Solution

The spleen is the largest lymphatic organ in the body and is positioned in the superior abdomen. The spleen plays important roles in regard to red blood cells and the immune system. It removes old red blood cells and holds a reserve of blood, which can be valuable in case of hemorrhagic shock, blood loss and also recycles iron. It purifies the blood and helps the immune system to recognize and attack foreign antibodies and disease. The spleen is composed of the red and white pulp. The white pulp produces and grows immune cell as well as blood cells. On the other hand, the red pulp is responsible for purifying the blood and removing dead or old blood cells. The spleen has important hematopoietic functions up until the fifth month of gestation. After birth, erythropoietic functions cease, except in some hematologic disorders. As a major lymphoid organ, the spleen retains the ability to produce lymphocytes and, as such, remains an hematopoietic organ.