Death
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- For other uses of 'death' and 'deceased,' see Death (disambiguation)
Death is the permanent termination of the biological functions that define a living organism. It refers to both a particular event and to the condition that results thereby. The true nature of the latter has for millennia been a central concern of the world's religious traditions and of philosophical enquiry. Religions, almost without exception, maintain faith in either some kind of afterlife or reincarnation. The effect of physical death on any possible mind or soul remains an open question. Contemporary science regards organismic death as final by definition.
Not all animals die in due course from senescence (see the Hydra). Intervening phenomena which commonly bring death earlier include malnutrition, predation, disease, accidents resulting in terminal physical injury, or, in extreme circumstances, grave ecosystem disruption. Intentional human activity causing death includes suicide, homicide, and war. Roughly 150,000 people die each day across the globe.[1] Death in the natural world can also occur as an indirect result of human activity: an increasing cause of species depletion in recent times has been destruction of ecological systems as a consequence of the widening spread of industrial technology.[citation needed]
The chief concern of medical science has been to postpone and avert death. Death in this context is now seen as less an event than a process: conditions once considered indicative of death are now reversible. [2] Where in the process a dividing line is drawn between life and death depends on factors beyond the presence or absence of vital signs. In general, clinical death is neither necessary nor sufficient for a determination of legal death. A patient with working heart and lungs determined to be brain dead can be pronounced legally dead without clinical death occurring. Precise medical definition of death, in other words, becomes more problematic, paradoxically, as scientific knowledge and technology advance. Death remains a central mystery of life itself. [3]
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[edit] Biological death
[edit] Competition, natural selection and extinction
Death is an important part of the process of natural selection. Organisms that are less adapted to their current environment than others are more likely to die having produced fewer offspring, reducing their contribution to the gene pool of succeeding generations. Their genes are thus eventually bred out of a population, leading to processes such as speciation and extinction. It should be noted however that reproduction plays an equally important role in determining survival. For example, an organism that dies young but leaves many offspring will have a much greater Darwinian fitness than a long-lived organism which leaves only one.
[edit] Extinction
Extinction is the cessation of existence of a species or group of taxa, reducing biodiversity. The moment of extinction is generally considered to be the death of the last individual of that species (although the capacity to breed and recover may have been lost before this point). Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. Through evolutional theory, new species arise through the process of speciation — where new varieties of organisms arise and thrive when they are able to find and exploit an ecological niche — and species become extinct when they are no longer able to survive in changing conditions or against superior competition.
After death the remains of an organism become part of the biogeochemical cycle. Animals may be consumed by a predator or a scavenger. Organic material may then be further decomposed by detritivores, organisms which recycle detritus, returning it to the environment for reuse in the food chain. Examples of detritivores include earthworms, woodlice and dung beetles.
Microorganisms also play a vital role, raising the temperature of the decomposing matter as they break it down into yet simpler molecules. Not all material need be decomposed fully, however. Coal, a fossil fuel formed over vast tracts of time in swamp ecosystems, is one example.
[edit] Death and evolution
Enquiry into the evolution of aging aims to explain why so many living things and the vast majority of animals weaken and die with age (a notable exception being hydra, which may be biologically immortal). The evolutionary origin of senescence remains one of the fundamental puzzles of biology. Gerontology specializes in the science of human aging processes.
[edit] Defining death
[edit] Problems of definition
One of the challenges in defining death is in distinguishing it from life. Death would seem to refer to either the moment at which life ends or the state that follows life. However, determining when death has occurred requires drawing precise conceptual boundaries between life and death. This is problematic however because there is little consensus over how to define life. Some have suggested defining life in terms of consciousness. When consciousness ceases, a living organism can be said to have died. One of the notable flaws in this approach is that there are many organisms which are alive but not conscious (for example, single-celled organisms). Another problem with this approach is in defining consciousness, which remains a mystery to modern scientists, psychologists and philosophers. This general problem of defining death applies to the particular challenge of defining death in the context of medicine.
[edit] Defining death in medicine
Historically, attempts to define the exact moment of a human's death have been problematic. Death was once defined as the cessation of heartbeat (cardiac arrest) and of breathing, but the development of CPR and prompt defibrillation have rendered that definition inadequate because breathing and heartbeat can sometimes be restarted. Events which were causally linked to death in the past no longer kill in all circumstances; without a functioning heart or lungs, life can sometimes be sustained with a combination of life support devices, organ transplants and artificial pacemakers.
Today, where a definition of the moment of death is required, doctors and coroners usually turn to "brain death" or "biological death"; people are considered dead when the electrical activity in their brain ceases. It is presumed that an end of electrical activity indicates the end of consciousness. However, suspension of consciousness must be permanent, and not transient, as occurs during certain sleep stages, and especially a coma. In the case of sleep, EEGs can easily tell the difference.
The possession of brain activities, or ability to resume brain activity, is a necessary condition to legal personhood in the United States. "It appears that once brain death has been determined … no criminal or civil liability will result from disconnecting the life-support devices." (Dority v. Superior Court of San Bernardino County, 193 Cal.Rptr. 288, 291 (1983))
Many have challenged the idea that brain death is equivalent to the cessation of consciousness. Critics point out that much of human consciousness is embodied in numerous body parts and that the end of electrical impulses in the brain does not necessarily indicate that this embodied consciousness has also ceased. Given this possibility, brain death does not necessitate the end of consciousness, and thus brain dead people may still be alive. Furthermore, some have argued, even if brain death does mean the end of consciousness for a human being, the whole notion that cessation of consciousness indicates death is problematic. Critics note the existence of many simple organisms such as viruses that we consider to be alive but which many doubt are conscious. If life does not require consciousness, defining death in terms of "brain death" is a dubious procedure, even if the brain is the seat of consciousness. Thus while legal concerns surrounding death force us to develop a working definition of death, it is not at all clear that the current American definition, according to brain death, coincides at all with a definition that can be reasonably endorsed.[who?]
Those people maintaining that only the neo-cortex of the brain is necessary for consciousness sometimes argue that only electrical activity there should be considered when defining death. Eventually it is possible that the criterion for death will be the permanent and irreversible loss of cognitive function, as evidenced by the death of the cerebral cortex. All hope of recovering human thought and personality is then gone given current and foreseeable medical technology. However, at present, in most places the more conservative definition of death — irreversible cessation of electrical activity in the whole brain, as opposed to just in the neo-cortex — has been adopted (for example the Uniform Determination Of Death Act in the United States). In 2005, the Terri Schiavo case brought the question of brain death and artificial sustenance to the front of American politics.
Even by whole-brain criteria, the determination of brain death can be complicated. EEGs can detect spurious electrical impulses, while certain drugs, hypoglycemia, hypoxia, or hypothermia can suppress or even stop brain activity on a temporary basis. Because of this, hospitals have protocols for determining brain death involving EEGs at widely separated intervals under defined conditions.
[edit] Misdiagnosed death
There are many anecdotal references to people being declared dead by physicians and then 'coming back to life', sometimes days later in their own coffin, or when embalming procedures are just about to begin. Owing to significant scientific advancements in the Victorian era, some people in Britain became obsessively worried about living after being declared dead.[5]
In cases of electric shock, CPR for an hour or longer can allow stunned nerves to recover, allowing an apparently dead person to survive. People found unconscious under icy water may survive if their faces are kept continuously cold until they arrive at an emergency room.[6] This "diving response", in which metabolic activity and oxygen requirements are minimal, is something humans share with cetaceans called the mammalian diving reflex.[6]
As medical technologies advance, ideas about when death occurs may have to be re-evaluated in light of the ability to restore a person to vitality after longer periods of apparent death (as happened when CPR and defibrillation showed that cessation of heartbeat is inadequate as a decisive indicator of death). The lack of electrical brain activity may not be enough to consider someone scientifically dead. Therefore, the concept of information theoretical death has been suggested as a better means of defining when true death actually occurs, though the concept has few practical applications outside of the field of cryonics.
There have been some scientific attempts to bring dead organisms back to life, but with limited success.[7] In science fiction scenarios where such technology is readily available, real death is distinguished from reversible death.
[edit] Death and the law
By law, a person is dead if a Statement of Death or Death Certificate is approved by a licensed medical practitioner. Various legal consequences follow death, including the removal from the person of what in legal terminology is called personhood.
[edit] Human causes of death
Death can be caused by disease, suffocation/asphyxiation or prolonged lack of oxygen to the brain, or physical trauma as a result of an accident ("unintentional circumstance"), homicide ("intentional act by someone else"), or suicide ("intentional act against one's self").[8]
The leading cause of death in developing countries is infectious disease. The leading causes of death in developed countries are atherosclerosis (heart disease and stroke), cancer, and other diseases related to obesity and aging. These conditions cause loss of homeostasis, leading to cardiac arrest, causing loss of oxygen and nutrient supply, causing irreversible deterioration of the brain and other tissues. Of the roughly 150,000 people who die each day across the globe, about two thirds — 100,000 per day — die of age-related causes.[1] In industrialized nations, the proportion is much higher, reaching 90%.[1] With improved medical capability, dying has become a condition to be managed. Home deaths, once normal, are now rare in the developed world.
In developing nations, inferior sanitary conditions and lack of access to modern medical technology makes death from infectious diseases more common than in developed countries. One such disease is tuberculosis, a bacterial disease which killed 1.7 million people in 2004.[9] Malaria causes about 400–900 million cases of fever and approximately one to three million deaths annually.[10] AIDS death toll in Africa may reach 90-100 million by 2025.[11][12]
According to Jean Ziegler, who was the United Nations Special reporter on the Right to Food from 2000 to March 2008; mortality due to malnutrition accounted for 58% of the total mortality rate in 2006. Ziegler says worldwide approximately 62 million people died from all causes and of those deaths more than 36 million died of hunger or diseases due to deficiencies in micronutrients."[13]
Tobacco smoking killed 100 million people worldwide in the 20th century and could kill 1 billion people around the world in the 21st century, the WHO Report warned.[14][15]
Many leading developed world causes of death can be postponed by diet and physical activity, but the accelerating incidence of disease with age still imposes limits on human longevity. The evolutionary cause of aging is, at best, only just beginning to be understood. It has been suggested that direct intervention in the aging process may now be the most effective intervention against major causes of death.[16]
[edit] Symptoms of death
Signs of death, or strong indications that a person is no longer alive are:
- Pallor mortis, paleness which happens almost instantaneously (in the 15–120 minutes after the death)
- Algor mortis, the reduction in body temperature following death. This is generally a steady decline until matching ambient temperature
- Rigor mortis, the limbs of the corpse become stiff (Latin rigor) and difficult to move or manipulate
- Livor mortis, a settling of the blood in the lower (dependent) portion of the body
- Decomposition, the reduction into simpler forms of matter
[edit] Autopsy
An autopsy, also known as a postmortem examination or an obduction, is a medical procedure that consists of a thorough examination of a human corpse to determine the cause and manner of a person's death and to evaluate any disease or injury that may be present. It is usually performed by a specialized medical doctor called a pathologist.
Autopsies are either performed for legal or medical purposes. A forensic autopsy is carried out when the cause of death may be a criminal matter, while a clinical or academic autopsy is performed to find the medical cause of death and is used in cases of unknown or uncertain death, or for research purposes. Autopsies can be further classified into cases where external examination suffices, and those where the body is dissected and an internal examination is conducted. Permission from next of kin may be required for internal autopsy in some cases. Once an internal autopsy is complete the body is generally reconstituted by sewing it back together. Autopsy is important in a medical environment and may shed light on mistakes and help improve practices.
A necropsy is an older term for a postmortem examination, unregulated, and not always a medical procedure.
[edit] The quest for life extension
Life extension refers to an increase in maximum or average lifespan, especially in humans, by slowing down or reversing the processes of aging. Average lifespan is determined by vulnerability to accidents and age or lifestyle-related afflictions such as cancer or cardiovascular disease. Extension of average lifespan can be achieved by good diet, exercise and avoidance of hazards such as smoking. Maximum lifespan is determined by the rate of aging for a species inherent in its genes. Currently, the only widely recognized method of extending maximum lifespan is calorie restriction. Theoretically, extension of maximum lifespan can be achieved by reducing the rate of aging damage, by periodic replacement of damaged tissues, or by molecular repair or rejuvenation of deteriorated cells and tissues.
Researchers of life extension are a subclass of biogerontologists known as "biomedical gerontologists". They try to understand the nature of aging and they develop treatments to reverse aging processes or to at least slow them down, for the improvement of health and the maintenance of youthful vigor at every stage of life. Those who take advantage of life extension findings and seek to apply them upon themselves are called "life extensionists" or "longevists". The primary life extension strategy currently is to apply available anti-aging methods in the hope of living long enough to benefit from a complete cure to aging once it is developed, which given the rapidly advancing state of biogenetic and general medical technology, could conceivably occur within the lifetimes of people living today.
Many biomedical gerontologists and life extensionists believe that future breakthroughs in tissue rejuvenation with stem cells, organs replacement (with artificial organs or xenotransplantations) and molecular repair will eliminate all aging and disease as well as allow for complete rejuvenation to a youthful condition. Whether such breakthroughs can occur within the next few decades is impossible to predict. Some life extensionists arrange to be cryonically preserved upon legal death so that they can await the time when future medicine can eliminate disease, rejuvenate them to a lasting youthful condition and repair damage caused by the cryonics process.
[edit] Death in culture
Death is the center of many traditions and organizations, and is a feature of every culture around the world. Much of this revolves around the care of the dead, as well as the afterlife and the disposal of bodies upon the onset of death. The disposal of human corpses does, in general, begin with the last offices before significant time has passed, and ritualistic ceremonies often occur, most commonly interment or cremation. This is not a unified practice, however, as in Tibet for instance the body is given a sky burial and left on a mountain top. Mummification or embalming is also prevalent in some cultures, to retard the rate of decay.
Such rituals are accompanied by grief and mourning in almost all cases, and this is not limited to human loss, but extends to the loss of an animal. Legal aspects of death are also part of many cultures, particularly the settlement of the deceased estate and the issues of inheritance and in some countries, inheritance taxation.
Capital punishment is also a divisive aspect of death in culture. In most places that practice capital punishment today, the death penalty is reserved as punishment for premeditated murder, espionage, treason, or as part of military justice. In some countries, sexual crimes, such as adultery and sodomy, carry the death penalty, as do religious crimes such as apostasy, the formal renunciation of one's religion. In many retentionist countries, drug trafficking is also a capital offense. In China human trafficking and serious cases of corruption are also punished by the death penalty. In militaries around the world courts-martial have imposed death sentences for offenses such as cowardice, desertion, insubordination, and mutiny.[17]
Death in warfare and in suicide attack also have cultural links, and the ideas of dulce et decorum est pro patria mori, mutiny punishable by death, grieving relatives of dead soldiers and death notification are embedded in many cultures. Recently in the western world, with the supposed increase in terrorism following the September 11 attacks, but also further back in time with suicide bombers and terrorism in Northern Ireland, kamikaze missions in World War II and suicide missions in a host of other conflicts in history, death for a cause by way of suicide attack, and martyrdom have had significant cultural impacts.
Suicide in general, and particularly euthanasia are also points of cultural debate. Both acts are understood very differently in contrasting cultures. In Japan, for example, ending a life with honor by seppuku was considered a desirable death, whereas according to traditional Christian and Islamic cultures, suicide is viewed as a sin. Death is also personified in many cultures, with such creations as the Grim Reaper, Azrael, Father Time. Such cultural ideas are part of a global fascination with death.
Abortion is the deliberate termination of a human pregnancy. This is partially legalised in many Western countries if the mother requests it, and a doctor prescribes it, often taking into account the physical and mental state of the mother-to-be, and the development of the fetus. In countries where abortion is legal, the understanding is that the rights of the mother outweigh any rights of the fetus. Some ethicists and religious groups argue that this is wrong and that the fetus has a right to life. In countries where abortion is illegal, many "back-alley" (unsafe abortions) may still occur with great risk to the health of the mother.
[edit] See also
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[edit] References
- ^ a b c Aubrey D.N.J, de Grey (2007). "Life Span Extension Research and Public Debate: Societal Considerations" (PDF). Studies in Ethics, Law, and Technology 1 (1, Article 5). doi:. http://www.mfoundation.org/files/sens/ENHANCE-PP.pdf. Retrieved on March 20, 2009.
- ^ Crippen, David. "Brain Failure and Brain Death: Introduction". ACS Surgery Online, Critical Care, April 2005. http://www.acssurgery.com/abstracts/acs/acs0812.htm. Retrieved on 2007-01-09.[dead link]
- ^ The Hour of Our Death, Philippe Ariès, 1981
- ^ Diamond, Jared (1999). "Up to the Starting Line". Guns, Germs, and Steel. W. W. Norton. pp. 43–44. ISBN 0-393-31755-2.
- ^ As reflected from at least one article of literature by authors like Edgar Allan Poe, where subjects were buried alive.
- ^ a b Limmer, D. et al. (2006). Emergency care (AHA update, Ed. 10e). Prentice Hall.
- ^ Blood Swapping Reanimates Dead Dogs
- ^ WHO: 1.6 million die in violence annually
- ^ World Health Organization (WHO). Tuberculosis Fact sheet N°104 - Global and regional incidence. March 2006, Retrieved on 6 October 2006.
- ^ USAID’s Malaria Programs
- ^ Aids could kill 90 million Africans, says UN
- ^ AIDS Toll May Reach 100 Million in Africa, Washington Post
- ^ Jean Ziegler, L'Empire de la honte, Fayard, 2007 ISBN 978-2-253-12115-2 p.130.
- ^ Tobacco Could Kill One Billion By 2100, WHO Report Warns
- ^ Tobacco could kill more than 1 billion this century: WHO
- ^ SJ Olshanksy et al. (2006). "Longevity dividend: What should we be doing to prepare for the unprecedented aging of humanity?". The Scientist (Scientist (The), Philadelphia) 20: 28–36. http://www.grg.org/resources/TheScientist.htm. Retrieved on 2007-03-31.
- ^ "Shot at Dawn, campaign for pardons for British and Commonwealth soldiers executed in World War I". Shot at Dawn Pardons Campaign. http://www.shotatdawn.org.uk/. Retrieved on 2006-07-20.
[edit] Additional references
- Pounder, Derrick J. (2005-12-15). "POSTMORTEM CHANGES AND TIME OF DEATH". University of Dundee. http://www.dundee.ac.uk/forensicmedicine/notes/timedeath.pdf. Retrieved on 2006-12-13.
- Appel, JM. Defining Death: When Physicians and Families Differ” Journal of Medical Ethics Fall 2005.
- Vass AA (2001) Microbiology Today 28: 190-192 at: [1]
- Piepenbrink H (1985) J Archaeolog Sci 13: 417-430
- Piepenbrink H (1989) Applied Geochem 4: 273-280
- Child AM (1995) J Archaeolog Sci 22: 165-174
[edit] External links
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Wikiquote has a collection of quotations related to: Death |
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Wikimedia Commons has media related to: Death |
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Look up death in Wiktionary, the free dictionary. |
- Death at the Open Directory Project
- Death (Stanford Encyclopedia of Philosophy)
- Doctors Change the Way They Think About Death
- Odds of dying from various injuries or accidents Source: National Safety Council, United States, 2001
- Causes of Death
- Causes of Death 1916 How the medical profession categorized causes of death a century ago.
- George Wald: The Origin of Death A biologist explains life and death in different kinds of organisms in relation to evolution.
- Before and After Death Interviews with people dying in hospices, and portraits of them before, and shortly after, death
- Video of Introductory lecture by Yale professor Shelly Kagan to the course "Philosophy of Life and Death"
| Preceded by Old age |
Stages of human development Death |
Succeeded by Decomposition |
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