Lymph originates as blood plasma lost from the circulatory system, which leaks out into the surrounding tissues. The lymphatic system collects this fluid by diffusion into lymph capillaries, and returns it to the circulatory system. Once within the lymphatic system the fluid is called lymph, and has almost the same composition as the original interstitial fluid. The human lymphatic system Lymphatic circulation The lymphatic system acts as a secondary circulatory system, except it col ...
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