Sleep and consciousness - Essay Example

Comments (0) Cite this document
Laureys: Death, unconsciousness and the brain. This article reviews the how definitions of death have changed with medical progress and understanding of the critical role of the brain in meaningful life.
There have been many definitions proposed for the term death with most…
Download full paperFile format: .doc, available for editing
GRAB THE BEST PAPER94.2% of users find it useful
Sleep and consciousness
Read TextPreview

Extract of sample "Sleep and consciousness"

Please answer the following questions based on the assigned readings. If you use additional sources, please cite these Laureys: Death, unconsciousness and the brain. This article reviews the how definitions of death have changed with medical progress and understanding of the critical role of the brain in meaningful life.
a) What are different biological definitions of death? What criteria have been used to define death?
There have been many definitions proposed for the term death with most of them centered upon the functioning of the brain like irreversible absence of brain function or irreversible coma, complete irreversible loss of brain stem function, irreversible loss of the capacity for consciousness and interaction also referred to as being in a vegetative state. Some scientist and philosophers have defined death based on the functioning of the circulatory system as a state when there is irreversible cessation of circulation. Since different definitions have been given to explain death, there are several criteria’s that are used to determine death. In case of whole brain damage complete cessation of all clinical functions is a major criterion which could be demonstrated as coma. Similarly irreversible cessation of brainstem functions with absence of brainstem reflexes. Other criteria include absence of any other confounding factors, absence of motor responses, and apnoea. Neurological and cardiopulmonary tests are done to ascertain the death of an individual. In the neurological tests irretrievable brain stem function is determined, while in the cardiopulmonary test irretrievable absence of heart beat and breathing are determined. However, after much debate it has been decided that the cardiopulmonary criteria of death which declares that the heart will not auto-resuscitate and which occurs first is a sufficient enough criterion to declare that a person is dead as it might take some time for the neurological criteria to occur.
b) How do brain death and vegetative state differ? Consider a) behavioral, respiratory (“apnoea”means lack of breathing), b) damage to specific brain structures, and c) brain activity (e.g. EEG, fMRI, PET).
The major criterion for a person to be declared brain dead is presence of coma characterized by irreversible brain damage, while in the case of vegetative state; a person is awake but totally unaware of the surroundings. Such a vegetative state can be partially or totally reversed. However persistent vegetative state cannot be reversed. Brain death can be diagnosed more quickly that irreversible vegetative state as it may take any where between 3 to 12 months depending on the extent of injury to the brain to ascertain vegetative state. Brain dead patients require artificial ventilation but those in the vegetative state require the same only in acute stages and otherwise they can breathe without any assistance. The brainstem and hypothalamus are well preserved in the vegetative state and hence these patients show significant motor activity with movement of specific parts such as the trunks, limbs and head but they are not well coordinated or might happen without any purpose. These movements are highly instinctive and might be in response to any external stimuli. They also exhibit facial expressions. In case of brain dead patients, due to damage of the brain stem the body movements are restricted and occur only as a result of any residual activity in the spine or other areas and are not in response to any external stimuli. They also do not show any kind of facial expression. Various imaging studies such as Doppler sonography and positron emission tomography can be used to show the absence of cerebral blood flow and neuronal activities in the brain of brain dead individuals. There is also a complete absence in EEG activities and a total lack of conduction through the brain which is determined by somatosensory potentials given to the individuals. However in the vegetative state there is no complete absence of the above activities as there is considerable amount of cerebral blood flow and metabolism. The EEG in this case is slow and mostly of very low voltage. Presence of cortical potentials can be observed in the vegetative state.
c) If a person is in a vegetative state, how long should medical treatment be maintained before a person can be removed from life support? Or, should person never be removed from life support without prior consent?
Patients in the vegetative state generally do not require artificial ventilation or cardiac support unless they are in acute condition. They need to be provided with adequate hydration and nutrition. Stopping the nutrition supply to the individual should be based on established studies carried out on the patient that declares the patient is in an irreversible vegetative state. This has a lot of ethical considerations and only when there is adequate proof that the patient will no longer benefit from medical treatment administered should life support systems be removed. According to research that has been conducted the chances of recovery after 3 months and 12 months for non-traumatic and traumatic injuries are very less. If the individual does not show any signs of improvement the immediate relatives should be consulted to decide upon the future course of action. After obtaining their consent the hydration and nutritive support can be stopped which can lead to death anywhere between 10 to 14 days. Patients who previously express their desire to undergo euthanasia can be subjected to the same as this has been legalized in some countries.
d) Who should pay for maintaining people in a vegetative state?
Since the decision to maintain the individual in life support systems is done by the relatives they must bear the expenses for prolonging of the medical treatment.
2. Mahowald & Schenck: Insights from human sleep disorders.
The authors describe four categories of sleep disorders: hypersomnia, insomnia, circadian rhythm disorders, and parasomnias. In a brief essay:
a) Define each category of sleep disorder;
While there are about 100 disorders related to sleep or wake, most of them fall under four broad categories: hypersomnia, insomnia, circadian rhythm disorders and parasomnias. Hypersomnia is characterized by excessive sleep during daytime which could be due to either social or economic reasons or sleep disorders such as obstructive sleep apnoea and narcolepsy. Insomnia could be defined as the inability to get a sound and sufficient sleep which in most cases is due to the presence of an underlying medical or psychological problem. In the case of circadian rhythm disorders, humans have a routine pattern of activity often referred to as the biological clock and rest based on the light and dark cycle, but when this routine pattern is interrupted due to medical or environmental factors it results in abnormal timing of sleeping pattern. However these people do not experience any disturbance once they fall asleep. Parasomnia is a sleep disorder characterized by unpleasant and unnatural behavior while asleep mostly due to the presence of any psychological problems.
b) Give a specific example (e.g. narcolepsy as an example of hypersomnia) and describe the 1) clinical characteristics, 2) prevalence and risk factors, 3) biological mechanisms and causes (if known) and 4) treatment.
The major clinical characteristics associated with narcolepsy include: tendency to fall asleep during a period of no activity in the day, experience of sudden muscular weakness while emotional, feeling drowsy before onset of sleep and tendency to remain in a semiconscious state while awakening, hallucinating, sleep paralysis and inability to have a sound sleep during the night. The occurrence of narcolepsy is rare affecting 1 in 2000 individuals. While the initial causative factors for narcolepsy was considered to be psychiatric continued research have revealed that narcolepsy occurs due to disorders in the nervous system of the individual. The genetic components associated with the disease have been identified to be HLA DR2/DQ1 and DQ6. However scientists have maintained that inheriting the genetic component alone cannot cause the disease given its rare occurrence rate. Another significant factor that has been identified is the absence of secretion of a neuropeptide, Hypocretin-1, by cells in the hypothalamus. The non-secretion of this neuropepetide does not occur in any other condition thus ascertaining its link with this disorder. There are medications available for the treatment of this disorder and since the discovery of its association hypocretin-1 injections have been tested in animals which have caused significant reduction in the occurrence of cataplexy and have normalized the sleep/wake behavior in these animals.
1. Laureys, Steven. “Death, unconsciousness and the brain.” Nature Reviews Neuroscience 6 (2005): 899-909.
2. Mahowald M.W and C. H. Schenck. “Insights from studying Human Sleep Disorders.” Nature 437 (2005): 1279-1285. Read More
Cite this document
  • APA
  • MLA
(“Sleep and consciousness Essay Example | Topics and Well Written Essays - 500 words”, n.d.)
Sleep and consciousness Essay Example | Topics and Well Written Essays - 500 words. Retrieved from
(Sleep and Consciousness Essay Example | Topics and Well Written Essays - 500 Words)
Sleep and Consciousness Essay Example | Topics and Well Written Essays - 500 Words.
“Sleep and Consciousness Essay Example | Topics and Well Written Essays - 500 Words”, n.d.
  • Cited: 0 times
Comments (0)
Click to create a comment or rate a document

CHECK THESE SAMPLES OF Sleep and consciousness


...Sleep Part I Sleep is an expression referring to that regular situation that has behavior change that has thecharacteristics of ease in reversibility, relative quiescence, as well as significant rise in the thresholds of response. (National Research Council (US), et al, 1987p9) Scientists are yet to unravel exactly why we sleep. As a matter of fact humans can survive for a longer duration without eating than without sleeping. Birds, animals, as well as reptiles alike sleep. According to scientists these mentioned theories discuss why humans sleep. Sleep might be a way through which brain recharging is achieved. Also,...
2 Pages(500 words)Essay


...?Sleep Sleep is an important part of the living process which every human being goes through. It comes about as a period of rest and recovery from the dire demands of wakefulness. This is essentially a state of unconsciousness where the individual does not know about the worldly affairs that surround his entirety. There are states of partial consciousness which can be revoked by stimulation. A person spends about one-third of his life whilst sleeping. Sleep is significant for every person because it recharges his body and mind. It makes him fresh because it is a crucial ingredient that goes into delivering work regimes on an out and out basis. There are...
3 Pages(750 words)Essay

Sleep and Sleep Disorder

...Sleep and Sleep Disorder Introduction Sleep is a vital component in human life. Some people fail to have enough sleep because of several factors that include health issues like sickness and stress. People having difficulties in sleeping are said to have sleep disorders. Doctors and psychologists advice people to get enough sleep as much as possible to boost their health while going about their activities normally. Each individual experience sleep disorders at different rates depending on age, sex and their daily activities together with the external factors. Scientists cannot generalize the causes of...
5 Pages(1250 words)Research Paper


...How Do We Know The relationship between thought and consciousness has intrigued human beings from the times of the earliest civilisations and forms the foundation of self-consciousness. Socrates expressed the unsettling idea that the only thing we can certainly know is that we know nothing. This was unsettling because our relationship to the world is determined by our knowledge of it: not being able to know anything has disastrous implications for our ability to act. Altered states of consciousness: for example dreams and trances and the consciousness of children or the insane: are disturbing because 1) these forms of consciousness arise from the same...
5 Pages(1250 words)Essay

Consciousness & Coma

...of the conscious human mind. The psychiatrists also deal with this joint study of consciousness and coma. Psychologists are interpreting these in various ways. Both the terms define opposite conditions of mind but they are inter-related.  Coma is the change from consciousness to unconsciousness. Consciousness varies in degrees- crude consciousness, phenomenal consciousness and access consciousness.  Crude consciousness is the alertness and confines to normal sleep and wake cycle. Phenomenal consciousness is the awareness of the mind. It deals with the ability of the brain to deal with...
8 Pages(2000 words)Research Paper

Legal Consciousness

...Legal Consciousness Task: Legal Consciousness Introduction Teachers occasionally find themselves in legal dilemmas, which render them vulnerable to legal consequences. Parkay & Stanford (2007) observe that the worst time in a teacher’s life is never in the classroom, but while in duty. This indicates that teaching is a sensitive career that demands one to maintain a legal conscious mind. As such, every teacher should be knowledgeable on the regulations and policies governing his/her activities to avoid unsuitable consequences. Therefore, this essay presents my experience on the Texas School of Law (TSL) and Education System, thus, presenting an informative piece that explains how teachers need to observe...
3 Pages(750 words)Essay


... Psychology 19 July Sleep Introduction Sleep is essential to life and health, but people are more inclined to deprive themselves of sleep than of water, food, and air. The body demands for sleep can be resisted or even ignored more easily than hunger, thirst, and the need for air. An average person needs one hour of sleep for every two hours of wakefulness (Honeycutt and Milliken 66). 2. Human Sleep Cycle Numerous body functions involve specific rhythms or cycles known as biorhythms. The need to sleep is a human body want. This need is regulated by the brain circadian pacemaker. The circadian pacemaker is influenced by the earth’s electromagnetic fields. As the sun sinks in the sky, it follows that daylight shifts to dusk... , and then into...
2 Pages(500 words)Essay

Diversity Consciousness

...Diversity Consciousness: Introduction Diversity consciousness brings in a perception that is largely not present in work places or learning courses. In many cases, diversity issues are like an afterthought or treated lightly. A general assumption is that individuals learn of diversity in their own way. Unfortunately, humans may comprehend it to mean that it does not contribute to their success or education (Bucher, 2010). This interpretation is unacceptable in many studies in business and education fields. This paper depicts reasons for diversity consciousness. Diversity conscious is learner oriented, success oriented, focuses on empowerment and personal growth, it is research grounded...
3 Pages(750 words)Essay


...principles of science (Searle, 2013); 6. Consciousness begins when we wake up from a dreamless sleep and ends when we go back to another dreamless sleep or we die. Dreams are part of consciousness; 7. Consciousness remains with the person till three minutes after his heart stops beating even when the brain stops functioning 20 to 30 seconds after the heart stops (AFP, 2014) 8. Consciousness is real because as Descartes pointed out we think therefore we are; 9. Consciousness exists as a unified conscious field and the experiences that we achieve through our consciousness are casual in nature (Chalmers,...
3 Pages(750 words)Essay


...Sleep How relevant is sleep to your PERSONAL Lifestyle? Sleep is a critical aspect of humanity. It helps in rejuvenating one’s mental and physical energy for undertaking daily activities. My personal lifestyle as a student emphasizes allocation of more time to study and partial leisure before sleeping. I believe in taking about six hours of sleep to freshen up my mind, get physical energy by eliminating fatigue. For a learner like myself, six hours of sleeping makes me wake up with significant morale to face the next day activities with ease. 2. Are you getting enough? I do get enough sleep by allocating six hours. This...
1 Pages(250 words)Essay
sponsored ads
We use cookies to create the best experience for you. Keep on browsing if you are OK with that, or find out how to manage cookies.

Let us find you another Essay on topic Sleep and consciousness for FREE!

Contact Us