The spleen acts as a inspection center for red blood cells. Blood flows through narrow channels inside the spleen, forcing red cells to squeeze through tight spaces. Healthy cells pass through easily because their membranes are flexible. Older red cells have stiffer membranes and become trapped. Once trapped, they are examined by phagocytes, which are immune cells specialized in removing damaged material. The phagocytes engulf the worn out red cells and break them down inside enzyme filled compa