Just as the army, navy and air force is trained to protect the country from infiltrators and other countries, the various organs of the immune system are responsible for protecting the body from parasitic, bacterial, viral, fungal infections and growth of tumor cells. The immune system comprises immune system organs, which in turn are composed of several interdependent cells, that kill tumor and parasitic cells, destroy viral-infected cells and engulf bacteria. Organs of the immune system make cells, that either contribute in the immune response, or act as sites for the immune function.

Major Organs of the Immune System

The main organs in the immune system are the bone marrow, thymus, spleen and lymph nodes. Let us have a look at these immune system organs and functions.

Bone Marrow: All the cells of the human immune system are formed in the bone marrow, found within the bones, by a process called hematopoiesis. The process of hematopoiesis involves differentiation of bone-marrow-derived stem cells, either into mature cells of the immune system or precursor of cells which move out of the bone marrow and continue their maturation elsewhere. The bone marrow is responsible for the production of important immune system cells like B cells, granulocytes, natural killer cells and immature thymocytes. It also produces red blood cells and platelets.
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