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As development progresses, blood formation occurs in the spleen, liver and lymph nodes. When bone marrow develops, it eventually assumes the task of forming most of the blood cells for the entire organism. [3] However, maturation, activation, and some proliferation of lymphoid cells occurs in the spleen, thymus, and lymph nodes. In children ...
Lymphatic vessels carry lymph, a colorless, watery fluid originating from interstitial fluid (fluid in the tissues) which is squeezed out of the blood vessels. The lymphatic system transports infection-fighting cells called lymphocytes , is involved in the removal of foreign matter and cell debris by phagocytes and is part of the body's immune ...
The primary function of lymph nodes is the filtering of lymph to identify and fight infection. In order to do this, lymph nodes contain lymphocytes, a type of white blood cell, which includes B cells and T cells. These circulate through the bloodstream and enter and reside in lymph nodes. [24] B cells produce antibodies.
Diagram showing the development of different blood cells from haematopoietic stem cell to mature cells. Haematopoiesis (/ h ɪ ˌ m æ t ə p ɔɪ ˈ iː s ɪ s, ˌ h iː m ə t oʊ-, ˌ h ɛ m ə-/; [1] [2] from Ancient Greek αἷμα (haîma) 'blood' and ποιεῖν (poieîn) 'to make'; also hematopoiesis in American English, sometimes h(a)emopoiesis) is the formation of blood cellular ...
Myeloid neoplasms always concern bone marrow cell lineage and are related to hematopoietic cells. Myeloid tissue can also be present in the liver and spleen [ 5 ] in fetuses , and sometimes even in adults as well, which leads to extramedullary hematopoiesis .
These B cells then leave the bone marrow and migrate via bloodstream and the lymph to peripheral lymphoid tissues, such as a spleen, lymph nodes, tonsils and mucosal tissues. Once in a secondary lymphoid organ the B cell can be introduced to an antigen that it is able to recognize. [citation needed]
Lymph returns proteins and excess interstitial fluid to the bloodstream. Lymph also transports fats from the digestive system (beginning in the lacteals) to the blood via chylomicrons. Bacteria may enter the lymph channels and be transported to lymph nodes, where the bacteria are destroyed. Metastatic cancer cells can also be transported via lymph.
The lymph tissue in the lymph nodes consists of immune cells (95%), for example lymphocytes, and stromal cells (1% to 5%) [5] The genesis of lymph nodes begins within the blood and the lymphatic system. [4] Interactions between stromal and hematopoietic cells are important for the development of lymph nodes. Crosstalk LEC, lymphoid tissue ...