MODULE SUPPLEMENT: IMMUNE SYSTEM
Phagocytosis

Phagocytosis: by cells within the classification of white blood cells or leukocytes

Phagocytic cells are extremely important. These cells "eat" or engulf and destroy various foreign substances or debris that must be eliminated. Several of these phagocytic cells are very important in the initiation of the specific immune response.

To better understand the components of the immune system and the way they inter-related, we need to take a closer look at the Leukocytes or White Blood Cells. Blood cell production is called Hematopoiesis, and all blood cells derive from a common pluripotent stem cell - meaning it can evolve in many possible directions.

Do changes occur at this level? Burns and Goodwin (1997) suggest that in some studies in certain mice strains the stem cells are defective in their ability to generate precursor cells, but how relevant this is for humans is not yet determined. 

In terms of the cells themselves, the myeloid precursor derived cells, specifically the monocytes and granulocytes, act as components of the non-specific immune system while the lymphoid precursor derivatives belong to the specific immune system.

Monocytes become macrophages in the tissues and are extremely important phagocytic cells that go by different names in different tissues.