What Exchanges Between Ducts & Venous Systems?

The Venous System

• The venous system is a network of large and small veins that circulate blood without oxygen in it to the right half of the heart and from there to the lungs. The blood then receives oxygen from the lungs and is sent to the left half of the heart, which distributes the blood to the body's organs. During the process of circulation, some of the blood plasma builds up as interstitial fluid in the tissues of the body. If there was no way to remove this fluid, the result could be death. The lymphatic vessels drain the interstitial fluid so it doesn't build up and become dangerous.

Lymphatic Fluid

• Lymphatic fluid, or lymph, is made up of a mixture including water, salt, protein, urea and glucose. Even though it is partially derived from blood, lymphatic fluid is clear. Lymph is drained by the lymphatic vessels from the spaces in between the cells of the human body. The lymphatic vessels run beside the veins. All of the lymphatic fluid collected by the lymphatic vessels is sent to two places in the body: the right lymphatic duct and the thoracic duct.

The Right Lymphatic Duct

• The right lymphatic duct only handles lymphatic fluid collected from the upper right areas of the body. The right lymphatic duct takes the lymph that it has collected and moves it into the right subclavian vein near its juncture with the internal jugular vein. This causes all of the lymph that has been drained from the upper right part of the body to be reintroduced into the venous system at this point.

The Thoracic Duct

• The thoracic duct handles all of the lymph that is collected in other areas of the body besides the upper right area. This duct takes all of the lymphatic fluid that it has collected from the rest of the body and moves it into the venous system through the left subclavian vein where it connects with the internal jugular vein. Through this process, the body is protected from the buildup of otherwise dangerous fluids between the cells.