Life and death?

Question

How can we define life and death? what makes someting 'live' and what makes it 'die' ?

Answer 1

Most definitions of "life" involve some sort of criteria like "the ability to respond to stimuli", "the ability to chemically metabolize substrate for energy", and "the ability to reproduce". People are willing to bend those definitions when they want to make a case that non-cellular entities such as virus particles are alive, but this is really just word play. Things are what they are, and we can paint them with words but it doesn't change a thing. The real questions about life and death are about human beings, about when we become alive in the first place and when we are no longer alive, at the end. Unless we want to get into an argument with the religious community about abortion, we should probably leave the first question alone! However, there is plenty to talk about in the second case, where life ends and how we determine this.

Life and death are specifically defined when you're talking about human beings. There are all kinds of reasons why these terms need to be strictly defined, but thats a huge topic that is too big to fit here. The CLINICAL DETERMINATION of death, for human beings, involves the loss of the pulse. Clinical determinations are made by physical exam. A person who has no pulse by physical exam, is dead.

However, as Billy Crystal said in The Princess Bride (one of my all time favorite movies), "He's not dead, he's only MOSTLY dead, and MOSTLY dead means PARTIALLY ALIVE!" People who lose their pulses can sometimes be recovered. We do, in fact, bring dead people back to life.

When a person has a witnessed loss of pulse, which means that they get an emergency response instantly, Rescue efforts including CPR and emergency defibrillation (electric shocks) are successful at restoring pulse and blood pressure about 10% of the time. That's pretty lousy odds, to be sure, but it's pretty good if you're one of those 10%-ers!

There is another sticky situation when it comes to defining death. In some cases, people will have massive brain injury but the heart will continue to function.

A great example is when that person has a heart attack in a restauraunt, and bystanders immediately administer CPR, but it takes them 20 minutes to get the heart restarted and during that time, the brain goes without oxygen far too long to survive. The heart restarts but the brain is oatmeal!

There is a recognized phenomenon of BRAIN DEATH. Brain death is different from clinical death as defined by lack of heartbeat/pulse. In order to determine that someone is brain dead, we have to prove that all functions of the brain have stopped. There are several criteria that must be met.

First of all, someone who MIGHT be brain dead is bad-off enough that they're not breathing on their own. In order to last more than a few minutes, these patients would have been placed on a ventilator (breathing machine) in a hospital ICU. They are not moving and the pupils don't react to light anymore. The question arises, "Is this patient brain dead?" and an evaluation follows.

First, the ventilator is stopped and the patient is observed for any signs of even the most feeble effort to breathe. Next, the ventilator is restarted, and efforts are made to find any sign of primitive brain stem function. Pupil and corneal reflexes are checked, and cold water is squirted into each ear (this test will show eye movement toward the side getting squirted due to a vestibular reflex). If there is no sign of breathing or brain stem function, a scan of the blood flow to the brain will often show that the whole brain has no blood flow, and is completely dead. That person has died. The heart continues to beat only because the machines are helping to support the dead body's remaining physiologic functions.

The bad news is that there is nothing more that can be done. The good news is that there is a possibility that this person, if they have agreed to donate organs, may yet save other people's lives!

At the cellular level, the brain dead person's tissues continue to be viable. The metabolism of substrate continues, the potential to react to the appropriate stimuli continues to be uninterupted. However, I will not call this "life" because the property of "life" for a human being includes the ability to function as an independent entity, and without the central nervous system this is impossible. The individual organs are not "alive" or "dead" but since they are still functional, they can be transplanted into a sick person and will continue to function, or at least thats the general idea!

Answer 2

Life. Noun. "The condition that distinguishes organisms from inorganic objects and dead organisms, being manifested by growth through metabolism, reproduction, and the power of adaptation to environment through changes originating internally."

Death. Noun. "The act of dying; the end of life; the total and permanent cessation of all the vital functions of an organism."

If you want my personal, philosophical answer... Anything that dies is alive ;-) Actually... anything that has living cells; that needs biological nourishment. However, whether it's a sentient being, or deserves certain 'rights' is another matter. A plant is alive; should someone go to jail for killing it? Should it be legal to kill a plant?

Answer 3

LIFE
Life is the characteristic state of organisms. Properties common to terrestrial organisms (plants, animals, fungi, protists and bacteria) are that they are cellular, carbon-and-water-based with complex organization, having a metabolism, a capacity to grow, respond to stimuli, reproduce and—through natural selection—adapt.

An entity with the above properties is considered to be organic life. However, not every definition of life considers all of these properties to be essential. For example, the capacity for descent with modification is often taken as the only essential property of life. This definition notably includes viruses, which do not qualify under narrower definitions as they are acellular and do not metabolise. Broader definitions of life may also include theoretical non-carbon-based life and other alternative biology.

The entire Earth contains about 75 billion tons of biomass (life), which lives within various environments within the biosphere.

DEATH
Death is the full cessation of vital functions in the biological life. This article discusses death in the biological sense of the term, and its place in various cultures.

Answer 4

Well death is the end of life; the total and permanent cessation of all the vital functions of an organism. And life is the condition that distinguishes organisms from inorganic objects and dead organisms, being manifested by growth through metabolism, reproduction, and the power of adaptation to environment through changes originating internally. Does that make sense?

Answer 5

Life is extremely hard to define, and so far no one's come up with a very good definition. As for dying, something dies if it is alive and then becomes not alive. So the definition of death is based on the definition of life.

Answer 6

i'm somewhat perplexed. life earlier start is interior the womb for 9 months. yet life after demise is in easy terms the actual undeniable reality that the body dies little through little, so as that hair and fingernails proceed to develop for a couple of minutes. If we are saying life earlier theory, then the parallel is closer. yet what i quite imagine you advise isn't life, yet knowledge or knowledge. there is not any function without the shape to attempt this function. for this reason, there should be no knowledge earlier or after there's a mind to do it with.

Answer 7

Life is the emergent property of highly complex chemical reactions. This includes adaption to environment, reproduction, respond to stimuli, regulation, growth, energy transfer etc. Life can exist at a unicellular level (such as Bacteria etc) and multicellular level (Humans etc).

Death, is lack of the characteristic chemical reactions mentioned above (enregy transfer etc). It is the END OF LIFE. Please contact me for further information, I cannot fully explain it over Yahoo Answers.

Answer 8

Death is all a part of life if you think about all you really have to do in life is die. That is the one thing that you cannot escape.

Answer 9

Life is
L I F E
and Death is
D E A T H

Answer 10

Ever the best Scientists are divided on this. For example are Viruses alive? Are Prions? Some think so, some don't.