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organs of the lymphatic system in the higher vertebrates and man.
The lymph nodes are oval formations along the path of the lymphatic vessels that consist of reticular tissue enclosed in a connective-tissue capsule and in which lymphocytes are formed. The lymph flow in the narrow cavities (sinuses) of the nodes is retarded markedly, facilitating the capture by leukocytes (phagocytes) of foreign particles entering from the tissues through the lymphatic vessels and preventing their entry into the blood. Thus, the more lymph nodes (and their number increases in the progression from the lower mammals to man), the stronger the barrier protecting the body from pathogenic principles. In man, the dimensions of the lymph nodes vary from 3 mm to 30 mm. However, with certain diseases, these dimensions may increase sharply (for example, the otic nodes, in cases of epidemic parotitis or tonsillitides), sometimes even reaching the size of a hen’s egg.
V. B. SUKHANOV