what does it mean to be clinically brain dead? how long does the brain functions after the heart stops?
143951
Just a small addition to the answer above: permanent brain damage occurs minutes after the heart stops, but  a  person becomes unconscious long before that (in the matter of seconds).
25481
when your heart stops working ("fails") it can no longer pump blood, so the blood backs up (becomes "congested")\n\nyour heart has 2 sides - left and right.  the right pumps blood from the body through the lungs, and the left pumps blood from the lungs to the body.  so in right heart failure, blood backs up into your body -- usually your liver, spleen and legs.  left heart failure backs blood up into your lungs.
407105
well, very inellgent question, first of all once the brain is dead, it cannot be  transplanted. the possibilities are very low. but, recently one experiment on brain transplantations were succeded in europe, some 26 days back.it wasn't an succeded 100%, but it showed 45% improments. and how the technology is! by the next few years it will be 100% possible!.it will be!
660535
the brain will remain active until the lack of blood supply "chokes" it.
615644
Have you not hear people asking HAVE YOU LOST YOUR BRAIN MIND YOUR OWN BUSINESS \nSO YOU SEE THE DIFFERENCE\nPEOPLE WHO LOSE CONSCIOUSNESS HAVE BRAIN BUT THEIR MIND STOPPED WORKING.\nBRAIN IS LOCATED IN HEAD BUT MIND IS REALATED TO HEART TOO
401951
A coma is a deep state of unconsciousness, during which an individual is not able to react to their environment. Someone in a coma cannot respond to any form of stimulation whatsoever. Coma can be caused by an underlying illness, or it can result from head trauma. A comatose person is still very much alive, but he or she is not simply asleep. The brain wave activity in a comatose person is very different from that of a sleeping person; you can wake up a sleeping person, you can't wake a person in a coma. A coma usually does not last for more than a few weeks. Many people recover their full physical and mental functioning when they emerge from a coma. Others require various forms of therapy to recover as much functioning as possible. Some patients never recover anything but very basic body functions.\n\nSometimes, following a coma, a person may enter what is known as a persistent vegetative state; patients in persistent vegetative state have lost all cognitive neurological function but are still able to breathe and may exhibit various spontaneous movements. They may even be awake and appear to be normal but, because the cognitive part of their brain no longer functions, they are not able to respond to their environment. A vegetative state can last for years.\n\nThere are various other terms, in addition to coma and vegetative state, that are used to describe varying levels of unconsciousness and a person's ability to respond to stimuli. These include stupor, in which a person is unconscious but will eventually respond to repeated, vigorous stimulation; and obtundation and lethargy, which are used to describe a person who is not entirely unconscious but does not respond to stimuli.\n\nUsually, coma and other altered states of unconsciousness are considered neurological emergencies, and actions need to be taken quickly to avoid permanent damage.\n\nThe Human Brain\nThe human brain is made up of three basic parts: the cerebrum, the cerebellum, and the brainstem. The cerebrum is the largest part of the brain and makes up about 85% of the brain's total weight. It's divided into two hemispheres, the cerebral hemispheres, one on each side of the head. The cerebrum is where all of the body's most complicated mental and sensory functions are controlled - intelligence, reasoning, memory, emotions, vision, our ability to feel things, etc. The cerebellum is a smaller part of the brain that lies behind the cerebrum. It plays an essential role in coordination, posture and balance. The brainstem is the stemlike part of the brain that connects the cerebral hemispheres to the spinal cord and is responsible for controlling many basic bodily functions, such as breathing, blood pressure, and being awake and alert.\n\nUnconsciousness\nAs with most mental processes that occur in the brain, the biology of consciousness - also called arousal - is very complicated and not well understood. There are many tissues located deep within the brain that play a role in how conscious and alert a person is. Researchers believe that one of the important physiological processes that keeps a person conscious is the transfer, or neurotransmission, of chemical signals from the brainstem to the cerebral hemispheres of the brain. This continuous neurotransmission needs to be happening in order for a person to be aware of their environment. Abnormalities that interrupt it can lead to coma or other states of unconsciousness.\n\nAbnormalities that can cause coma include injury or damage to the brain that leads to swelling (edema) in the brain, which results in an increased intracranial pressure (pressure within the skull). Increased pressure, whether it is localized in one particular spot or spread over the whole brain, decreases the flow of blood and can lead to unconsciousness. Injury or damage to the brain can also cause some areas of the brain to shift within the skull and exert pressure on surrounding tissues and structures, including blood vessels
1020656
People who have had near death experiences no that consciousness continues after we are clinically dead. Many people have reported floating above their dead body on the operating table and being able to give clear details of what was going on around them, like what the doctors where doing and saying.\n\nWe lived as conscious beings before we obtained physical bodies here on earth and we will continue to live as conscious beings after our physical body dies.
1082420
Because heart pumps oxygenated blood to the various parts of the body. When the heart stops beating the body does not get its dose of oxygen.
443099
no matter where in the brain a stroke occurs part of the brain dies.  With the cerebellum conducting much of the involuntary actions of the body a stroke could have no effect, but at the same time it could be as significnat as shutting down the heart or stopping the resporatory cycle if that part of the cerebellum dies during the stroke
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.
179080
This is a very interesting question.  I wonder if there is a scientific answer for this.  Let me google it.....\n\nhttp://www.msnbc.msn.com/id/11023208/  is a great link for reading about the connection between the heart and the brain.  This was a good question and I learned alot.  Thanks.
1057133
A person can be declared dead in an emergency room when they are in cardiac arrest and cannot be resuscitated, or if they've been asystolic for more than six minutes and revival would likely result in a vegetative state.\n\nDeath can also be declared by other emergency personnel when specific requirements are met. Levidity, rigor mortis, decapitations, etc.
94607
It's not possible because "dead" means "brain dead".\n\nIf you mean any other standard of death then we bring people back from the dead all the time. It probably happens 10-20 times a day in any major hospital.\n\n\nBrain death can't be reversed the way you describe because the individual is the brain. \n\nIf we replaced your 'unfunctional' brain with someone else's , and by some kind of treatment brought the rest of the body back to life YOU as an individual would still be just as dead. All your memories and thoghts and feeling would have ceased to exist. You would be dead because you are your brian, and your brain is dead. Swapping your dead brain for a different functioning brain won't solve that problem.
1027259
Hello Summerspirit,\n\nThanks for your question. I think this question deserved a better reponse than what it has received till now. Anyways, I'll try to compensate: \n\nFirst of all, neurons don't usually die at all. The neurons are the cells with the least regenerative powers in our body. Once killed, they cannot be replaced! But, as we grow older, some wear and tear is unavoidable and brain cells too are no exception to the wear and tear of ageing. \n\nStill, the brain cells are the last to die in our bodies as they are kept well oxygenated by an abundant blood supply.\n\nNow, the neuroglia cells that support the neurons are not as sustainable as the neurons and thus, are subject to regular wear and tear. So, there must be a path for them and other metabolic wastes to leave the brain, right? \n\nOur brain as opposed to popular conception is not a lump of matter floating in blood. It is floating alright but, not directly in blood. The brain floats in a colorless, transparent, plasma-like fluid called Cerebro-Spinal Fluid or CSF. The fluid provides a one way traffic from the cavities and membranes of the brain to the vein carrying used blood.\n\nSo, the CSF takes the dead brain-cells and flows towards a blood stream, then the waste matter is transferred to the blood.\n\nThe blood then takes the stuff to the kidneys which is known as the sieve of the human body. Kidney filters the metabolic waste from the blood to urine from where it is passed from the body.\n\nHope it helped to keep your summer spirit alive! Bye!
78046
the one of brain's function in human physiology is that on the certain segment of brain controls heart rate. That means brain can order the heart to keep on pump in order to stay alive. \n\nWith each beat, the heart continuously communicates with the brain and body via the nervous system, hormonal system, bioelectromagnetic interactions, and other pathways.
46169
When a couple has been together for a really long time, lets say 40-50 years+ and they had a happy marriage and then one of the spouse passes away, and the other spouse doesn't get over their grieving,or they lose hope, or they don't have any determination to go on living, their can body shut down and they can end up getting sick or die from a "broken heart".They can die within days,weeks,or a couple of years. Because people need love like they need food and water. Just like babies. If they are not held or nurtured, they can die or they get sick or their body delays growth. But anyway, if you are brave enough you can go down to the cemetary and you can look at the headstones of couples and the calculate how far apart they died.
814920
You will find a good explanation on this site.\nhttp://en.wikipedia.org/wiki/Brain_death