Final answer:
The lymphatic system returns 15% of the capillary filtrate to the blood. This is part of the fluid balance managed by capillaries and lymphatic vessels, filtering through lymph nodes before re-entry into the bloodstream.
Step-by-step explanation:
The percentage of capillary filtrate returned to the blood by the lymphatic system is 15%.
In the human body, fluid exchange occurs at the capillary level with some of this fluid then being collected by the lymphatic system. Approximately 20 liters of plasma is released into the interstitial space each day due to capillary filtration, and of this, 17 liters directly reabsorbed by the blood vessels. The remaining 3 liters, which constitutes about 15%, is taken up by the lymphatic system.
These lymphatic vessels ensure that the excess fluid, now referred to as lymph, is returned to the bloodstream. The lymph passes through lymph nodes where it is filtered, ensuring that by the time it rejoins the circulatory system, it is free from infectious agents.