Biology 103
2002 First Paper
On Serendip

It seems that everything around us is coming to an end. Walk down the aisle of a grocery and you'll see cans of oranges with expiration dates stamped on the side to remind us of the transient nature of grocery goods. A CD doesn't play forever and a candle always burns out. Even fun has to end for wild nights of hedonism are bound to once again turn into blue Mondays. So, if everything around us is reaching its grand finale, where does biology, the study of life, end?

Before advances in modern science made it possible to restore broken hearts and weary lungs to their original operative states, death was easy to notice. When the beat of the heart stopped, one was considered dead. Now, with technology developed to resurrect the dying, the once clean-cut line between life and death has been dulled, only to incite a fury of discussion (3). This debatable issue exists on a variety of levels for it is a grouping of diverse "philosophical, theological and scientific ideas about what is essential to embodied human existence"(2). However, before delving into a discussion of death, it is first important to think about what constitutes life.

Simply put our bodies are made up of a collection of cells. If one of these cells were to be extracted from a multicultural organism and placed in a solution with the appropriate nutrients, it would endure with no great trouble. It would keep on performing the basic metabolic processes considered necessary to life; taking in nutrients, breaking them down to create energy, then using that energy to divide, expel wastes and further develop. This sort of life could be considered metabolic. The next step up would be the level of tissues and growth. These are basically collections of cells that are grouped into carrying out the same functions as described above. Extracting muscle tissue, which is composed of cells whose purpose is to contract upon correct stimulation, placing it in a supporting solution and artificially energizing it will cause it to contract. This sort of life can be considered to be organic life. Further grouping individual organs together, as in our own bodies, adds another plane of life to the framework. These examples illustrate the view that life is narrowly biological in nature and would further suggest the cause of death to be the malfunction of particular organizational structures. To state that the cessation of human life is a clear-cut biomedical process would be to refute the idea of consciousness; the soul, the spirit, the mind (3).

"I think, therefore I am" - Rene Descartes

Released in 1981, the Uniform Determination of Death Act (UDDA) was a landmark statement that specified two alternative criteria for determining death.

An individual who has sustained either (1) irreversible cessation of circulatory and respiratory functions, or (2) irreversible cessation of all functions of the entire brain, including the brain stem, is dead. A determination of death must be made in accordance with accepted medical standards (5).

The UDDA then recognizes that death can be determined by the traditional cardiopulmonary criteria, yet also authorizes brain death to be declared for patients who fail to meet traditional criteria because cardiopulmonary functions are artificially maintained. Due to the UDDA's adoption of either cardiopulmonary or neurological criteria for the determination of death, this act has been carped by many as being confused. For both neurological and cardiopulmonary criteria can serve as signals to show an organism's capacity for life has been permanently lost. Since it is respiration and cardiac, not brain, activity that can been artificially maintained, many claim that neurological criteria provide direct evidence of death, while cardiopulmonary criteria only provide indirect evidence. In the event that respiration and cardiac activity are artificially sustained, neurological criteria must be used to certify someone as dead (1).

Medical advances have made it possible to transplant organs and tissues, and the expansion of technological methods to artificially sustain respiratory and circulatory functions have made it crucial to reconsider our understanding of death and have encouraged the adoption of brain-related criteria for death. When somebody passes away it is not the loss of the physiological function that is missed, but the person that was sustained by such functions. The brain contains the physiological centers responsible for integrating the functions of various other organ systems and tissues of the body, so that it is the death of the brain that results in the loss of integrated functioning (5). Consciousness and cognition reside in the cerebral portion of the brain, and by focusing on this advocates of brain-based criteria do not bash the traditional views of death based on cardiopulmonary criteria, rather they tend to see the profound difference between conceiving human life "as a heart-centered reality and as a brain-centered reality" (2).

However advocates of brain-standard criteria usually tend to slip away into two schools of thought, "whole-brain" versus "higher-brain" criteria for a standard of death (4). According to advocates of whole brain criteria, a person is brain dead only when the entire brain, including the stem, is dead. In application a few problems do arise, however, since patients who meet the standard clinical tests for brain death may still maintain some brain function, such as the secretion of neurohormones, or coordinated activity within isolated nets of neurons. This has driven some to further refine neurological criteria for brain death based upon functional differences between the different parts of the brain. The brain stem is the elemental constituent that supports most vegetative functions essential for life - regulation of wake-sleep cycles, respiration, swallowing. "When the brain stem ceases to function, the person loses capacity for spontaneous circulatory and respiratory function as well as the capacity for consciousness" (2). The issue of concern between advocates of whole-brain and brain stem death criteria is essentially which brain structures and functions must be lost in order to certify that the body no longer has power over the capacity for spontaneous regulation of vital processes. What the two measures have in common though is the fact that they both reflect the concept of death as a loss of integrated functioning of the organism as a whole, body and soul.

The higher brain formulation proves tricky though when placing it in practicality. This is most easily illustrated when considering higher brain death in the context of patients with a condition referred to as a "persistent vegetative state"(PVS). In such patients, all higher brain functions are lost, however brain stem functions remain largely intact. With medical care, such as respirators and artificial nutrition, people in a PVS can live for many years (1). If brain death criterion for death is employed, such patients would be considered dead. In situations such as this careful concern needs to be given in order to draw a distinction between the questions of when it is morally permissible to withhold treatments and allow a patient to die, and when it is right to declare a patient dead. In the end, one's response to brain-death standards depends both on ethical judgments and one's degree of trust in the medical profession itself.

References

1) Brain Death and Technological Change: Personal Identity, Neural Prostheses and Uploading. , James J. Hughes, 1995.

2) The Determination of Death , May, 1997.

3 Definition of and Criterion for Determining Death , Igor Jadrovski.

4 Report from the national institute of philosophy & public policy , Consciousness, and the Definition of Death, 1998.

5) Neurology: Brain Death Criteria , Carlos Eduardo Reis


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