lymphatic system

• innate - non specific, wide variety of effector mechanism
• adaptive - specific, lymphocytes and antigen-presenting cells (APC)
• functions: site of active production lymphocytes
• primary lymphoid organs: thymus, bone marrow
• secondary lymphoid organs: lymph nodes, spleen, diffuse lymphoid tissue
• lymphatic tissues - lymphoid or lymphatic tissues. found in the mucosa of respiratory tract and digestive tract
• antigenic determinants - responsible for the specificity of the antigen-antibody reaction
• immune response - defensive reaction of cells
• lymphocytes:

  • predominant type of cells
  • small spherical or oval cells
  • large rounded nucleus, or slightly indented on one side
  • narrow, non granular
• b cell lymphocyte: humoral immunity and immunologi memory
• humoral immunity: responsible for specific immunoglobulin and antibody production
• immunologic memory: small lymphocytes serve as memory cells, secondary response
• t lymphocytes: helper t cell, cytotoxic t cell, regulatory t cell
• helper t cell:

  • CD4
  • produce cytokines
  • promote B cell to become plasma cell
  • activate macrophage
  • activate cytotoxic t lymphocytes
  • induces inflammatory reactions
• Antigenic Determinants - responsible for the specificity of the

  antigen-antibody reaction
• • Immune response - a specific defensive reaction of cells of the

  immune system against macromolecules
• IgG-

  • monomer
  • fetal circulation in pregnant women
  • activates phagocytosis, neutralizes antigens
• IgM

  • B lymphocyte surface (as a monomer)
  • first antibody produced in initial immune response; activates complement
• IgA

  • dimer with J chain and secretory component
  • secretions (saliva, milk, tears, etc.)
  • protects mucosae
• IgD

  • monomer
  • surface of b lymphocytes
  • antigen receptor triggering initial B cell activation
• IgE

  • monomer
  • bound to the surface of mast cells and basophils
  • destroys parasitic worms and participates in allergies
• T lymphocytes - attack invaders inside cells
• functions of t lymphocytes:

  • cell mediated immunity
  • graft rejection and tumor immunity
  • immunologic memory t cells
• b lymphocytes - differentiates into plasma cells
• Germinal center - central, pale staining portion of a

  lymphatic nodule
• thymus

  • fully formed and fully functional upon birth
  • remain large and very active in T cell production until puberty
  • decreases in size upon reaching adulthood
• IgM- fastest and largest
• IgG - long term
• IgA - secretions