An organ in vertebrate animals that in humans is located on the left side of the abdomen near the stomach. The spleen is mainly composed of lymph nodes and blood vessels. It filters the blood, stores red blood cells (erythrocytes) and destroys old ones, and produces white blood cells (lymphocytes).

Your spleen: Stores blood. Filters blood by removing cellular waste and getting rid of old or damaged blood cells. Makes white blood cells and antibodies that help you fight infection. Maintains the levels of fluid in your body. Produces antibodies that protect you against infection. What are the parts of the spleen?

The word spleen comes from Ancient Greek σπλήν (splḗn). [ 1 ] The spleen plays very important roles in regard to red blood cells (erythrocytes) and the immune system. [ 2 ] It removes old red blood cells and holds a reserve of blood, which can be valuable in case of hemorrhagic shock, and also recycles iron.

In adults, the spleen is about the size of an avocado. The spleen is part of your lymphatic system (which is part of your immune system). It does several important jobs to keep your body healthy. Many different conditions, diseases, disorders and injuries affect how your spleen works.