The spleen is an important organ in the immune system and plays a vital role in the destruction of old and damaged red blood cells (RBCs). As RBCs age, they become less flexible and more prone to getting trapped in small blood vessels. The spleen filters out these damaged RBCs and removes them from circulation by phagocytosis. The phagocytosed RBCs are broken down and the components are recycled. The spleen also plays a role in storing and releasing platelets and white blood cells, and helps in the immune response to infections.