RT Book, Section A1 Scoville, Steven A1 Caligiuri, Michael A. A2 Kaushansky, Kenneth A2 Prchal, Josef T. A2 Burns, Linda J. A2 Lichtman, Marshall A. A2 Levi, Marcel A2 Linch, David C. SR Print(0) ID 1178736112 T1 The Organization and Structure of Lymphoid Tissues T2 Williams Hematology, 10e YR 2021 FD 2021 PB McGraw-Hill Education PP New York, NY SN 9781260464122 LK hemonc.mhmedical.com/content.aspx?aid=1178736112 RD 2024/11/07 AB SUMMARYThe lymphoid tissues can be divided into primary and secondary lymphoid organs. Primary lymphoid tissues are sites where lymphocytes develop from progenitor cells into functional and mature lymphocytes. The major primary lymphoid tissue is the marrow, the site where all lymphocyte progenitor cells reside and initially differentiate. This organ is discussed in Chap. 4. The other primary lymphoid tissue is the thymus, the site where progenitor cells derived from the marrow differentiate into mature thymus-derived cells. Secondary lymphoid tissues are sites where lymphocytes undergo additional maturation and interact with each other and with nonlymphoid cells to generate immune responses to antigens. These tissues include the spleen, lymph nodes, and mucosa-associated lymphoid tissues such as tonsils. The structure of these tissues provides insight into how the immune system discriminates between self-antigens and foreign antigens and develops the capacity to orchestrate a variety of specific and nonspecific defenses against invading pathogens.