Apoptosis - Short Essay

3011 WordsJan 7, 201313 Pages
Kerr, Wyllie, and Currie first used the term apoptosis in a paper in 1972 to describe a morphologically distinct form of cell death, although certain components of the apoptosis concept had been described years previously. Our understanding of the mechanisms involved in the process of apoptosis in mammalian cells transpired from the investigation of programmed cell death that occurs during the development of the nematode Caenorhabditis elegans (Horvitz, 1999). In this organism 1090 somatic cells are generated in the formation of the adult worm, of which 131 of these cells undergo apoptosis or “programmed cell death.” These 131 cells die at particular points during the development process, which is invariant between worms, demonstrating the…show more content…
Necrosis is an uncontrolled and passive process that usually affects large fields of cells whereas apoptosis is controlled and energy-dependent and can affect individual or clusters of cells. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma that result unregulated digestion of cell components Some of the major morphological changes that occur with necrosis include cell swelling; formation of cytoplasmic vacuoles; distended endoplasmic reticulum; formation of cytoplasmic blebs; condensed, swollen or ruptured mitochondria; disaggregation and detachment of ribosomes; disrupted organelle membranes; swollen and ruptured lysosomes; and eventually disruption of the cell membrane. This loss of cell membrane results in the release of the cytoplasmic contents into the surrounding tissue, sending chemotatic signals with eventual recruitment of inflammatory cells. Because apoptotic cells do not release their cellular constituents into the surrounding tissue and are quickly phagocytosed by macrophages or normal cells, there is essentially no inflammatory reaction. It is also important to note that pyknosis and karyorrhexis are not exclusive to apoptosis (Kurosaka et al., 2003). Mechanisms of Apoptosis The mechanisms of apoptosis are highly complex involving an energy dependent cascade of molecular events. Research
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