The lymphoid gland that destroys worn-out blood cells is located behind the stomach (C). This gland is called the spleen, and it is an important part of the lymphatic system. The spleen helps to filter the blood, removing old or damaged red blood cells and other debris. It also helps to fight infections by producing white blood cells and antibodies. The spleen is located in the upper left part of the abdomen, behind the stomach, and is protected by the rib cage.