Which system picks up fluid leaked from blood vessels and returns it to the blood?

• A. Lymphatic system
• B. Digestive system
• C. Nervous system
• D. Respiratory system

Answer: (A)

The lymphatic system is responsible for picking up fluid that leaks out of blood vessels and returning it to the bloodstream. Capillaries leak small amounts of plasma into the surrounding tissue, creating interstitial fluid. Lymphatic capillaries absorb this fluid as lymph, transport it through a network of vessels and nodes, and eventually deliver it back into the circulatory system, helping maintain blood volume and tissue fluid balance. This system also supports immune function by carrying immune cells and filtering pathogens along the way. The digestive, nervous, and respiratory systems have other roles—digesting and absorbing nutrients, transmitting nerve signals, and exchanging gases, respectively—so they don’t perform the task of reclaiming leaked fluid back into the blood.