Illustration of a sectioned, whole human lymph node. Lymph nodes are encapsulated, kidney shaped structures that are usually located at intervals along lymph vessels. Functions include filtration" of lymph by scavenging macrophages, production & storage of both antibody-secreting B- lymphocytes involved in humoral immunity, and of T-lymphocytes involved in the cell-mediated immune response. A labyrinth of cells and cell processes in the inner medullary sinuses serves to slow the flow of fluid through the node & so encourage the actions of lymphatic cells involved in the immune response processes."