Understanding the Anatomy and Function of Lymph Nodes

3. Lymph

Interstitial fluid exists in the spaces around cells. It helps carry oxygen and nutrients to cells and remove waste from them. The interstitial fluid becomes lymph when it enters the lymphatic system through the lymph capillaries. Because lymph originates from the interstitial fluid, its composition is ever-changing. Blood and the surrounding cells constantly exchange substances with interstitial fluid, and lymph transports many of these substances. For example, it returns proteins and excess interstitial fluid to the bloodstream while simultaneously collecting bacteria for delivery to the lymph nodes.