Johnny Rae F. You

Biological Death...

Death is the irreversible ending of life. Biologically, death can occur to wholes, to parts, or to both. For example, it is possible for individual cells and even organs to die, and yet for the organism as a whole to continue to live; many individual cells live for only a short time, and so most of an organism's cells are continually dying and being replaced by new ones. An organism can actively kill its own cells through the processes of programmed cell death and necrosis. When organisms die most of their cells live for some time afterward. Organs can then be removed for transplantation. Irreversibility is often cited as a key criterion of death. By definition, a dead organism cannot be brought back to life; if it were to be, that would indicate that it had never been dead. Biochemically, it is unrealistic to think that death could be reversed. As soon as tissues die, autolysis sets in and enzymes begin to destroy the cells. A common misconception is that the Second Law of Thermodynamics dictates that all complex systems must eventually deteriorate, so it is not likely that any species could ever be immortal. However, this aspect of the Second Law applies only to closed systems, which organisms are not.