In human anatomy, the spleen is the largest lymphatic organ.
The spleen is located in the upper-left part of the abdomen, beneath the diaphragm and near the stomach. It filters blood rather than lymph, removing old or damaged red blood cells and helping recycle components such as iron. It also stores and activates immune cells.
Its white pulp contains lymphoid tissue involved in immune surveillance, while its red pulp filters blood through a network of sinuses and cords. The spleen can respond to blood-borne microbes, making it an important part of defense against certain infections.
A person can survive without a spleen, but splenectomy increases vulnerability to some encapsulated bacteria. The liver also filters blood and performs many immune-related functions, but it is not classified as the largest lymphatic organ. The spleen is sometimes called the body's blood filter because of its specialized circulation.