Controlling the number of cells within a tissue is performed by the proliferation and cell death, both involved in the maintenance of the number of cells within a tissue. Consequently, the cell cycle includes both the cell proliferation cycle and programmed cell death (apoptosis). Morphologically, apoptosis can be visualized microscopically. Some changes can be observed with the light microscope, sometimes using specific staining, and other changes can only be detected by transmission electron microscopy. Unlike necrosis, early changes involving nuclear chromatin condensation around the nuclear perimeter depend on the context, the separation of neighboring cells and the connections to the extracellular matrix. Plasma membrane protrusions or "blebs" appear and the completely condensed nucleus is divided into a number of fragments. Intact organelles are generally observed, although both endoplasmic reticulum dilatation and ribosome losses have been described. Sometimes cytoplasmic vacuoles have been described. Afterwards, the cells disintegrate into apoptotic bodies, which may contain any portion of the cellular material. Finally these apoptotic bodies are phagocytized by neighboring cells. Although this type of cell death was initially called "shrinkage necrosis" since it plays a complementary role to mitosis in the regulation of cell populations in various tissues, the term apoptosis was subsequently proposed [