21 Lecture – Flashcards
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The body depends on 2 intrinsic defense systems that act both independently and cooperatively to provide resistance to disease or___________
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Immunity
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Name the 2 defense systems.
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Innate defense system & adaptive defense system?
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What is the first line of defense against disease?
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Surface barriers - Skin & mucous membranes, along with the secretions they produce.
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_______ is a functional system rather than an organ system in an anatomical sense.
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immune system
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1. All of the following are considered innate body defenses except _________. a) complement B) phagocytosis C) antibodies D) lysozyme E) inflammation
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antibodies
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2. The process by which neutrophils squeeze through capillary walls in response to inflammatory signals is called a) diapedesis b) chemotaxis c) margination d) opsonization
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diapedesis
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3. Antibodies that are released by plasma cells are involved in a) humoral immunity b) immediate hypersensitivity reactions c) autoimmune disorders d) all of the above
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all of the above
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4. Which of the following antibodies can fix complement? a) IgA b) IgD c) IgE d) IgG e) IgM
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IgM & IgG
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5. Which antibody class is abundant in body secretions? a) IgD b) IgE c) IgG d) IgM
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a - IgD
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6. Small molecules that must combine with large proteins to become immunogenic are called a) complete antigens b) kinins c) anitigenic determinants d) haptens
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d - haptens
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7. Lymphocytes that develop immunocompetence in the bone marrow are a) T lymphocytes b) B lymphocytes c) NK cells d) B & T lymphocytes
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b - B lymphocytes
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8. Cells that can directly attack target cells include all of the following except a) macrophages b) cytotoxic T cells c) Helper T cells d) natural killer cells
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c - Helper T cells
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9. Which of the following is not involved in the activation of a B cell a) antigens b) helper T cells c) cytokine d) cytotoxic T cell
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d - cytotoxic T cells
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10. The cell type most often invaded by HIV is a a) eosinophil b)cytotoxic T cell c) natural killer cell d) helper T cell e) B cell
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d - helper T cells
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Complement fixation promotes all of the following except a) cell lysis b) inflammation c) opsonization d) interferon release e) chemotaxis of neutrophils and other cells
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d - interferon release
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harmful or disease causing microorganisms
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pathogens
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Keratin of the skin is resistant to __________, ________, ________& _________.
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weak acids, bases , bacterial enzymes & toxins
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Name the second line of defense that is incorporated with the innate defense system.
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Innate internal defenses - cells & chemicals
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NK cells recognize abnormal or cancer cells by a specific antigen on their cell membrane.
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Which of the following is NOT a characteristic of Natural Killer (NK) cells?
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_________________ identify potentially harmful substances by recognizing ( binding tightly to) molecules with specific shapes that are part of infectious organisms (bacteria, viruses and fungi) but not normal human cells
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pattern recognition receptors
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Which of the following innate internal defenses work by interfering with viral replication?
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Interferons
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How do phagocytes recognize foreign cells or bacteria?
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The phagocytes recognize molecules on pathogens not normally found on body cells.
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Complement proteins
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Which of the innate defense mechanisms can lyse bacteria and mark cells for phagocytosis?
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Engulf and destroy pathogens that breach surface membrane barriers; macrophages also contribute to adaptive immune response.
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Phagocytes
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What is the correct order of phagocytosis a. phagocyte adheres to pathogens or debris. b. phagocyte forms pseudopods that eventually enguld the particles forming phagosome c. lysosome fuses with the phagocytic vesles, forming a phagolysosome d. toxic compounds and lysosomal enzymes destroy pathogens e. Sometimes exocytosis of the vesicle removes indigenstibel and residual material
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a, b, c, d, e
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Sometimes phagocytic attempts are unsuccessful. How does our immune system get around identifying the pathogens carbohydrate signature?
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By coating the pathogen with the complimentary protein opsonins (or antibodies)
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Which of the following can act as opsonins on bacteria, thus enhancing phagocytosis?
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Antibodies and compliment proteins
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What process greatly accelerates phagocytosis of a pathogen?
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opsonization
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The innate defense system has a 2 line of defense called the innate internal defense system. Name the internal defense mechanisms.
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Phagocytosis, Natural killers (NK cells), inflammation, antimicrobial proteins & fever
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How do NK cells aid the innate defense system.
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They eliminate infected or cancerous cells by detecting general abnormalities such as the lack of "self" a cell surface proteins called MHC.
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Lymphocytes of the adaptive immune system only recognize and react to specific viruses infected or tumor cells. What makes NK cells different.
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They are nonspecific, directly contacting target cell and inducing apoptosis.
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Name the 4 cardinal signs of inflammation.
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redness, heat, swelling & pain
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Inflammatory response
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1. Prevents injurious agents from spreading to adjacent tissues. 2, Disposes of pathogens and dead tissue cells promotes tissue repair 3. Released inflammatory chamicals attract phagocytes (and other immune cells) to the area
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What causes redness & heat when associated with inflammation.
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REDNESS & HEAT - vasodilation of arterioles, which increase the flow of blood to affected area
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Histamine
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1. Promotes vasodilation of local arterioles 2. Increases permeability of local capillaries
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What causes swelling when associated with inflammation.
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SWELLING- release of histamine and other chemical mediators of inflammation which increase capillary permeability. This allows proteins to leak into the interstitial fluid, increasing IF osmotic pressure and drawing more fluid out of blood vessels and into tissue, thereby causing swelling
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What causes pain when associated with inflammation
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1. The action of certain chemical mediators (kinins and prostaglandins) on nerve endings 2. The swelling which can compress free nerve endings.
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Mast cells are a key component of the inflammatory response. They release a chemical called ____________ which is a ___________.
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histamine, vasodilator
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Macrophages (gastrointestinal & respiratory tract) have special recognition receptors that allow them to recognize invaders they are called__________?
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Toll-like receptors (TLRs)
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Their are ________ types of TLRs and once activated TLR triggers the release of inflammatory chemicals called_______.
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11 types, cytokines
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Name some of the other inflammatory chemicals
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kinins, prostaglandins and complements
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What accounts for 2 of the cardinal signs of inflammation.
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Vasodilation - redness & heat are both due to local hyperemia (congestion with blood) occurs when local arterioles dilate.
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What is opsonization and how does it help phagocytes? Give an example of a molecule that acts as an opsonin.
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Opsonization is the process of making pathogens more susceptible to phagocytosis by decorating their surface with molecules that phagocytes can bind. Antibodies and complements proteins are examples of molecules that act as opsonins.
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Natural killers (NK)
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1.Promote aposptosis (cell suicide) by directly attacking virus infected or canderous body cells; 2. Recognize general abnormalities rather than specific atigens; 3. DO NOT form memory cells
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Under what circumstances might NK cells kill our own cells?
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Our own cells are killed by NK cells when they have been infected by viruses or when they have become cancerous.
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Kinins
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1. A plasma protein 4. Promotes vasodilation 2. Induce chemotaxis of leukocytes and prompt neutrophils to release lysosomal enzymes. 3. Induce pain
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Name the 3 phases of Phagocyte mobilization in inflammation
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1. Leukocytosis 2. Margination 3. Diapedesis 4. Chemotaxis
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Leukocytosis
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Injured cells release chemicals called leukocytosis-inducing factors. Neurophils enter blood stream from red bone marrow.
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Margination
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Inflamed endothelial cells sprout CAMs (cell adhesion molecules). Phagocytes clinging to the inner walls (margins) of the capillaries and postcapillary venules.
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Prostaglanding
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1. A fatty acid molecule 2. Promotes vasodilation 3. Induce neutrophil chemotaxis 4 Induce pain
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Chemotaxis
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Neutrophils follow chemotatic agents and migrate up the gradient to the site injury. Neurophils collect at the site and devour any foreign material.
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What is the cellular order of phagocyte mobilization.
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neutrophils, monocytes. Monocytes become macrophages and replace the neutrophils. Macrophages are the final disposal cell debris as acute inflammation subsides.
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Diapendesis
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Neutrophils flatten and squeee out of capillaries
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Name the 2 types of antimicrobial proteins
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Interferons & complement proteins
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What is a virus?
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Nucleic acids surrounded by a protein envelope.
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Steps of interferon mechanism (antimicrobial protein - innate internal defense)
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Host Cell - infected by virus, makes interferon, killed 1. Virus nucleic acid (DNA or RNA) enters cell 2. Interferon gene switches on 3. Cell produces interferon molecules Host Cell 2 - 1. Binds interferon from cell 1 2. interferon induces synthesis of protective proteins 3. intereron binding stimulates cell to turn on genes for antiviral proteins. 5. Antiviral proteins block viral reproduction.
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How do antimicrobial proteins work?
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Enhance our innate defenses by attaching microorganisms directly or by hindering their ability to reproduce.
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interferons
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1. Proteins released by virus infected cells and certain lymphocytes 2. Act as chemical messengers to protect uninfected tissue cells from viral takeover.
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Complement activation
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1. Classic, Lectin & Alternative pathway converge at C3 2. C3 splits into two active pieces: C3a & C3b which inhance inflammation and act as opsonins. 3. C3 also activates other complement proteins that can form a membrane attack complex MAC
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Fever
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Systemic response initiated by pyrogens; high body temp inhibits microbes from multiplying and enhances body repair processes. Fever also causes the liver & spleen to sequester iron & zinc.
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Complement (antimicrobial protein - innate internal defense)
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A group of bloodborne proteins that when activated 1. lyse microorganisms 2. enhance phagocytosis by opsonization 3. intensify inflammatory and other immune responses
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When leukocytes and macrophages are exposed to foreign substances in the body, they release chemicals called _________.
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pyrogens
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Pyrogens act on what system of the body?
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body's thermostat - a cluster of neurons in the hypothalamus.
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White pulp of spleen
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Which of the following areas in a secondary lymphoid organ allows intimate contact between blood and the lymphocytes?
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deep in the cortex
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Where in the lymph node do the T cells first encounter antigens presented by dendritic cells?
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Peyer's patches
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Collections of lymphoid tissues, called MALT, are strategically placed throughout the respiratory, digestive, and genitourinary systems. Which one of these is located at the end of the small intestine?
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Thymus
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There is a decrease in our ability to fight infection as we age. Which lymphoid organ may have a role in this decline?
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innate external defenses
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Tears and mucus membranes would be a part of which defense system?
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innate internal defenses
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Phagocytotic cells such as macrophages identify a variety of enemies by recognizing markers unique to pathogens. They would be classified as which type of defense system?
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Plasma B cells
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What cells make antibodies?
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an antigenic determinant
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What is the name of the unique area (specific region) that a lymphocyte recognizes and binds to?
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humoral immunity involves antibodies that can be transferred from one person to another.
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What type of immunity can be transferred by bodily fluids from one person to another, thus conferring immunity to the recipient?
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cell-mediated immunity (cellular immunity) - Yes, cell-mediated immunity involves an intracellular pathogen such as a virus.
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If a virus attacks a cell, which type of immunity would be activated?
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Cytotoxic T cells - Yes, cytotoxic T cells attack cancer cells, since they are part of cell-mediated immunity.
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Cancer cells would be attacked by which of the following cells?
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Neutralization
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Which mechanism occurs when antibodies block specific sites on viruses or bacterial exotoxins?
