death(redirected from biological death)
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death,cessation of all life (metabolic) processes. Death may involve the organism as a whole (somatic death) or may be confined to cells and tissues within the organism. Causes of death in human beings include injury, acute or chronic disease, and neoplasia (cancer). The physiological death of cells that are normally replaced throughout life is called necrobiosis; the death of cells caused by external changes, such as an abnormal lack of blood supply, is called necrosis.
Somatic death is characterized by the discontinuance of cardiac activity and respiration, and eventually leads to the death of all body cells from lack of oxygen, although for approximately six minutes after somatic death—a period referred to as clinical death—a person whose vital organs have not been damaged may be revived. However, achievements of modern biomedical technology have enabled the physician to artificially maintain critical functions for indefinite periods.
Somatic death is followed by a number of irreversible changes that are of legal importance, especially in estimating the time of death. These include rigor mortisrigor mortis
, rigidity of the body that occurs after death. The onset may vary from about 10 min to several hours or more after death, depending on the condition of the body at death and on factors in the atmosphere, particularly temperature.
..... Click the link for more information. , livor mortis (discoloration of the body due to settling of blood), algor mortis (cooling of the body), autolysis (breakdown of tissue by enzymes liberated by that tissue after death), and putrefaction (invasion of the body by organisms from the gastrointestinal tract).
Brain death, which is now a legal condition in most states for declared death, requires that the following be absent for at least 12 hours: behavioral or reflex motor functions above the neck, including pupillary reflexes to testing jaw reflex, gag reflex, response to noxious stimuli, and any spontaneous respiratory movement. Purely spinal reflexes can remain. If the patient has agreed to be an organ donor, the observation period can be shortened to 6 hours.
As a result of recent refinements in organ transplantation (see transplantation, medicaltransplantation, medical,
surgical procedure by which a tissue or organ is removed and replaced by a corresponding part, usually from another part of the body or from another individual.
..... Click the link for more information. ) techniques, the need has arisen to more precisely define medical death. The current definition is that of a 1981 U.S. presidential commission, which recommended that death be defined as "irreversible cessation of all functions of the entire brain, including the brain stem," the brain stem being that part of the brain that controls breathing and other basic body functions. Some feel, however, that people in persistent vegetative states, i.e., people who have brain-stem function but have lost higher brain functions (vision, abstract thought, personality), should be considered dead and allowed, through living willsliving will
or advance health care directive,
legal document in which a person expresses in advance his or her wishes concerning the use of artificial life support and other medical treatment should the person be unable to communicate such wishes due the effects of
..... Click the link for more information. or relatives, to donate organs.
, either painlessly putting to death or failing to prevent death from natural causes in cases of terminal illness or irreversible coma. The term comes from the Greek expression for "good death.
..... Click the link for more information. ; funeral customsfuneral customs,
rituals surrounding the death of a human being and the subsequent disposition of the corpse. Such rites may serve to mark the passage of a person from life into death, to secure the welfare of the dead, to comfort the living, and to protect the living from the
..... Click the link for more information. ; vital statisticsvital statistics,
primarily records of the number of births and deaths in a population. Other factors, such as number of marriages and causes of death, by age groups, are regularly included.
..... Click the link for more information. .
See E. Kübler-Ross, On Death and Dying (1969); S. B. Nuland, How We Die (1994).
the cessation of the vital functions of an organism and the ensuing end of its life as an individual. Death is accompanied by the decomposition of proteins and other biopolymers, which are the principal material substrate of life. Modern views of dialectic materialism on the subject of death are based on the following idea expressed by F. Engels: “One can no longer consider scientific a physiology that does not regard death as an essential aspect of life … or realize that the negation of life is an essential component of life: life must always be viewed in relation to its inevitable and immanent property—death” (K. Marx and F. Engels, Soch., 2nd ed., vol. 20, p. 610).
Sometimes the concept of partial death is proposed, that is, the death of a group of cells or of an organ or part of an organ. In unicellular organisms, or protozoa, the natural death of an individual is manifested by division; when the individual ceases its existence, two new individuals come into being to take its place. In the case of other organisms, death marks the definitive conclusion of the organism’s life, usually leading to the formation of a corpse.
In higher animals and man, death is termed natural or physiological when it results from prolonged, gradual extinction of the organism’s main vital functions. Premature, or pathological, death results from disease or from lesions of such vital organs as the brain, heart, lungs, and liver. Premature death may be sudden; it may occur within a few minutes or even seconds, as in myocardial infarction. Violent death may be caused by an accident, suicide, or murder.
The death of warm-blooded animals and man is caused mainly by the cessation of respiration and blood circulation. The two main stages of death are, successively, clinical death and biological or true death. Complete restoration of vital functions is possible during clinical death, but biological death involves an irreversible cessation of physiological processes in the cells and tissues. The discipline of thanatology studies the processes associated with death.
REFERENCESMetchnikoff, E. Etiudy optimizma, 4th ed. Moscow, 1917.
Shmal’gauzen, I. I. Problema smerti i bessmertiia. Moscow-Leningrad, 1926.
Il’in, N. A. Sovremennaia nauka o zhizni i smerti. Kishinev, 1955.
Lunts, A. M. “Ob evoliutsii smerti v sviazi s evoliutsiei razmnozheniia.” Zhurnal obshchei biologii, 1961, vol. 22, no. 2.
Policard, A., and M. Bessis. Elementy patologii kletki. Moscow, 1970. (Translated from French.)