Apoptosis

In biology, apoptosis (from the Greek words apo = from and ptosis = falling, pronounced ap-a-tow'-sishttp://www.nih.gov/sigs/aig/Aboutapo.html) is one of the main types of programmed cell death (PCD). As such, it is a process of deliberate suicide by an unwanted cell in a multicellular organism. In contrast to necrosis, which is a form of cell death that results from acute tissue injury, apoptosis is carried out in an ordered process that generally confers advantages during an organism's life cycle. For example, the differentiation of human fingers in a developing embryo requires the cells between the fingers to initiate apoptosis so that the fingers can separate. As will be explained further on, the way the apoptotic process is executed facilitates the safe disposal of cell corpses and fragments.

Related Topics:
Biology - Greek - Programmed cell death - Suicide - Cell - Organism - Necrosis - Human - Finger - Embryo

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Since the beginning of the 1990s, research on apoptosis has grown spectacularly. In addition to its importance as a biological phenomenon, defective apoptotic processes have been implicated in a very wide variety of diseases. Too much apoptosis causes cell-loss disorders, while too little results in uncontrolled cell proliferation, namely cancerous tumors.

Related Topics:
1990s - Cancer - Tumor

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Not all forms of PCD share the characteristic shapes (the morphology) and sequences of apoptosis, but all types of PCD are highly regulated processes.

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