Macrophages: Nature's Garbage Disposal

Remember the white blood cell called the monocyte? At some point in its development, it becomes a macrophage, which is Greek for "Large Eater." It's kind of like a powerful garbage disposal that is useful to our immune system because it can actually eat (the process of phagocytosis) foreign invaders, whether microbial or not. Here is a drawing of a phagocyte (macrophage) preparing to engulf an entire bacterium. Once the phagocyte surrounds the bacterium, it will destroy it by "digesting" it. Macrophages patrol the body looking for anything it can "eat." However, macrophages are particularly on the lookout for anything marked with a "special sign." Other white blood cells, especially the lymphocytes, attach antibodies to foreign microbes which effectively identifies the germ as something bad that needs to be destroyed.