This piece of writing will examine the lymphatic system. It will look into the anatomy and physiology of the components and their functions. Throughout; the lymphatic system, cardiovascular system, and immune system will all be looked at together to show how they work together. It will also look at the assessment of this system and what ethical issues may arise from a clinician carrying out these assessments. The lymphatic system will return any fluids that have been removed from the blood and move it from the vascular system to the blood circulation. This may seem straightforward but it is actually very complex. The lymph fluid is rich in nutrients and oxygen, it will also contain cellular waste and toxins. The lymph is only called lymph once it is in the vessels. Before this the lymph is known as interstitial fluid, this is formed through the hydrostatic and osmotic pressures within the capillaries pushing out fluid from the blood as it passes. The fluid will come out of the capillaries at the arterial end, most can then be reabsorbed at the venous end. The fluid not reabsorbed will form part of the interstitial fluid. The fluid that is removed from the blood must then be replaced. It must be replaced otherwise the cardiovascular system will not have a sufficient volume needed. This is resolved by the work of the lymphatic vessels. The lymphatic vessels will transport the lymph. It will take it from the peripheral tissues and transport it to the cardiovascular system. These vessels will therefore form a one way system that moves lymph to the heart. The journey the lymph takes first starts in “the microscopic blind-ended lymphatic capillaries” referring to Marieb (2016). These are found within the connective tissues, they are then “weaved between blood capillaries and tissue cells” marieb (2016). These capillaries are very permeable. This is due to the mini valves formed within them, they are formed by the epithelial cells making up the walls of the capillaries not being tightly packed together and instead overlapping one another slightly. The other factor making them permeable are the collagen strands which hook onto the endothelial cells of the structures around them. This structure ensures that if there is an increase in the volume of interstitial fluid outside the capillaries then the volume inside the capillaries , the valves will open allowing fluid to flow into the capillaries. Therefore if the volume of fluid is greater inside the capillaries than outside the valves will be shut off so the fluid cannot leak out and the pressure will move the fluid along.