What system is responsible for collecting excess fluid from interstitial space?

The lymphatic system is primarily responsible for collecting excess fluid from the interstitial space, which is the area surrounding cells. This system plays a crucial role in maintaining fluid balance within the body by draining excess fluid that leaks from blood capillaries into the surrounding tissues. If this fluid is not returned to the bloodstream, it can lead to swelling and edema. The lymphatic vessels transport this excess fluid, now called lymph, back to the circulatory system, ensuring that the body maintains proper fluid levels and thus facilitating the overall health of tissues.

In contrast, the cardiovascular system's main role is to circulate blood throughout the body, the respiratory system is focused on the exchange of gases (oxygen and carbon dioxide) in the lungs, and the digestive system is responsible for the breakdown of food and absorption of nutrients. While all these systems are vital for bodily function, the specific task of collecting and returning excess interstitial fluid is distinctly the role of the lymphatic system.