglandin E2 (PGE2). |
| What condition, which follows an acute viral infection like chicken pox and is triggered by aspirin, may result in death or mental retardation? | Reye syndrome. |
| What chemicals, secreted by damaged cells, basophils, and mast cells, stimulate vasodilation that leads to hyperemia? | Bradykinin, histamine, and leukotrienes. |
| What is the process where leukocytes adhere to blood vessel walls using cell adhesion molecules called selectins? | Margination. |
| What process allows leukocytes to squeeze between endothelial cells into the tissue space? | Diapedesis (emigration, extravasation). |
| What process involves leukocytes being attracted to inflammatory chemicals? | Chemotaxis. |
| What condition is characterized by a rapid increase in neutrophils to about 25,000 per microliter in response to infection? | Neutrophilia. |
| What are the primary agents of tissue cleanup that arrive in 8 to 12 hours from the blood? | Monocytes (which become macrophages). |
| What cytokine, secreted by blood platelets and endothelial cells, stimulates fibroblasts to multiply and synthesize collagen during tissue repair? | PDGF (platelet-derived growth factor). |
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