EXAM 4 CH.15,16,17 Terms in this set (232) What is the largest phagocyte that ingests and kills foreign cells Macrophages What is active in large eukaryotic infections like worms and fungi Eosinophils CD4 cells Helper T cells Produces and secrets ant

EXAM 4 CH.15,16,17 Terms in this set (232) What is the largest phagocyte that ingests and kills foreign cells Macrophages What is active in large eukaryotic infections like worms and fungi Eosinophils CD4 cells Helper T cells Produces and secrets antibodies in the primary response Plasma B cells Most common circulating WBC Neutrophils Second most common circulating WBC T lymphocytes B lymphocytes Produce and secret antibodies in the secondary response Mast cell Memory B cell Cells found in. the epidermis that assist in the first line of defense Dendritic cells Cells that throw "NETs" to trap pathogens. Neutrophils Releases histamines ( put 3 ) Mast cell Platelets Basophils Cells that act as professional antigens presenting cells ( put three) Dendritic cells B lymphocytes Macrophages Cells that kill by non-phagocytic means in the second line of defense ( put 3 ) Natural killer cells Eosinophils Neutrophils Cells that have elongated pseudopods for phagocytosis Dendritic cells Cells that have a cell surface receptor that is very similar to the structure of a basic antibody B lymphocytes Monocytes turn into this type of cell when they squeeze out of the capillary Macrophages CD8 cells Cytotoxic T cells Carry oxygen and carbon dioxide Erythrocyte Mature in the none marrow B lymphocytes Mature in the thymus gland T lymphocytes Red blood cells erythrocytes Causes apoptosis of host infected cells in cell-mediated immunity Cytotoxic cell Causes apoptosis of antibody labeled bacteria in humoral immunity Natural killer cell Active against cancers and virally infected cells in the second line of defense Natural killer cell HIV would lower the number of these types of cells Helper T cells Releases perforins & granzymes Natural killer cell Cytotoxic T cell Has a Co-Receptor that binds to the MHC I of the APC Cytotoxic T cell Has a Co-Receptor that binds to the MHC II of the APC Helper T cell Stimulate or activate both B cells and Cytotoxic T cells. Helper T cell Have a T cell receptor that will bind to the displayed epitope in an MHC II APC Helper T cell Have a T cell receptor that will bind to the displayed epitope in an MHC I APC Cytotoxic T cell Releases a substance similar to bleach in the second line of defense Neutrophiles What is hematopoiesis? What structures or organs take over? production of blood cells from undifferentiated stem cells; Yolk sac, liver and red bone marrow List the 4 signs of the inflammatory response. What does each sign mean? - Rubor : redness - Calor: warm - Tumor: swelling - Dolar: pain List the 6 steps of phagocytosis 1. Chemotaxis 2. Adherence 3. Ingestion to form phagosome 4. Merge with a lysosome to form a phagolysosome 5. Killing of pathogen 6. Elimination: exocytosis What are the three line of defense in the body? 1. Barriers like skin and mucous membranes prevent pathogen 2. Cells (phagocytes), chemicals (antimicrobials), and processes (inflammation, fever) respond when barriers are breached. 3. Adaptive immunity, producing specific antibodies against pathogens. What is species resistance and how does it protect organism ? refers to the natural ability of one species to resist pathogens that affect other species Define innate immunity is the body immediate non specific responses to pathogens How does species resistance and innate immunity differ? -Natural ability to resist certain pathogens due to incompatible structures and physiology (e.g., humans resistant to many plant and animal pathogens). -Nonspecific defenses present at birth, including physical barriers (skin, mucous membranes), and internal defenses (cells, chemicals, processes). What physical aspects of the skin help prevent the entry of pathogens? Epidermis: Multiple layers of tightly packed cells form a barrier. Dendritic Cells: Phagocytic cells in the skin that provide defense. Chemical Defenses: Dermal cells secrete antimicrobial peptides; sweat contains salt, antimicrobial peptides (dermcidins), and lysozyme, which inhibit and kill pathogens. What chemical aspects of the skin help prevent the entry of pathogens? Sweat & sebum Where are the mucous membrane located in the human body ? in the respiratory, digestive, urinary, and reproductive tracts How does mucous membranes provide physical protection against pathogens ? It contains chemical such as antimicrobial peptide and lysozyme. They are sticky and trap most microorganism What similarities between the skin and mucous membranes in terms of protection? tightly packed cells, contain defensins, they constantly shed and replace cells What are differences between the skin and mucous membranes in terms of protection? Skin has many layers while mucous only has a few Skin is dry mucous are moist Skin has sebum while mucous membranes do not Cilla is present in the trachea and uterine tube but not on skin What are dendritic cells and how do they function in the immune system? They are present antigens to cytotoxic T cells which are responsible for cell mediated immunity against infections How dendritic cells help combat infections? Intercept Invaders: Form a network in the epidermis to catch pathogens. Nonspecific Defense: Devour pathogens. Adaptive Immunity: Activate cytotoxic T cells (Tc cells) which kill infected cells via perforin-granzyme and CD95 pathways. Memory T Cells: Dendritic cells help form memory T cells for future responses. How do tears contribute to the bodys defense against infections ? They contain lysozyme an enzyme that destroys bacteria they act against peptidoglycan in bacteria cell walls What is a microbiome? the microorganisms in a particular environment (including the body or a part of the body). How does the microbiome help protect the body against diseases? through competitive inhibition by competing with potential pathogens. It stimulates the body's second line of defense What are antimicrobial peptides and how do they function in the immune system ? Also knows as defensins are found in the skin, mucous membranes and neutrophils How does the defensins combat pathogens? They punch holes in microbial membranes interrupting internal signaling enzyme or enzymatic actions acting as chemotactic factors forming fibers and nets to trap bacteria EXAM 4 CH.15,16,17 What antimicrobial substances are found in tears ? Lysozyme What are the main components of the body's first line of defense? Skin: Epidermis and dermis with dendritic cells, sweat (with lysozyme and defensins), and sebum (lowers pH). Mucous Membranes: Tightly packed cells, mucus from goblet cells. Tears and Saliva: Contain lysozyme; tears flush eyes, saliva protects teeth. Competitive Inhibition: Microbiome competes with pathogens; probiotics can help. Antimicrobial Peptides (Defensins): Act against pathogens on skin, mucous membranes, and in neutrophils. How do these blood components contribute to the body's defense ? Plasma: Contains proteins for inflammation and clotting to reduce blood loss and infection risk. Iron-binding Proteins: Sequester iron, making it unavailable to microorganisms. Leukocytes: White blood cells like macrophages, neutrophils, and dendritic cells engulf pathogens; eosinophils and NK cells attack nonphagocytically. Antimicrobial Chemicals: Include Toll-like receptors, NOD proteins, interferons, complement, lysozyme, and antimicrobial peptides. Chemotactic Factors: Chemokines attract phagocytic leukocytes to infection sites. Define chemotactic factors Chemical signals that attract other cells What role do chemotactic factors play in the immune response? Chemokines: Attract phagocytic leukocytes to infection sites. Positive Chemotaxis: Phagocytes move towards chemicals, using pseudopods to reach microorganisms. Function: Aid in adhesion, engulfing, and destroying pathogens through phagocytosis. How do the first and second lines of defense differ in their mechanisms of action? Cells: Phagocytes (macrophages, neutrophils, dendritic cells). Antimicrobial Chemicals: Toll-like receptors, NOD proteins, interferons, complement, lysozyme, antimicrobial peptides, chemokines. Processes: Phagocytosis, inflammation, fever. What are the different types of defensive blood cells? Basophils Eosinophils Neutrophils Lymphocytes Monocytes How does each type of blood cell contribute to fighting infections? Basophils: Release histamine during inflammation. Eosinophils: Phagocytize pathogens, especially helminths. Neutrophils: Phagocytize pathogens. Lymphocytes: Include NK cells, attack nonphagocytically. Monocytes: Become macrophages, which phagocytize pathogens. Why is lab analysis of leukocytes important in diagnosing infections? Differential White Blood Cell Count: Shows proportions of leukocyte types. Eosinophils Increase: Indicates allergies or parasitic infections. Neutrophils Increase: Common in bacterial infections. Lymphocytes Increase: Associated with viral infections. Abnormal Leukocyte Levels: Can indicate cancer or immunodeficiency. What can the levels and types of leukocytes indicate about a patient's health? Eosinophils Increase: Indicates allergies or parasitic infections. Neutrophils Increase: Common in bacterial infections. Lymphocytes Increase: Associated with viral infections. Abnormal Levels: Can suggest cancer or immunodeficiency. What are the six stages of phagocytosis? chemotaxis, adherence, ingestion, maturation, killing, elimination EXAM 4 CH.15,16,17 Describe each stage of phagocytosis in detail. Chemotaxis: Phagocyte attracted to infection site by chemical signals. Adherence: Phagocyte attaches to microbe. Ingestion: Phagocyte engulfs microbe, forming a phagosome. Maturation: Phagosome fuses with lysosome to form phagolysosome. Digestion: Microbe is broken down by enzymes. Exocytosis: Indigestible material is expelled. Define opsonization. attachment of c3b to bacteria to make them more susceptible to phagocytosis How does opsonization enhance the immune response? They make them more vulnerable to phagocytes How do eosinophils contribute to nonphagocytic killing of pathogens? They secrete anti microbial chemicals to attack large pathogens like parasitic helminths by adhering to their surface and releases toxins What is the role of NK cells in nonphagocytic killing? They secret toxins onto virally infected and cancer cells How do neutrophils participate in nonphagocytic killing of pathogens? By destroying microbes without phagocytosis What are Toll-like receptors? Protein receptors within cell membrane of macrophages How do Toll-like receptors function in the immune response? Function: Recognize pathogen-associated molecular patterns (PAMPs) on microbes. Response: Triggers inflammation, interferon release, adaptive immune responses, or apoptosis. Where are NOD proteins located in the cell? Intracellular, in the cell's cytoplasm. What role do NOD proteins play in the immune response? Recognize microbial components (PAMPs) and trigger inflammation, apoptosis, and other innate immune responses. What are interferons (IFNs)? Inhibit viral infections by triggering antiviral responses. How do interferons help combat viral infections? Type I (Alpha and Beta): Early response; act on infected and neighboring cells, producing antiviral proteins (AVPs) that degrade mRNA and inhibit protein synthesis. Type II (Gamma): Produced by T lymphocytes and NK cells; mainly activates macrophages and regulates the immune system What is the complement system? A set of serum proteins that act as opsonins and chemotactic factors, leading to inflammation and fever, and can destroy foreign cells How does the complement system function in the immune response? Classical Pathway: Activated by antibodies binding to antigens, leading to the activation of complement proteins. Alternative Pathway: Initiated directly by the presence of microbial surfaces and involves complement protein C3b. Lectin Pathway: Triggered when mannose-binding lectins recognize and bind to microbial surfaces. What is inflammation? localized tissue response to injury How does inflammation help fight infections? Increasing Blood Flow: Dilation of blood vessels brings more immune cells and nutrients to the infection site, aiding repair and response. Enhancing Immune Cell Activity: Leukocytes (white blood cells) move to the infection site, adhere to blood vessel walls, and then enter the tissue to engulf and destroy pathogens. Promoting Healing: The increased blood flow and immune cell activity help remove pathogens and damaged cells, leading to tissue repair. What is fever? Systemic response to invading microorganisms How does fever contribute to the body's Enhances Interferon Effects: Boosts the antiviral effects of interferons. Inhibits Microbial Growth: Many pathogens grow more slowly at higher temperatures. EXAM 4 CH.15,16,17 What are the five distinctive characteristics of adaptive immunity? Specificity: Targets specific antigens, not others. Inducibility: Activated by specific antigens on pathogens. Clonality: Proliferates into many identical cells, known as clones. Unresponsiveness to Self: Tolerance to self-antigens, though it can break down in autoimmune diseases. Memory: Remembers previous encounters for quicker and more effective responses. How do these characteristics differentiate adaptive immunity from other immune responses? Innate Immunity: Immediate, non-specific response using broad mechanisms like phagocytes and antimicrobial proteins; no memory. Adaptive Immunity: Delayed, specific response with the ability to remember and respond more effectively to previously encountered pathogens; involves B and T lymphocytes. What are the two basic types of white blood cells involved in adaptive immunity? B lymphocytes T lymphocytes What roles do these white blood cells play in adaptive immunity? B Lymphocytes (B Cells): Function: Responsible for producing antibodies that target extracellular pathogens and toxins. T Lymphocytes (T Cells): Function: Involved in cell-mediated immune responses, targeting intracellular pathogens such as viruses and some bacteria. They can directly kill infected cells or help other immune cells. How does adaptive immunity differ from innate immunity in terms of response mechanisms and specificity? Specificity: Adaptive Immunity: Targets specific antigens with tailored responses. Innate Immunity: Recognizes broad patterns shared by many pathogens. Response Mechanisms: Adaptive Immunity: Involves lymphocytes (B cells for antibody responses, T cells for cell-mediated responses). Innate Immunity: Utilizes various cells (phagocytes, natural killer cells) and proteins (complement). What are the main branches or divisions of adaptive immunity? Cell-Mediated Immune Responses: Controlled by T cells; targets intracellular pathogens (e.g., viruses inside cells). Humoral Immune Responses : Managed by B cells; involves antibodies that bind to specific antigens. How do these properties influence the strength and type of immune response? Biochemical Shape, Size, and Location: These determine the strength and type of immune response. Cell-Mediated Responses: Target intracellular pathogens and abnormal body cells (e.g., viruses inside cells). Antibody Responses: Target extracellular pathogens and toxins. What are exogenous antigens, and how do they enter the body? Antigens from outside the body's cells, such as toxins, microbial components (cell walls, membranes, flagella, pili), and substances from food or inhaled dust. What are endogenous antigens, and how are they generated within the body? Production: Pathogens inside cells produce endogenous antigens. Processing: Nucleated cells cut polypeptides into smaller pieces (epitopes) using proteases. Binding: These epitopes move into the endoplasmic reticulum (ER) and bind to MHC class I molecules. Transport: The ER packages MHC class I proteins with bound epitopes into vesicles. Display: The vesicles fuse with the cytoplasmic membrane, integrating their membrane with the cell's surface What are autoantigens, and how do they relate to autoimmune diseases? the body's own proteins or molecules that the immune system mistakenly identifies as foreign. EXAM 4 CH.15,16,17 Where are MHC class II proteins located, and what is their function? Found on the cytoplasmic membranes of professional antigen-presenting cells (APCs) such as macrophages, B cells, and dendritic cells. Hold and position epitopes for presentation to immune cells. MHC class II molecules display epitopes from exogenous antigens What are antigen-presenting cells (APC) and how do they function in the immune response They are specialized cell that capture, ingest, and degrade antigens into epitopes; then display these epitopes on their surface using MHC class II proteins. How do MHC molecules participate in the processing and presentation of antigens? by holding and positioning epitopes for presentation to immune cells What is endogenous antigen processing? Class I MHC binds to antigens that originate in the cytoplasm (inside) of the cell and present these antigens to T-cells How does the body process and present endogenous antigens? they processed within nucleated cells and presented by MHC Class I molecules, allowing immune cells to detect antigens inside the cell. What is exogenous antigen processing? Class II MHC binds to antigens that originate from outside the cell and present to T- cells How does the body process and present exogenous antigens? they are processed by APCs like dendritic cells and presented on MHC Class II molecules, allowing immune cells to detect external antigens. What role does the thymus play in the development and maturation of T lymphocytes? ensures T cells can recognize foreign antigens presented by MHC proteins while avoiding autoantigens, creating a repertoire of protective T cells. How does the thymus contribute to the immune response? by developing and maturing T lymphocytes (T cells)