Lymphatic System in Gastro-Intestinal Tract

The lymphatic system is frequently studied for its connection with the disease process as it plays a vital role in both immune function, surplus extracellular fluid drainage, and transportation of dietary fats. The high permeability of these lymphatic vessels allows them to take up most macromolecules and immune cells. This provides a unilateral transport pathway for excess fluid and protein collected from the interstitial space to return to circulation. Our small intestine contains small mucosal projections called villi to increase surface area aiding in absorption. Lacteals are specialized lymphatics in the villi that contain components to assist in the transportation of dietary fats and nutrients. Mucosal-associated lymphatic tissue (MALT) or gut-associated lymphoid tissue (GALT) is responsible for antigen sampling and initiation of immune responses. Obstruction of the lymphatic system can lead to debilitating conditions including protein-losing enteropathies, hereditary lymphedemas, lymphangiomas, lymphangiomatosis, and irritable bowel disease. Lymph node metastasis is important for cancer staging and the determination of a proper treatment course.