where does the lymphatic system begin and end
Lymphatic system The lymphatic system is part of the circulatory system and an important part of the immune system, comprising a network of lymphatic vessels that carry a clear fluid called lymph (from Latin, lympha meaning "water"[1]) directionally towards the heart. The lymphatic system was first described in the seventeenth century independently by Olaus Rudbeck and Thomas Bartholin. Unlike the circulatory system, the lymphatic system is not a closed system. The human circulatory system processes an average of 20 liters of blood per day through capillary filtration, which removes plasma while leaving the blood cells. Roughly 17 litres of the filtered plasma are reabsorbed directly into the blood vessels, while the remaining three litres remain in the interstitial fluid. One of the main functions of the lymph system is to provide an accessory return route to the blood for the surplus three litres.[2]
Chylomicron Chylomicrons are formed in the endoplasmic reticulum in the absorptive cells (enterocytes) of the small intestine. The villi, lined with the microvilli of the brush border, provide a lot of surface area for absorption. Newly formed chylomicrons are secreted through the basolateral membrane into the lacteals, where they join lymph to become chyle. The lymphatic vessels carry the chyle to the venous return of the systemic circulation. From there the chylomicrons supply the tissue with fat absorbed from the diet.[2] Thus, unlike the saccharides and amino acids that digestion liberates from the carbohydrates and proteins of the diet (respectively), the lipids from the diet bypass the hepatic portal system, meaning the liver does not get "first crack" at them.