Technology Scientific Background Cell Death and Apoptosis Living cells typically die by one of two mechanisms, necrosis or apoptosis.
Necrosis refers to traumatic cell death resulting from, for example a severe burn or injury.
Necrosis is usually caused by an external force. Apoptosis, or programmed cell death, refers to an orderly sequence of responses to biochemical or physical signals that end in cells dying. This is the body's attempt to get rid of unwanted or damaged cells. Most cells in the body have a predetermined life expectancy. Cell death is normally a tightly regulated process in which cells are constantly reacting to chemical signals from other cells or from their environment instructing them to live.