50 Questions
Which type of immunity is characterized by defenses against any pathogen?
Innate immunity
Which cells are NOT considered phagocytes?
T cells
Which protein found in the skin acts as a protective barrier against microbes?
Keratin
Which receptors attach to pathogen-associated molecular patterns (PAMPs) to induce cytokines?
Toll-like receptors (TLRs)
Which pathway(s) activate(s) the complement system?
Classical, alternative, and lectin
How do some bacteria evade complement?
Preventing membrane attack complex (MAC) formation and enzymatic digestion of C5a
What role do interferons (IFNs) play in antiviral defense?
Inhibiting viral replication and stimulating phagocytosis
What type of immunity involves transferrins and antimicrobial peptides?
Innate immunity
Where do T and B cells differentiate and develop?
Red bone marrow or thymus and lymphoid tissue
What are the characteristics of adaptive immunity?
Molecular specificity, immunological memory, and a stronger response upon re-exposure
What does cell-mediated immunity (CMI) involve?
T cells and deals with intracellular invaders
How do T cells recognize antigens?
Requiring antigen presentation by the body's own cells
What guides T cells in recognizing antigens?
CD markers
How many antigen-binding sites do B-cell receptors have?
Two identical antigen-binding sites
Which of the following is an example of a physical factor contributing to innate immune defense?
Lacrimal apparatus
Which of the following is a chemical factor involved in innate immune defense?
Lysozyme
What is the role of normal microbiota in the context of innate immunity?
Microbial antagonism
Which of the following is an essential part of the body's second line of defense?
Lymph nodes
What do sentinel cells use to identify unique microbial components?
Pattern recognition receptors
Which of the following plays a vital role in destroying invaders as part of innate effector actions?
Complement system
Which cells are responsible for innate immunity in the immune system?
Granulocytes
What does the differential white cell count show?
The percentage of each type of white cell in a sample of 100 white blood cells
What is the process performed by phagocytes involving the ingestion of microbes or particles?
Phagocytosis
Where are pattern recognition receptors found?
Cell surface, in endosomes and phagosomes, and free in the cytoplasm
What do pattern recognition receptors detect to indicate microbial invasion and cell damage?
Pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs)
What are the phases of phagocytosis?
Ingestion and destruction of pathogens
Which process involves the release of chemicals by damaged cells, blood clot formation, abscess formation, margination, diapedesis, and phagocytosis of invading bacteria?
Inflammation
What is the indicator of infection, caused by gram-negative endotoxins, and involves the hypothalamus, interleukin-1, prostaglandins, and increased rate of metabolism?
Fever
What is activated in a cascade, causing opsonization, cytolysis, and attraction of phagocytes?
The complement system
What causes bursting of the microbe due to the inflow of extracellular fluid through the transmembrane channel?
The membrane attack complex
What is the outcome of complement activation that includes opsonization, inflammation, attraction of phagocytes, and cytolysis through the formation of the membrane attack complex?
Complement activation
What involves inhibiting adherence, killing phagocytes, lysing phagocytes, escaping phagosome, preventing phagosome-lysosome fusion, and surviving in phagolysosome?
Microbial evasion of phagocytosis
What is the second line of defense involving activation of acute-phase proteins, vasodilation, redness, swelling, pain, heat, and release of chemicals like histamine, kinins, prostaglandins, and leukotrienes?
Inflammation
What involves the complement system, which is activated in a cascade, causing opsonization, cytolysis, and attraction of phagocytes?
The complement system
What is the process involving chemotaxis, adherence, ingestion, formation of phagosome, fusion with lysosome, digestion, and discharge of waste materials?
Phagocytosis
What is an indicator of infection, caused by gram-negative endotoxins, and involves the hypothalamus, interleukin-1, prostaglandins, and increased rate of metabolism?
Fever
What is the process involving the release of chemicals, blood clot formation, phagocyte migration, and phagocytosis, and tissue repair?
Inflammation
What involves the complement system, which can be activated through three pathways: classical, alternative, and lectin?
The complement system
What are the two processes that prevent inappropriate adaptive immune responses?
Central tolerance and peripheral tolerance
What is the function of memory lymphocytes in the adaptive immune system?
Provide a faster and more effective secondary response
Which cells are involved in the humoral immune system?
B cells
Where do T cells mature in the body?
Thymus
What are antigens?
Substances that cause the body to produce specific antibodies or sensitized T cells
Which class of immunoglobulins is involved in allergic reactions?
IgE
How are B cells activated to produce antibodies?
By major histocompatibility complex (MHC) and T-dependent or T-independent antigens
What is clonal selection and differentiation of B cells based on?
Selection of B cells bearing surface immunoglobulins against a specific antigen
How are B cells activated through cytokines produced by T helper cells?
Antigens presented on the surface of B cells with MHC class II
What is the dual nature of the adaptive immune system?
Humoral (antibody-mediated) and cellular (cell-mediated) immune system
What is the role of antibodies in the immune system?
Interact with antigenic determinants
What activates the cellular immune system to respond to intracellular pathogens?
T cells
Study Notes
Phagocytosis and Microbial Evasion Summary
- Phagocytosis is a multi-step process involving chemotaxis, adherence, ingestion, formation of phagosome, fusion with lysosome, digestion, and discharge of waste materials
- Microbial evasion of phagocytosis includes inhibiting adherence, killing phagocytes, lysing phagocytes, escaping phagosome, preventing phagosome-lysosome fusion, and surviving in phagolysosome
- Inflammation is the second line of defense involving activation of acute-phase proteins, vasodilation, redness, swelling, pain, heat, and release of chemicals like histamine, kinins, prostaglandins, and leukotrienes
- Phagocyte migration and phagocytosis involves the release of chemicals by damaged cells, blood clot formation, abscess formation, margination, diapedesis, and phagocytosis of invading bacteria
- Fever is an indicator of infection, caused by gram-negative endotoxins, and involves the hypothalamus, interleukin-1, prostaglandins, and increased rate of metabolism
- Antimicrobial substances include the complement system, which is activated in a cascade, causing opsonization, cytolysis, and attraction of phagocytes
- The complement system can be activated through three pathways: classical, alternative, and lectin
- Outcomes of complement activation include opsonization, inflammation, attraction of phagocytes, and cytolysis through the formation of the membrane attack complex
- Complement activation results in the release of histamine, inflammation, and the formation of the membrane attack complex leading to cytolysis
- The membrane attack complex causes bursting of the microbe due to the inflow of extracellular fluid through the transmembrane channel
- Inflammation is stimulated by complement, leading to various immune responses
- The process of inflammation involves the release of chemicals, blood clot formation, phagocyte migration, and phagocytosis, and tissue repair
Adaptive Immune Tolerance and Responses Overview
- Immune tolerance prevents inappropriate adaptive immune responses by two processes: central tolerance and peripheral tolerance.
- Naïve lymphocytes cannot react until they receive confirming signals, whereas activated lymphocytes proliferate and differentiate.
- Memory lymphocytes provide a faster and more effective secondary response to repeated encounters with the same antigen.
- The adaptive immune system has a dual nature: humoral (antibody-mediated) immune system and cellular (cell-mediated) immune system.
- The humoral immune system involves B cells that mature in the bone marrow and produce antibodies.
- The cellular immune system involves T cells that mature in the thymus and respond to intracellular pathogens.
- Antigens are substances that cause the body to produce specific antibodies or sensitized T cells, and antibodies interact with antigenic determinants.
- Antibodies are globular proteins called immunoglobulins with different classes like IgG, IgM, IgA, IgD, and IgE, each with specific functions.
- B cells are activated by major histocompatibility complex (MHC) and T-dependent or T-independent antigens to produce antibodies.
- Clonal selection and differentiation of B cells involve the selection of B cells bearing surface immunoglobulins against a specific antigen and clonal expansion.
- Antigens can be presented on the surface of B cells with MHC class II and activate the B cells through cytokines produced by T helper cells.
- The adaptive immune system's dual nature provides comprehensive protection against a wide range of pathogens and is essential for maintaining immune homeostasis in the body.
Test your knowledge of immune system defense mechanisms and adaptive immune responses with this comprehensive quiz. Explore topics such as phagocytosis, microbial evasion, inflammation, complement activation, immune tolerance, lymphocyte activation, and the dual nature of the adaptive immune system. Brush up on key concepts and challenge yourself with this informative quiz.
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