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Chapter 21b
| Question | Answer |
|---|---|
| Body defenses function | provide resistance to fight infection, illness and disease |
| Two categories of defenses | - Innate (nonspecific) defenses - Adaptive (specific) defenses |
| Innate (Nonspecific) Defenses (3) | - Always work the same way - Against any type of invading agent - Nonspecific resistance |
| Adaptive (Specific) Defenses (3) | - Protect against specific pathogens - Depend on activites of lymphocytes - Specific Resistance (immunity) |
| Specific Resistance (immunity) | Develops after exposure to enviromental hazards |
| Seven Major Categories of Innate (Nonspecific) Defenses | 1) Barriers 2) Phagocytes 3) Immunological surveillance 4) Interferons 5) Complement 6) Inflammatory response 7) Fever |
| Barriers (2) | - Physical - Chemical |
| 1st line of innate defenses | Barriers |
| 2nd line of innate defenses (6) | - Phagocytes - Immunological surveillance - Interferons - Complement - Inflammatory Response - Fever |
| Physical Barriers (3) | - Outer layer of skin - Hair - Epithelial layers of internal passageways |
| Chemical Barriers (2) | - Secretions that flush away materials - Secretions that kill or inhibit microorganisms |
| Secretions that flush away materials (3) | - Sweat glands - Mucus - Urine |
| Secretions that kill or inhibit microorganisms (3) | - Enzymes - Antibodies - Stomach acid |
| Two Classes of Phagocytes | - Microphages - Macrophages |
| Microphages (3) | - Neutrophils and eosinophils - Leave the bloodstream - Enter peripheral tissues to fight infections |
| Macrophages (3) | - Large phagocytic cells derived from monocytes - Distributed throughout body - Make up monocyte–macrophage system (reticuloendothelial system) |
| Activated Macrophages respond to pathogens in several ways: (3) | - Engluf pathogen and destroy it with lysosomal enzymes - Bind to pathogen so other cells can destroy it - Destroy pathogen by releasing toxic chemicals into interstitial fluid |
| Two Types of Macrophages | - Fixed macrophages - Free macrophages |
| Fixed macrophages (2) | - Also called histiocytes - Stay in specific tissues or organs like dermis and bone marrow |
| Free macrophages (2) | - Also called wandering macrophages - Travel throughout body |
| Movement of macrophages (2) | - Move through capillary walls (emigration) - Are attracted or repelled by chemicals in surrounding fluids (chemotaxis) |
| Phagocytosis of macrophages begins | When phagocyte attaches to target (adhesion) and surrounds it with a vesicle |
| Immunological Surveillance (2) | - Carried out by natural killer (NK) cells - Activated NK cells |
| Activated NK cells (4) | 1. Identify and attach to abnormal cell (nonselective) 2. Golgi apparatus in NK cell forms perforin vesicles 3. Vesicles release proteins called perforins (exocytosis) 4. Perforins lyse abnormal plasma membrane |
| How NK cells kill cellular targets (4) | 1. Recognition and adhesion 2. Realignment of golgi apparatus 3. Secretion of perforin 4. Lysis of abnormal cell |
| Interferons | Proteins (cytokines) released by activated lymphocytes and macrophages |
| Cytokines | Chemical messengers released by tissue cells |
| Cytokines function (2) | - To coordinate local activities - To act as hormones to affect whole body |
| Three Types of Interferons | - Alpha-interferons - Beta interferons - Gamma-interferons |
| Alpha-interferons (2) | - Produced by leukocytes - Stimulate NK cells |
| Beta interferons (2) | - Secreted by fibrocytes - Slow inflammation |
| Gamma-interferons (2) | - Secreted by T cells and NK cells - Stimualte macrophage activity |
| Complement | Plasma contains (at least) 11 special complement (C) proteins |
| Complement activation (2) | - Complements work together in cascades - Three Pathways |
| What three pathways activate the complement system | 1. Classical Pathway 2. Lectin Pathway 3. Alternative Pathway |
| Complement | Plasma contains (at least) 11 special complement (C) proteins |
| Complement activation (2) | - Complements work together in cascades - Three Pathways |
| Effects of Complement Activation (3) | - Pore Formation - Enhancement of phagocytosis of opsonization - Histamine release from mast cells and basophils |
| What three pathways activate the complement system | 1. Classical Pathway 2. Lectin Pathway 3. Alternative Pathway |
| Effects of Complement Activation (3) | - Pore Formation - Enhancement of phagocytosis of opsonization - Histamine release from mast cells and basophils |
| Enhancement of phagocytosis by opsonization (2) | - C3b - Complements working with antibodies (opsonins) |
| Pore formation (2) | - Destruction of target plasma membranes - Membrane attack complex (MAC)- C5b-C9 |
| Inflammation (3) | - Also called inflammatory response - A localized response - Triggered by any stimulus that kills cells or injures tissue |
| Enhancement of phagocytosis by opsonization (2) | - C3b - Complements working with antibodies (opsonins) |
| Inflmmation signs and symptoms (5) | - Swelling (tumor) - Redness (rubor) - Heat (calor) - Pain (dolor) - Loss of function (Functio Laesa ) |
| Histamine release from mast cells and basophils (2) | - C3a and C5a (anaphylatoxins) - Increases inflammation and blood flow |
| Three Effects of Inflammation | 1. Temporary repair and barrier against pathogens 2. Retards spread of pathogens into surrounding areas 3. Mobilization of local and systemic defenses and facilitation of repairs (regeneration) |
| Inflammation (3) | - Also called inflammatory response - A localized response - Triggered by any stimulus that kills cells or injures tissue |
| Products of Inflammation (3) | - Necrosis - Pus - Abscess |
| Inflmmation signs and symptoms (5) | - Swelling (tumor) - Redness (rubor) - Heat (calor) - Pain (dolor) - Loss of function (Functio Laesa ) |
| Three Effects of Inflammation | 1. Temporary repair and barrier against pathogens 2. Retards spread of pathogens into surrounding areas 3. Mobilization of local and systemic defenses and facilitation of repairs (regeneration) |
| Products of Inflammation (3) | - Necrosis - Pus - Abscess |
| Necrosis | Local tissue destruction in area of injury |
| Pus | Mixture of debris and necrotic tissue |
| Abscess | Pus accumulated in an enclosed space |
| Fever (3) | - A maintained body temperature above 37C (99F) - Pyrogens - Endogenous pyrogens or interleukin-1 (IL-1) |
| Pyrogens (2) | - Any material that causes the hypothalamus to raise body temperature - Circulating pathogens, toxins, or antibody complexes |
| Endogenous pyrogens or interleukin-1 (IL-1) (2) | - Pyrogen released by active macrophages - A cytokine |
| Function of physical barriers | keep hazardous organisms and materials outside the body |
| Function of phagocytes | engulf pathogens and cell debris |
| Function of immunological surveillance | the destruction of abnormal cells by NK cells in peripheral tissues. |
| Function of interferons | chemical messengers that coordinate the defenses against viral infections |
| Function of complement system | consists of circulating proteins that assist antibodies in the destruction of pathogens |
| Function of inflammatory response | a localized, tissue-level response that tends to limit the spread of an injury or infection |
| Function of fever | an elevation of body temperature that accelerates tissue metabolism and the activity of defenses. |
| Adaptive (Specific) Defenses (3) | - Specific resistance (immunity) - Responds to specific antigens - With coordinated action of T cells and B cells |
| Specific Defenses (2) | - T cells - B cells |
| T cells (2) | - Provide cell-mediated immunity - Defend against abnormal cells and pathogens inside cells |
| B cells (2) | - Provide antibody-mediated immunity - Defend against antigens and pathogens in body fluids |
| Four Major Types of T Cells | 1. Cytotoxic T cells (Tc cells) 2. Memory T cells 3. Helper T cells (Th cells) 4. Suppressor T cells (Ts cells) |
| Cytotoxic T cells (also called TC cells) (2) | - Attack cells infected by viruses - Responsible for cell-mediated immunity |
| Memory T cells (4) | - Clone more of themselves in response to “remembered” antigen - produced with cytotoxic T cells - stay in circulation - immediately form cytotoxic T cells if same antigen appears again |
| Helper T cells (also called TH cells) | Stimulate function of T cells and B cells |
| Suppressor T cells (also called TS cells) (4) | - Inhibit function of T cells and B cells - Secrete Suppression factors - act after initial immune response - limit immune reaction to single stimulus |
| Antigen Presentation | T cells only recognize antigens that are bound to glycoproteins in plasma membranes |
| MHC Proteins (2) | - The membrane glycoproteins that bind to antigens - Genetically coded in chromosome 6 |
| The major histocompatibility complex (MHC) (2) | - Class I - Class II |
| Class I MHC Proteins (4) | - Found in membranes of all nucleated cells - Pick up small endogenous peptides (normal/abnormal) in cell and carry them to the surface - T cells ignore normal peptides - Abnormal peptides or viral proteins activate T cellss to destroy cell |
| Class II MHC Proteins (6) | - Found in membranes of antigen-presenting cells (APCs) - Class II MHC Proteins - Antigenic Fragments (exogenous) - From antigenic processing of pathogens - Bind to Class II proteins - Inserted in plasma membrane to stimulate T cells |
| Antigen-Presenting Cells (APCs) | Responsible for activating T cells against foreign cells and proteins |
| Phagocytic APCs (3) | - Free and fixed macrophages - Kupffer cells - Microglia |
| Free and Fixed macrophages location | in connective tissue |
| Kupffer cells location | of the liver |
| Microglia lcoation | In the CNS |
| Non-phagocytic APCs (2) | - Langerhans cells - Dendritic cells |
| Langerhans cells location | in the skin |
| Dendritic cells location | in lymph nodes and spleen |
| CD markers (4) | - Also called cluster of differentiation markers - In T cell membranes - Molecular mechanism of antigen recognition - More than 70 types |
| CD3 Receptor Complex (3) | - Found in all T cells - TCR with alpha and beta chains - Polypeptide chains; epsilon (ε), gamma (γ), delta (δ) and zeta (ζ) |
| Two Important CD Markers | - CD8 Markers - CD4 Markers |
| CD8 MArkers (2) | - Found on cytotoxic T cells and suppressor T cells - Respond to antigens on Class I MHC proteins |
| CD4 Markers (2) | - Found on helper T cells - Respond to antigens on CLass II MHC proteins |
| CD8 or CD4 Markers (2) | - Bound to CD3 receptor complex - Prepare cell for activation |
| T Cell / B Cell Activation – General Steps (5) | 1. Binding-Recognition 2. Anchoring 3. Co-stimulation 4. Proliferation 5. Differentiation |
| Binding recognition in T cell/B cell activation | appropriate receptor antigen pairing |
| Anchoring in T cell/B cell activation | appropritate MHC-CD pairing |
| Co-stimuation in T cell/B cell activation (3) | physical or chemical |
| Proliferation in T cell/B cell activation | clone any formation |
| Differentiation in T cell/B cell activation (2) | - activate T cell / B cell - memory cells |
| Activation of CD4 T cells (2) | - Active helper T cells (TH cells) - secrete cytokines - Memory helper (TH) cells - remains in reserve |
| Four Functions of Cytokines | 1. Stimulate T cell divisions 2. Attract and stimualte macrophages 3. Attract and stimualte activity of cytotoxic T cells 4. Promote activation of B cells |
| Activation of CD8 T Cells (3) | - Activated by exposure to antigens on NHC proteins - One responds wuickly which produces cytotoxic T cells and memory T cells - The other responds slowly which produces suppressor T cells |
| Cytotoxic T cells fucntion and steps (4) | - Seek out and immediately destroy target cells 1. Release. perforin 2. Secrete poisonous lymphotoxin 3. Activate genes in target cell |
| Why does cytotoxic T cells release perforin | To destroy antigenic plasma membrane |
| Why does cytotoxic T cells secrete poisonous lymphotoxin | To destroy target cell |
| What happens when cytotoxic T cells activate genes in target cell | causes cell to die |
| B cells (3) | - Responsible for antibody-mediated immunity - Attack antigens by producing specific antibodies - Millions of populations, each with different antibody molecules |
| B Cell Sensitization (3) | - Corresponding antigens in interstitial fluids bind to B cell receptors - B cell prepares for activation - Preparation process is sensitization |
| During Sensitization, antigens are (3) | - taken into the B cell - processed - reappear on surface, bound to Class II MHC protein |
| For T cell to be activated, it must be... (3) | - Costimulated which confirms the first signal - physically by binding to stimualting cell at second site (B7 on APC to CD28 on T cell) - Chemically via interleukins (IL 1 and 2) |
| Helper T cells for activation of B cells | Sensitized B cell is prepared for activation but needs helper T cell activated by same antigen |
| Binding recognition in B celll activation | helper T cells binds to antigen |
| Anchoring in B celll activation | MHC II of B cell attached to CD4 of helper |
| Costimulation in B celll activation | Helper cell secretes cytokines (iL 2) for B cell activation |
| Differentiation in B celll activation | Plasma cells and memory B cells |
| Plasma cells | synthesize and secrete antbodies into interstitial fluid |
| Memory B cells | Like memory T cells, remain in reserve to respond to next infection |
| Antibody structure (3) | Two parallel pairs of polypeptide chains held by disulfide bonds - One pair of heavy chains - One pair of light chains |
| in antibody structure, each chain contains (2) | - Constant segments - Variable segments |
| Five Heavy-Chain Constant Segments | 1. IgG 2.IgE 3. IgD 4.IgM 5. IgA |
| Variable Segments of Light and Heavy Chains | Determine specificity of antibody molecule |
| Antigen binding site (2) | - Free tips of two variable segments - Form antigen binding sites of antibody molecule which bind to antigenic determinant sites of antigen molecule |
| Antigen–Antibody Complex (3) | - An antibody bound to an antigen - Complete antigen - B cell sensitization |
| Compelte antigen | - immunogenicity : elect an immune response - reactivity : interacts with antibodies |
| B cell sensitization in antigen-antibody complex (3) | Exposure to a complete antigen leads to: - B cell sensitization - immune response |
| Hapten (Partial Antigens) | Must attach to a carrier molecule to act as a complete antigen |
| Dangers of Haptens | - Antibodies produced will attack both hapten and carrier molecule - If carrier is "normal" , antibody attacks normal cells |
| Immunoglobulins (Igs) (3) | - found in body fluids - determined by constant segments - have no effect on antibody specificity |
| Seven Functions of Antigen–Antibody Complexes | 1. Neutralization of antigen binding sites 2. Precipitation and agglutination 3. Activation of complement 4. Attraction of phagocytes 5. Opsonization 6. Stimulation of inflammation 7. Prevention of bacterial and viral adhesion |
| Precipitation and agglutination in Antigen-antibody complexes | formation of immune complex |
| Primary and Secondary Responses to Antigen Exposure (3) | - Occur in both cell-mediated and antibody-mediated immunity - first exposure: produces initial primary response - next exposure: triggers secondary response, more extensive and memory cells already primed |
| Forms of immunity (2) | - active - passive |
| active immunity and types (3) | - Antibodies develop after exposure to antigen - Naturally acquired - Artifically induced |
| passive immunity and types (3) | - Antibodies are transferred from another source - Naturally acquired - Artifically induced |
| Naturally acquired active immunity | through environmental exposure to pathogens |
| Artificially induced active immunity | Through vaccines containing pathogens |
| Naturally acquired passive immmunity | Antibodies acquired from the mother |
| Artificially induced passive immunity | By an injection of antibodies |
| IgG | Genral protection and placenta |
| IgE | for allergy |
| IgD | for B cell development |
| IgM | for massive/first response |
| IgA | for airways and secretions |
Created by:
JessicaKim1230