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Immune System - Anatomy & Physiology

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Terms in this set (31)

  • What are the three lines of defense in the immune system?
    First line: Surface barriers (skin, mucosa).
    Second line: Innate internal defenses (inflammation, phagocytes, NK cells).
    Third line: Adaptive defense system (lymphocytes, antibodies).
  • What are the main components of the first line of defense?
    Keratinized epidermis and protective chemicals such as acid, enzymes, mucin, and defensins.
  • Name two types of phagocytes and their characteristics.
    Neutrophils: Abundant, die fighting.
    Macrophages: Voracious, derived from monocytes.
  • List the steps of phagocytosis.
    1. Phagocyte binds particle.
    2. Particle enclosed in phagosome.
    3. Phagosome fuses with lysosome forming phagolysosome.
  • What is opsonization?
    Pathogens are coated with opsonins (complement proteins or antibodies) to enhance phagocytosis.
  • What role do Natural Killer (NK) cells play in immunity?
    NK cells kill cancer and virus-infected cells by inducing apoptosis.
  • What are the cardinal signs of inflammation?
    Redness, heat, swelling, and pain.
  • Describe the stages of inflammation.
    Chemical release (histamine), vasodilation, increased permeability, phagocyte mobilization (leukocytosis, margination, diapedesis, chemotaxis).
  • What is pus composed of?
    A mixture of dead neutrophils, tissue cells, and pathogens.
  • Name two types of antimicrobial proteins involved in innate immunity.
    Interferons (IFNs) and complement proteins.
  • What is the purpose of fever in immune response?
    A systemic response to infection that increases body temperature to inhibit pathogen growth.
  • What are the key features of adaptive immunity?
    Specificity, systemic action, and memory to target and eliminate pathogens and abnormal cells.
  • Differentiate between humoral and cellular immunity.
    Humoral immunity is antibody-mediated by B cells.
    Cellular immunity involves T cells acting directly or indirectly against target cells.
  • Define antigens.
    Substances that provoke an immune response and are not normally found in the body.
  • What are haptens?
    Incomplete antigens; small molecules that become immunogenic when combined with proteins.
  • What are antigenic determinants?
    Specific parts of an antigen that antibodies bind to.
  • What are self-antigens?
    MHC proteins that display self or foreign peptides to the immune system.
  • Which cells provide humoral immunity and which provide cellular immunity?
    B cells provide humoral immunity.
    T cells provide cellular immunity.
  • What is the role of antigen-presenting cells (APCs)?
    Dendritic cells, macrophages, and B cells present antigens to T cells to initiate adaptive immunity.
  • Where do B and T cells originate and mature?
    Both originate in red bone marrow.
    B cells mature in bone marrow; T cells mature in the thymus.
  • What is positive selection in T cell education?
    Ensures T cells recognize self MHC proteins.
  • What is negative selection in T cell education?
    Eliminates T cells that react to self antigens to prevent autoimmunity.
  • Describe the primary and secondary humoral immune responses.
    Primary: Lag period 3-6 days, peak antibody in 10 days.
    Secondary: Faster and stronger due to memory cells.
  • What is the difference between active and passive immunity?
    Active immunity involves B cells producing antibodies after antigen exposure.
    Passive immunity involves receiving ready-made antibodies.
  • What does the acronym PLAN stand for in antibody mechanisms?
    Precipitation, Lysis (via complement), Agglutination, Neutralization.
  • What are the main types of T cells and their functions?
    CD4 (helper and regulatory) and CD8 (cytotoxic) T cells.
  • What is required for T cell activation?
    Two-step process: antigen binding and co-stimulation.
  • What role do cytokines play in immunity?
    Chemical messengers that regulate immune responses.
  • What is the function of helper T cells?
    Activate B and T cells, secrete cytokines, and amplify innate defenses.
  • What is the role of cytotoxic T cells?
    Directly attack and kill infected or abnormal cells.
  • What do regulatory T cells do?
    Dampen immune response and prevent autoimmunity.