What distinguishes the spleen from lymph nodes?

The distinguishing feature of the spleen compared to lymph nodes is that the spleen filters blood. Unlike lymph nodes, which are primarily involved in filtering lymph fluid and facilitating an immune response to pathogens found in the lymph, the spleen serves a different function in the body's immune system. It filters the blood to remove old or damaged red blood cells, recycling iron and other components, and acts as a reservoir for blood. Additionally, the spleen plays a critical role in the immune response by producing and storing lymphocytes, which are key to mounting an immune defense, particularly against blood-borne pathogens.

While size can vary and the spleen is generally larger than individual lymph nodes, it is the function of filtering blood that sets the spleen apart in terms of its anatomical and physiological roles within the body. The production of antibodies is typically associated with lymphocytes rather than a function solely attributed to the spleen itself.