Continue with the anatomy and physiology of the Leukocytes. The 5 different types were mentioned and seen as a microphotograph of a drop of blood. The differences in structure were noted, and the major function of the cells in general discussed, that of protection against invading pathogens. Leukemia was discussed as a disease, its etiology and how it is treated using chemotherapy. The main effect of the chemo agents was discussed, along with the reason why some of the obvious side effects are seen.