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Human Body Study

Spleen

The largest lymphatic organ — fist-sized, in the upper left abdomen. It filters blood rather than lymph.

The lymphatic and immune system A stylised body with the lymphatic organs placed at their anatomical positions, plus two concept panels for the functional arms — innate immunity (phagocytes eating pathogens) and adaptive immunity (lymphocytes and antibodies). Each label links to the article for that part. Innate immunity fast frontline: phagocytes ingest pathogens Adaptive immunity specific and remembered: lymphocytes and antibodies Tonsils Thymus Lymph nodes Spleen Lymphatic vessels Bone marrow Lymphatic organs and lymph vessels, plus the two arms of the immune response — schematic.

What it does

Section titled “What it does”
  • Removes old or damaged red blood cells.
  • Filters the blood for microbes and mounts immune responses against blood-borne threats.
  • Stores a reserve of blood and platelets.

Key idea

Section titled “Key idea”

The spleen is the lymph node of the bloodstream — it can be removed and life continues, but with somewhat reduced defense against certain infections.