Final answer:
The lymphatic system picks up the 15% to 20% of fluid not reabsorbed into the capillaries, filters it through lymph nodes, and then returns it to the bloodstream.
Step-by-step explanation:
The 15% to 20% of fluid that isn't reabsorbed into the capillary is picked up by the lymphatic system and filtered before it is returned to the blood. This excess fluid is collected by the lymphatic capillaries, which are thin-walled vessels with many valves that ensure unidirectional flow. The collected lymph passes through lymph nodes, where it is filtered and cleansed of any infectious agents by white blood cells. Afterward, the cleaned lymph returns to the bloodstream via the subclavian veins. This process is vital for maintaining fluid balance in the body and for the immune system's ability to fight infections.
The remaining 15% to 20% of fluid that isn't reabsorbed into the capillary is picked up by the lymphatic system and filtered before it is returned to the blood. These extremely thin-walled vessels called lymphatic capillaries have valves to ensure unidirectional flow and eventually drain into the subclavian veins in the neck.