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LYMPHATIC SYSTEM, IMMUNE SYSTEM - Coggle Diagram

- - - - travel with superficial veins, travel deep with arteries, nutrients supplied from branching vasa vasorum
    - - can take up larger molecules that blood capillaries cannot ex. proteins
      - more permeable than blood capillaries via mininvalves
      - minivalves: edges of squamous cells that overlap each other, forming one-way valves
        
        when pressure in the interstitial space is lesser than the pressure in lymphatic capillaries, valves shut
        
        when pressure in the interstitial space is greater than pressure in lymphatic capillaries, valves open
      - lacteals: specialized capillaries that transports absorbed fat (chyle) from small intestine to the bloodstream
      - absent from bones, teeth, bone marrow, and CNS
      - anchored to structures in interstitial space via collagen filaments
    - - lymphatic ducts: lymph is delivered from trunks to ducts
        
        thoracic duct: receives lymph from rest of body; dumps lymph into junction of l. jugular & l. subclavian vein
        
        cisterna chyli: drains fatty lymph from abdominal organs, volume/pressure changes influence lymph flow
        
        right lymphatic duct: drains lymph from righer upper limb, right side of head & thorax; dumps lymph into junction of r. jugular & r. subclavian vein
      - l. & r. lumbar trunks
      - l. & r. bronchomediastinal trunks
      - l. & r. subclavian trunks
      - l. & r. jugular trunks
      - intestinal trunk
- - - - medulla: contain more mature t-cells
      - cortex: contain less mature t-cells
  - - - capsule: dense fibrous; underneath are subcapsular sinuses
      - outer cortex: contains follicles w germinal center with dividing b cells; where b-cells differentiate into plasma cells
        
        subcapsular sinuses: bag-like structures leading into a number of small sinuses; contain lymph that drain into lymph node from afferent lymphatic vessels
      - trabeculae: connective tissue strands that divide nodes into compartments; surrounded by trabecular sinuses that allow lymph to drain deep into cortex from subcapsular sinuses
      - medulla: consist of cord-- thin inward extensions--& medullary sinuses, where it drains into efferent lymphatic vessel; b & t cells can be found
        
        medullary cord: contain macrophages, b-cells, & plasma cells
        
        medullary sinuses: where lymph collects before exiting the lymph node
      - lymph sinuses: found in node; are large lymphatic capillaries spanned by crisscrossing reticular fibers
      - inner cortex: paracortex; deeper part houses t-cells in transit; abundant with dendritic cells
      - sentinel node: first lymph node that receives lymph drainage from a body area suspected of cancer
      - afferent vessels: lead into node
      - efferent vessels: leaving the node; there are less efferent vessels than afferent
      - hilum: indented region on the concave side of the node leading into the efferent vessels
    - - red pulp: cluster of macrophages where RBCs and pathogens are destroyed; recycles parts
        
        venous sinuses (sinusoids): 30% of red pulp; broad interconnected vascular spaces, lined with specialized endothelial cells that filter blood; join and drain into splenic vein
        
        endothelial cells: abnormal RBCs can't pass between cells and are removed by nearby macrophages; reticular fibers surround sinusoids that provide structural support
      - white pulp: small nodules of lymphatic tissue; where antibodies are make by b-cells; composed of lymphocytes suspended in reticular fibers
        
        central arterioles: formed from trabecular arteries, surrounded by PALS
        
        PALS: periarteriolar lymphoid sheath, cylindrical sheath of most mature t-cells
        
        splenic follicles: localized expansion of PALS, composed of b-cells, can displace the central arterioles (still composed of t-cells)
        
        germinal center: eosinophilic center of follicle, contains activated b-cells
        
        mantle zone: surrounds germinal center, more dense area composed of b-cells and macrophages
        
        1 more item...
      - capsule: dense layer of connective tissue, forms short extension into spleen called trabeculae
        
        trabeculae: surrounds trabecular arteries of the spleen that supply spleen with blood
    - - tonsils: ring of lymphoid tissue around entrance of pharynx; contain follicles w germinal centers
        
        lingual tonsils: collective term for collection of lymphoid follicles at base of tongue
        
        palatine tonsils: located on either side of posterior end of oral cavity
        
        pharyngeal tonsil: posterior wall of nasopharynx
        
        tonsillar crypts: trap/destroy bacteria, allow immune cells to build memory for pathogens
      - appendix: contain lymphoid tissue that destroy remaining bacteria before it can breach intestinal wall; a tubular offshoot from first part of large intestine
      - peyer's patches: clusters of lymphoid follicles found in distal portion of small intestine wall; destroy bacteria and generate memory lymphocytes; m cells sample antigens and transfer to patches
- - - - cd4 t cell: cluster of differentiation; become helper t cell; secretes cytokines that coordinate macrophages & b cells; see antigens on mhc ii
        
        cytokines: bind to receptors and trigger a response in a receiving cell
        
        IL-2: stimulates t & b cell proliferation, t reg development, and nk cell activation
        
        IL-4: promotes differentiation of helper cells; promotes b cell activation
        
        T reg cells: moderate immune response
        
        activation: antigen presenting & co-stimulation
        
        antigen-presentation: APC cell engulfs exogenous antigen & displays it on a class II MHC
        
        co-stimulation: cd4 t cells recognize antigen MHC complex. CD4 & t cell receptor bind to antigen complex
      - cd8 t cell: cluster of differentiation, become cytotoxic t cell; kill target cells; only kill cells that present specific antigen on mhc i molecule
        
        perforins: form pores in the cell membrane
        
        granzymes: enter said pores and activate enzymes that trigger apoptosis
    - - active immunity: b cells bind to antigens
        
        naturally acquired: infection; contact with pathogen
        
        artificially acquired vaccine
      - passive immunity
        
        naturally acquired: antibodies passed from mother to baby
        
        artificially acquired: injection of antibodies
      - don't require MCH and can bind to antigen directly
      - plasma cells: produce antibodies; circulate in plasma & float freely so its considered humoral immunity
        
        antibodies: proteins; inactivate and tag antigens
        
        complement fixation:
        
        precipitation: soluble molecules are cross-linked into large complexes that settle
        
        agglutination: antibodies bind to same determinant on more than one antigen; causes clumping use IgM
        
        neutralization: simplest but most important; occurs when antibodies block sites on viruses/toxic chemicals
        
        monoclonal antibody: bind to one type of antigen; produces by hybridomas (fusion of tumor and B cell)
    - - immunocompetance:
      - self-tolerance: self-reactive cells are eliminated in bone marrow
  - - - MHC II: found on APCs; come from exogenous antigens; recognized by help T cells; signal to CD4 cells
        
        exogenous: extracellular antigens that have been engulfed
      - MHC I: displays endogenous antigens; displayed on every cell except RBCs; crucial for CD8 activation
        
        endogenous antigen: protein synthesized inside cell; can be self-antigens or non-self antigen (abnormal proteins)
- - - - lysosome: enzyme in saliva & lacrimal fluid that destroys bacteria
  - - - granules fuse with phagosome to from phagolysosome. granules lower pH of phagolysosome, making it acidic & killing some pathogens
      - oxidative burst: cell produces reactive O2 species that desroy proteins & nucleic acids in phagolysosome
      - diapedesis: when neutrophils squeeze through walls of capillaries
    - - opsonization: pathogen coated with opsonins, accelerates phagocytosis
    - - induces apoptosis by releasing cytotoxic granules that by binding to phosolipids and creating pores
    - - four cardinal signs: redness, heat, swelling, pain; impairment of function
      - three stages: inflammatory chemical release, vasodilation & increased vascular permeability, phagocyte mobilization
        
        phagocyte mobilization: leukocytosis- release of neutrophils from bone marrow in response to leukocytosis-inducing factors. margination- phagocytes cling to inner walls of capillaries and postcapillary venules
      - fever: high body temp, leukocytes and macrophages exposed to pathogen release pyrogens that raise body temp
      - interleukin: cytokines
        
        interleukin 6: sends cytokines to liver to produce acute phaser proteins that act to opsonins
        
        interleukin 8: recruits & activates neutrophils
        
        interleukin 1: sends cytokines to brain to produce fever, reduced appetite and cause lethargy (conserves energy)
        
        interleukin 2 &12: activate nk cells
    - - interferons: alpha, beta, gamma; proteins released by virus-infected cells and lymphocytes; act as a chemical messenger to protect infected cells from takeover; mobilizes IS
        
        alpha & beta: activate nk cells
        
        gamma: secreted by lymphocyte and has widespread immune mobilizing effects
        (activated macrophages)
      - complement: bloodborne proteins that when activated, lyse microorganisms , enhance phagocytosis by opsonization, and intensify inflammatory response
    - - dendritic cells: most common APC because it is found in sites that are in contact w/ external antigens; move to lymph for antigen presentation
      - monocyte
      - macrophages
      - antigen presentation: dendritic cells present amino acid chains to t cells; connects innate IS to adaptive
        
        MHC: major histocompatibility complex; where antigen is displayed to t cell
        
        mhc i: short chains of amino acids based on proteins synthesized inside the cell
        
        mhc ii: found on APCs; bind to fragments of exogenous antigens and display them