The lymphatic system is a part of the circulatory system, that consists of a network of vessels called lymphatic vessels. These vessels carry a clear fluid called lymph towards the heart. The lymphatic system is not a closed system. The circulatory system processes an average of 20 litres of blood per day through capillary filtration which removes plasma while leaving the blood cells. Roughly 17 litres of the filtered plasma actually get reabsorbed directly into the blood vessels, while the remaining 3 litres are left behind in the interstitial fluid. This is due to the different pressures and water potential at either end of the capillaries. The primary function of the lymph system is to provide an accessory route for these excess 3 litres per day to get returned to the blood.  Because of this, lymph is essentially recycled blood plasma. Lymphatic organs also play an important part in the immune system, having a considerable overlap with the lymphoid system. Lymphoid tissue is found in many organs, particularly the lymph nodes, and in the lymphoid follicles associated with the digestive system such as the tonsils. Lymphoid tissues contain lymphocytes, but they also contain other types of cells for support. The system also includes all the structures dedicated to the circulation and production of lymphocytes (the primary cellular component of lymph), which includes the spleen, thymus, bone marrow, and the lymphoid tissue associated with the digestive system. The blood does not directly come in contact with the parenchymal cells and tissues in the body, but constituents of the blood first exit the microvascular exchange blood vessels to become interstitial fluid, which comes into contact with the parenchymal cells of the body. Lymph is the fluid that is formed when interstitial fluid enters the initial lymphatic vessels of the lymphatic system. The lymph is then moved along the lymphatic vessel network by either intrinsic contractions of the lymphatic...
References: 1. "Lymph - Definition and More from the Free Merriam-Webster Dictionary". www.merriam-webster.com. Retrieved 2010-05-29.
2. Human Physiology: From Cells to Systems, by Lauralee Sherwood
3. Tak W. Mak; Mary E. Saunders (Ph.D.); Mary E. Saunders (2008). Primer to the immune response. Academic Press. pp. 28–. ISBN 978-0-12-374163-9. Retrieved 12 November 2010.
4. Warwick, Roger; Peter L. Williams. "Angiology (Chapter 6)". Gray 's anatomy. illustrated by Richard E. M. Moore (Thirty-fifth ed.). London: Longman. pp. 588–785.
5. Wisco, Jonathan. "Lymphatic System". AnatomyOne. Amirsys, Inc. Retrieved 26 October 2012.
6. "The functions of the Lymphatic System.". Retrieved Feb. 25, 2011.
Please join StudyMode to read the full document