Anatomy of the Lymphatic System and Its Disorders

Abstract

The lymphatic system is a bodily complex composed of interstitial space, body ­cavities, and lymphatics (all of which form the lymphatic space), containing tissue fluid and lymph, migrating immune cells, and organized lymphoid tissue (Fig. 5.1). The total mass comprising extracellular fluid, lymph and lymphoid cells is estimated to be 13 kg. The cell mass alone approximates 1 kg,1 Lymph nodes and lymphoid cell aggregates, identified as lamina propria and Peyer’s patches in the intestine, contain the main aggregates of the recirculating lymphocytes.The lymphoid organs (thymus, spleen and bone marrow) are contained within the blood system and have no lymphatic drainage; however, their cells circulate in the loop of blood–tissue–space–lymphatics–lymphoid tissue–blood. In this sense, they belong to the lymphatic system.2–4