when do you consider a dead man?When their heart stops to beat, or when the brain dies?
359825
Death is the cessation of physical life.\n\nHistorically, attempts to define the exact moment of 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 posed a challenge, rendering the previous definition inadequate. This earlier definition of death is now called "clinical death", and even after it occurs, breathing and heartbeat may be restarted in some cases. Events which were causally linked to death in the past are now prevented from having an effect; even without a functioning heart and lungs, a person can be sustained with life-support devices. In addition to such extremes, there is a growing number of people who would quickly die if their organ transplants or cardiac pacemakers failed.\n\nToday, 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 (cf. persistent vegetative state). It is presumed that a stoppage of electrical activity indicates the end of consciousness. However, suspension of consciousness must be permanent, and not transient, as occurs during sleep, and especially a coma. In the case of sleep, EEGs can easily tell the difference. Identifying the moment of death is important in cases of transplantation, as organs for transplant (the brain excluded) must be harvested as quickly as possible after the death of the body.\n\nMore: http://en.wikipedia.org/wiki/Death
733955
Clinically dead means you have no vital signs. Legally dead -to receive a death certificate- is diagnosed as being brain dead-no brain activity- by a qualified physician
1155242
When you're comatosed or dead
337258
After you die the brain live for about 7 minutes. \n\nI have heard that these 7 minutes hold the answer to the question, "what is heaven". I believe in this 7 minute unconscious stupor, you dream. And as everyone knows, time passes at a different rate when you dream. So in these 7 minutes you could be in a dream which is perceived as endless. And in this endless dream you re-live your life and dream of a heavenly place. The body can not perceive the difference between dream states and conscious states, and basically reacts the same to both. So in reality you really do go to heaven, and never wake up. But this is conditional of course on how you lived your life. If you die with a guilty conscious, your last dream will be a direct result of the way you lived. For instance you may have a nightmare after you eat late at night, just as you may go to hell in your last eternal dream if you let a miserable existence. I think religious figureheads caught onto this concept early on and have capitalized on it since.\n\nPlease e-mail me to discuss jodiamon@syr.edu or visit my blog which discusses this subject to death at http://krunkbox.blogspot.com/
1030421
death is physical\nsoul never dies it always sustain\nand soul is like a part of god and it is always remain inside a human to direct him in a right path but its all the brain of human who took decision
376444
This is a more complex question than it seems. In order to fully define Death we would have to fully define Life, and that has not been done yet. Life can be described, and there is the Cell Theory of Life, but what 'life' is, no one can say yet.\nHowever, it is plain that everything living moves somehow, and that it reproduces somehow, and that whatever is living must use and excrete whatever substances it needs in order to keep on living. In most cases we are talking here about nutrition and respiration, respiration being the more critical. When respiration ceases either on a cellular level or throughout the entire organism, everything shuts down, because chemical reactions in the cells and between them can no longer take place. Some bacteria will go into a spore stage when this happens, and can thus survive extremes of temperatures and dehydration (like anthrax and TB). Generally in the absence of oxygen, cells lose their ph balance and become acidic, which upsets all chemical reactions in the cell. Conversely, anaerobic bacteria like botulism, when exposed to oxygen, go through a similar process of having all chemical reactions messed up.\nTherefore, although we cannot say what exactly 'death' is, we recognize it in animals by: an absence of respiration, an absence of pulse, an absence of reflexes (due to brain and nerve death), an absence of sensation, an absence of conciousness, and an inability to eat or reproduce. It is further noted by an absence of brain wave activity.\nIn plants death is noted by an inability to rehydrate, lack of response to stimuli, inability to reproduce or respire, and limpness.\nIn microbes, death is noted by an absence of cell division or reproduction, or by bursting of the cell walls.
190137
As far as pronouncing a human dead they must fulfill certain requirements:\n-Response to pain – a highly scientific object, such as a key is pressed down onto the thumbnail very hard, someone living should react.  In this test we are looking for brain activity.\n-Pupil response to light – a light is directed into the pupil of the eye (both left and right), the pupil should contract if the person is living.  Again this test is looking for brain function.\n-A heartbeat and pulse.\n-Signs of breathing.\nIf a presumed dead person has no response to pain, no response to light, no evidence of a heartbeat or pulse, and no signs of breathing, the person is considered dead.  If the person does not meat one of these they are considered alive.\n\nFrom a pure biological standpoint this is a far more difficult question however.  Take a tree for instance.  The tissues in the leaves can be very much alive, undergoing all manor of metabolism from photosynthesis and respiration through to synthesis of fatty acids.  However in the same tree the cells that make up the xylem (water carrying tissue) are completely dead – these cells have long died leaving only their cell walls to remain.
673406
Theoretically your brain will not be dead, but "alive" is a sensation created by the input of all your senses.  Without sense a brain is just a box of memories.  You would be as "alive" as you are in your dreams.
817450
The person under there is dead. The do not see, feel, think or breathe. They do not get offended when the lawnmower runs over their grave.\n\nThe important thing is that you remember those who are dead, not how you visit their grave.
481655
when we die, our brains die too.. so, we can no longer think or be aware of anything. if its true that we dont have spirits, then, when we die, we just stop existing. but if we have spirits, then, when our bodies die, the spirit will just move alone without the body.
1108564
Scientificaly speaking, your are technically dead when your brainwaves stops and synapsis quit functioning in your brain.
468436
Determining when death actually occurs\n\nHistorically, attempts to define the exact moment of 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 posed a challenge, rendering the previous definition inadequate. This earlier definition of death is now called "clinical death", and even after it occurs, breathing and heartbeat may be restarted in some cases. Events which were causally linked to death in the past are now prevented from having an effect; even without a functioning heart and lungs, a person can be sustained with life-support devices. In addition to such extremes, there is a growing number of people who would quickly die if their organ transplants or cardiac pacemakers failed.\n\nToday, 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 (cf. persistent vegetative state). It is presumed that a stoppage of electrical activity indicates the end of consciousness. However, suspension of consciousness must be permanent, and not transient, as occurs during sleep, and especially a coma. In the case of sleep, EEGs can easily tell the difference. Identifying the moment of death is important in cases of transplantation, as organs for transplant (the brain excluded) must be harvested as quickly as possible after the death of the body.\n\nAmong human beings, 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))\n\nHowever, those 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 likely 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. However, at present, in most places the more conservative definition of death — 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 case of Terri Schiavo brought the question of brain death and artificial sustainment to the front of American politics. Generally, in such contested cases the cause of death is anoxia. Oxygen deprivation for about seven minutes is sufficient to kill the cerebral cortex.\n\nEven in these cases, the determination of death can be difficult. EEGs can detect spurious electrical impulses when none exists, while there have been cases in which electrical activity in a living brain has been too low for EEGs to detect. Because of this, hospitals often have elaborate protocols for determining death involving EEGs at widely separated intervals.\n\nThere 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. Stories of people actually being buried alive (which must assume no embalming) led one inventor in the early 20th century to design an alarm system, with a bell and a cord that could be pulled from inside the coffin.\n\nBecause of the difficulties in determining death, under most emergency protocols, a first responder is not authorized to pronounce a patient dead; some EMT training manuals, for example, specifically state that a person is not to be assumed dead unless there are clear and obvious indications that death has occurred
1089234
first offall what kind of question is this my god ,no one can tell , the only one that can is the one that has been killed in the gillotine and the person is dead so how  can some one tell i do know that when a persons head is cut the brain function stay functioning at least seconds but the person is in some type of coma i dont think they know anything or feel anything but if they do it last only second we cant be sure .
730269
Yea... I died 3 times...total crashes in a hospital.  O2 sats to 0,  coma, 3 years to get up again.No O2, no heart beat, no nothing. Myabe some random firings of neurons in the dying brain, stimulating memory cells. No, there is no out of body experience after death, only those memories coming back fuzzily and random
330063
As long as I was dependent on someone else. Probably about 70 yrs old. But i might change my mind at 69yrs old. Who knows?\nLook after and enjoy yourself instead of dwelling on death. Both living aqnd death only come once.\nI've never hear someone come back and say "It's great being dead! How's you life?"\nEnjoy, but not at someone else's expense! Good health!
475952
are you into dead bodies?
599928
On two separate occasions, my heart and breathing stopped and I was essentially dead until resuscitated with CPR.\n\nI did not see any afterlife.