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Immune System - Anatomy & Physiology

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  • What are the three main lines of defense in the immune system?

    Barrier protection (physical, mechanical, chemical)

    Innate immune response (rapid, non-specific)

    Adaptive immune response (slow, specific, with memory)

  • What distinguishes 'self' from 'non-self' in immunity?

    Self refers to healthy, damaged, or infected cells of the body; non-self includes bacteria, viruses, parasites, and allergens.
  • What are the components of interstitial fluid relevant to immunity?

    Water, ions (Na+, Cl-, K+, Ca2+), dissolved gases (O2, CO2), sugars, amino acids, proteins, nitrogen waste, and immune cells like lymphocytes and macrophages.
  • What is the role of the lymphatic system in immunity?

    It redistributes interstitial fluid, transports white blood cells, and drains fluid from tissues into major veins near the heart.
  • What are the primary lymphoid tissues and their functions?

    Bone marrow produces all white blood cells and matures B cells; thymus gland is where T cells mature.
  • Name the secondary lymphoid tissues and their roles.

    Lymph nodes filter lymph and house immune cells; spleen stores white blood cells, controls blood cell levels, and filters old red blood cells.
  • What are the physical, mechanical, and chemical barriers in the immune system?

    Physical: skin and mucosa; Mechanical: mucous, coughing, sneezing; Chemical: stomach acid pH, lysozyme enzymes.
  • What characterizes the innate immune response?

    Rapid, non-specific defense involving phagocytes, complement proteins, natural killer cells, and inflammation without memory.
  • Describe the process of phagocytosis in innate immunity.

    Recognition of pathogen, engulfment by phagocyte, digestion in lysosomes, debris release, and signaling to immune system.
  • What are the main types of phagocytic white blood cells?

    Neutrophils (general phagocytes), monocytes/macrophages (engulf larger particles), and dendritic cells (antigen presentation).
  • What is antigen presentation and which cells perform it?

    Displaying pathogen fragments (epitopes) on MHC-II molecules to activate T cells; performed by dendritic cells, B cells, and macrophages.
  • How do natural killer (NK) cells identify and kill target cells?

    NK cells detect absence of MHC-I on target cells and use activating receptors to kill infected or cancerous cells via perforins and granzymes.
  • What is the complement system and its functions?

    A group of liver-produced proteins that promote inflammation, opsonization, and form membrane attack complexes to lyse pathogens.
  • Outline the steps of the inflammatory response.

    Mast cells release histamine causing capillary dilation; macrophages release cytokines recruiting WBCs; neutrophils phagocytose pathogens; platelets form clots.
  • What distinguishes adaptive immunity from innate immunity?

    Adaptive immunity is specific, slower to respond, has memory, and involves B cells (humoral) and T cells (cell-mediated).
  • What are the roles of B cells in adaptive immunity?

    B cells produce antibodies, differentiate into plasma cells (antibody producers), and memory B cells for long-term immunity.
  • How do T helper cells assist the immune response?

    They recognize antigens on MHC-II, activate, clone, and release cytokines to stimulate B cells and cytotoxic T cells.
  • Describe the function of cytotoxic (killer) T cells.

    They recognize infected cells presenting antigen on MHC-I and kill them by injecting proteases, granzymes, and perforins.
  • What is the difference between active and passive immunity?

    Active immunity is gained by own immune response (natural infection or vaccination); passive immunity is received from another source (maternal antibodies or treatments).
  • What is opsonization in the immune response?

    The process of labeling pathogens with molecules to enhance recognition and ingestion by phagocytes.