Blood, deoxygenation pressure

Lymphatic vessels infiltrate tissues that are bathed in fluid released from blood into those tissues. Pockets of fluid collect in the tissues, and increased pressure allows the fluid to seep into the lymphatic vessels. Whereas blood vessels return deoxygenated blood to the heart to be pumped to the lungg for oxygen, lymphatic vessels return fluid that has leaked out of the capillaries into various tissues. However, before this lymphatic fluid is rejoined with venous fluid at the thoracic duct, it is filtered through the lymph nodes to remove infectious agents. 

Figure 6.6. The physiological carbon dioxide dissociation curve for a normal person at rest. The points A and V represent partial pressures and contents of arterial and mixed venous blood respectively. As with the oxygen dissociation curve, this physiological carbon dioxide dissociation curve-moves between the two curves plotted with constant partial pressures of oxygen corresponding to oxygenated and deoxygenated blood.

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