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Lymphatic/Immune System Leslie Vargas-Gonzalez | Period 5 - Coggle Diagram

- - - - MALT
        
        Lymphoid tissues in mucous membrane throughout body
        
        protects from pathogens trying to enter body
        
        APPENDIX
        
        offshoot of fist part of the large intestine
        1) Destroy bacteria, preventing them from breaching intestinal wall
        2) Generate "memory" lymphocytes
        
        TONSILS
        
        form ring of lymphatic tissue around pharynx; appear as swellings of mucosa
        
        gather and remove pathogens in food or air
        
        PEYER"S PATCHES
        
        clusters of lymphoid follicles in wall of distal portion of small intestine
        1) Destroy bacteria, preventing them from breaching intestinal wall
        2) Generate "memory" lymphocytes
      - LYMPHOID TISSUE
        
        Houses and provides proliferation sites for lymphocytes
        
        offers surveillance vantage points for lymphocytes and macrophages as they filter through lymph
      - SPLEEN
        
        blood -rich organ about the size of a fist; located in left side of abdominal cavity
        
        site of lymphatic proliferation and immune surveillance and response
        
        cleanses blood of aged blood cells and platelets; macrophages remove debris
      - LYMPH NODES
        
        embedded deep in CN tissue in clusters along lymphatic vessels
        
        some are near inguinal, axillary, and cervical regions
        1) Cleansing the lymph: act as lymph "filters"
        2) Immune system activation: offers a place for lymphocytes to become activated and mount an attack against antigens
  - - - RED BONE MARROW
        
        in the medullary cavity of the bone
        
        functions as location where B cells mature
      - THYMUS
        
        bilobed lymphoid organ found in inferior neck
        
        functions as lymphoid organs where T cells mature
- - - - phagocytes and NK cells kill any antigen they see, no matter how many times it enters the body
  - - - Cytotoxic T cells target antigens they recognize and kill them with perforins/granzymes/apoptosis
      - Plasma cells secrete specific antibodies that bind to free antigens, marking them for destruction by innate or other adaptive mechanisms
  - - - Skin and mucous membranes produce protective chemicals that inhibit/destroy microorganisms
      - surface barriers are skin and mucous membranes, along with their secretions
      - cilia of upper respiratory tract sweep dust- and bacteria-laden mucus toward mouth
      - mucus-coated hairs in nose trap inhaled particles
- - - - B lymphocytes ⇾ humoral immunity
        
        T lymphocytes ⇾ cellular immunity
    - - Dendritic cells
        
        act as moblie sentinels of boundary tissues -
        phagocytize pathogens that enter tissues, then enter lymphatics to present antigens to T cells in lymph node
      - Macrophages
        
        present antigens to T cells, which not only activates T cell, but also further activates macrophage
        
        activated macrophage becomes phagocytic killer
        
        triggers powerful inflammatory response and recruit additional defenses
      - engulf antigens and present fragments of antigens to T cells for recognitioj
      - B lymphocytes
        
        present antigens to helper T cell to assist their own activation
    - - Coded by genes of major histocompatibility complex
        
        contain groove that can hold piece of self-antigen or foreign complex
  - - - Phagocytes
        
        WBCs that ingest and digest foreign invaders
        Phagocytosis: engulf and digest pathogens
        
        Neutrophils: most abundant phagocytes, but die fighting; become phagocytic on exposure to infectious material
        
        Macrophages: develop from monocytes and ae cheif phagocytic cells; most robust phagocytic cell
      - Natural Killer Cells
        
        nonphagocytic, large granular lymphocytes that police blood and lymph
        
        can kill cancer and virus-infected cells before adaptive immune system is activated
        
        attack cells that lack "self" cell-surface receptors; apoptosis
      - Inflammation
        
        Step Three: Phagocyte Mobilization
        
        neutrophils flood area first; macrophages follow
        
        Step One: Imflammatpry Chemical Release
        
        chemicals are released into ECF by injured tissues or immune cells
        
        Step Two: Vasodilation and Increased Vascular Permeability
    - - SKIN & MUCOUS MEMBRANES
        
        Acid: acidity of skin and same mucous secretions inhibits growth; called acid mantele
        
        Mucin: sticky mucus that lines digestive and respiratory tract traps microorganisms
        
        Enzymes: lysosome of saliva, respiratory musucs, and lacrimal fluid kills many microorganisms; enzymes in stomach kill many microorganisms
- - - - Immunological Memory
        
        Primary Immune Response
        
        Cell proliferation and differentiation upon exposure to antigen for the first time
        
        lag period: 3~6 days | peak levels of plasma antibody are reached in 10 days
        
        Secondary Immune Response
        
        Re-exposure to same antigen gives faster, more prolonged, more effective response
        
        sensitized memory cell provide immunological memory
        
        antibodies bind with greater affinity
        
        respond within hours | peak in 2~3 days at much higher levels
      - Activation & Differentiation of B Cells
        
        B cells are activated when antigens bind to surface receptors
        
        triggers receptor-mediated endocytosis of cross-linked antigen-receptor
        
        most clone cells become plasma cells, antibody-secreting effector cells
        
        antibodies circulate in blood or lymph, binding to free antigens marking them for destruction by innate/adaptive mechanisms
        
        clone cells that do not become plasma cells become memory B cells
        
        provide immunological memory
        
        mount an immediate response to future exposures to same antigen
  - - - CD4 Cells
        
        usually become Helper T cells that can activate B cells, other T cells, and macrophage
        
        also become regulatory T cells & memory T cells
      - CD8 Cells
        
        become cytotoxic T cells that are capable of destroying cells harboring foreign antigens
    - - T cells respond only to processed fragments of antigens displayed on surfaces of cells by major histocompatibility complex (MHC) proteins
        
        Antigen presentation is vital for activation of naive T cells and normal functioning of effector T cells
    - - Co-stimulation
        
        Complete T cell activation requires T cell to also bind to one or more co-stimulatory signals on surface of APC
        
        both occur on surface of same APC & are required for clonal selection of T cell
      - Proliferation & Differentiation
        
        T cells that are activated enlarge and proliferates in response to cytokines
        
        Primary T cell response peak within a week
        
        T cell apoptosis occurs between days 7 and 10
        
        activated T cells are a hazard because they produce large amounts of inflammatory cytokines
      - Antigen Binding
        
        T cell antigen receptors bind to antigen-MHC complex on APC surface
        
        TCR must recognize both MHC and foreign antigen it displays
    - - Chemical messengers of immune system
        
        mediate cell development, differentiation, and responses in immune system
        
        includes interferons and interleukin
        
        interleukin 1 (IL-1) is released by macrophages ans stimulates T cells to:
        
        release interleukin 2 (IL-2)
        
        synthesize more IL-2 receptors
        
        IL-2 is a key growth factor, acting on same celss that release it and other T cells
    - - Cytotoxic T cells
        
        directly attack and kill other cells; circulate in blood and lymph and lymphoid organs in search of body cells displaying antigen they recognize
        Target: virus-infected cells | cancer cells | cells with intracellular bacteria or parasites | foreign cells
      - Helper T cells
        
        activate both humoral and cellular arms
        
        help activated B cells and other T cells
        
        induce T and cell proliferation
        
        secretes cytokines that recruit other immune cells
        without Helper T cells, there is NO immune response
- - - - targets of all adaptive immune responses
      - most are large, complex molecules not normally found in body
    - - contain antigenic determinants
      - can be a complete antigen or hapten
      - can be a self-antigen
  - - - overall T- or Y-shaped antibody monomer consists of four looping ploypeptide chains linked by disulfide bonds
        
        two identical heavy chains with hinge region at "middles"
        
        two identical light chains
        
        variable regions at one end of each arm combine to form two identical antigen-binding sites
        
        stems make up constant regions
    - - antibodies do not destroy antigens; they inactivate and tag them
        
        form antigen-antibody (immune) complexes
- - - - Naturally acquired: formed in response to actual bacterial or viral infection
      - Artifically acquired: formed in response to vaccine of dead or attenuated pathogens
  - - - Artifically acquired: injection of serum; such as gamma globulin
        
        protection immediate but ends when antibodies naturally defrade in body
      - Naturally acquired: anitbodies delievered to fetus via placenta or infant through milk
- - - - B Cells (APCs)
        
        produce plasma cells
        
        present antigens to helper T cell to assist their own activation
        
        Plasma Cells
        
        Secretes antibodies, which mark antigens for destruction by phagocytosis
        
        Memory B Cells
        
        Mount an immediate response to future exposures to same antigen
      - T Cells
        
        manage immune response and attack/destroy infected cells
        
        CD4+ CELL
        
        Regulatory T cells: helps prevent autoimmunity
        
        Memory T cells: Mount an immediate response to future exposures to same antigen
        
        Helper T cells: can activate B cells, T cells, and macrophages; secrete cytokines that recruit other cells
        
        NO HELPER T CELL = NO IMMUNE RESPONSE
        
        CD8+ CELL
        
        Cytotoxic T cells:directly attack and kill other cells; circulate in blood and lymph and lymphoid organs in search of body cells displaying antigen they recognize
        
        1) Tc cell releases perforins and granzymes by exocytosis
        2) Tc cell binds a specific membrane receptor on target cell and stimulates apoptosis
  - - - Stroma: network-like support that acts as scaffolding for immune cells
  - - - turn into macrophages once activated
    - - nonphagocytic; involved in allergic reactions - known for fighting helminthic parasites
        
        make holes in outer layet of helminths
    - - nonphagocytic; initiate allergic reactions
    - - live in tissues; nonphagocytic; causes inflammation in allergic responses
  - - - Phagocytize foreign substances and help activate T cells
        
        present antigens to T cells, which only only activates T cell, but also further activates mactophages
    - - Most abundant phagocytes, but die fighting; become phagocytic on exposure to infectious material
- - - - Type 1 Diabetes Mellitus: destroys pancreatic cells
        Systemic lupus erythematosus (SLE): affects multiple organs
        Glomerulonephritis: damages kidney
  - - - Hodgkin's Disease
        
        an acquired immunodeficiency that causes cancer of B cells, which depressed lymph node cells and thus leads to immunodeficiency
        
        Acquired Immune Deficiency Syndrome (AIDS)
        
        through human immunodeficiency virus (HIV) cripple immune system by interfering with activity of helper T cells; depressing cellular immunity
        
        HIV is transmitted via body fluids: blood semen, and vaginal secretions