#immune_system  a system (including the thymus and bone marrow and lymphoid tissues) that protects the body from foreign substances and pathogenic organisms by producing the immune response
  supertype:  system.body_part  a group of physiologically or anatomically related organs or parts; "the body has a system of organs for digestion"
  part:  bone_marrow__marrow  the fatty network of connective tissue that fills the cavities of bones
  part:  thymus_gland__thymus  a ductless glandular organ at the base of the neck that produces lymphocytes and aids in producing immunity; atrophies with age
  part:  lymph_node__lymphnode__lymph_gland__lymphgland__node  the source of lymph and lymphocytes
  part:  reticuloendothelial_system__reticuloendothelialsystem__RES  a widely distributed system consisting of all the cells able to ingest bacteria or colloidal particles etc, except for certain white blood cells
     part:  mononuclear_phagocyte_system__mononuclearphagocytesystem__MPS__system_of_macrophages  a widely distributed system of free and fixed macrophages derived from bone marrow

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