The Lymphatic System

“The lymphatic system is a vital and integral part of the cardiovascular system”. The lymphatic system contains many structures which consist of lymphatic vessels, lymph fluid, lymph cells, lymph nodes and other substances. (Hastie, 2012) The lymphatic system consists of a network of fine tubes or vessels which ramify throughout the body similar to blood vessels. Unlike the blood the fluid is moved by the muscles and limbs. The lymph vessels have fine walls, so water can pass easily through them. The main role of the lymphatic system is too drain off excess fluid from all parts of the body. This prevents the cells getting waterlogged. (Hayes, 2002). Other functions include returning the lymph back to the heart and immune surveillance within

They arise in the interstitial spaces of organs and tissues and they then join with the large veins just before they enter the vena cava of the heart. These lymphatic vessels tend to run parallel with the veins which allows filtration to occur. The vessels are non- muscular and contain valves which stop the fluid from going back. (Hastie, 2012). Lymph Fluid: Is excess tissue fluid that is found throughout the body in the lymph node, spleen and thymus. The Lymph fluid leaves blood capillaries and sits in the interstitial space. The fluid contains waste materials from tissues. They filter foreign debris and bacteria from lymph and transport large proteins and fats to the blood. The thoracic duct, which travels from the abdomen to the thorax is the main lymphatic duct that drains lymph into one of the large veins to the heart. The Lymph fluid is filtered through the lymph nodes before it enters the blood. (Reeder, Miller, Wilfong, Leitch & Zimmel.,

Rather than lymph fluid being circulated, it is blood. The spleen is the only organ specialized to filter blood. “The horse spleen is a large, bluish-red, funnel-shaped organ with a sponge-like texture. It is wedged between the kidney and the small colon on the left side of the abdomen.” The spleen is also used to target useless or dangerous debris, saving many necessities of the circulatory system. Witty, E. (2011) Three Facts About Your Horse’s Spleen. Available at: https://equusmagazine.com/management/in-focus-your-horsee28099s-spleen (Accessed: 16/11/17)

The spleen stores blood. The spleen is made up of two types of tissue which consist of the red pulp and white pulp. The function of the red pulp is to store and remove red blood cells. The white pulp consists of localised areas of lymphoid tissue within the spleen and produces the lymphocytes. ( Reeder et al., 2009).

Fluid enters the lymphatic system and returns it to the circulatory system. The fluid enters the system through the lymph vessels. The lymphatic vessels convert into larger vessels termed lymphatic veins which have lymphatic ducts which contain valves which prevent the backflow of the lymph fluid. These veins contain smooth muscles which also helps the movement of fluid. These veins lead to the lymph nodes. After the lymph is filtered in the node it then travels through the efferent lymphatic vessels that drain into the circulatory system veins