...Describe and evaluate research into circadian rhythms (8+16) Research into circadian rhythms has assessed the effects of isolating participants from external time cues (exogenous zeitgebers) on our 24 hour cycles, and suggesting that an internal body clock (endogenous pacemaker) creates a free running sleep/wake cycle rhythm of 25 hours. Siffre (1975) * Case study of his own experiences in an underground cave for 2 months. Without any exogenous zeitgebers such as light or cues to guide him, his sleep/wake cycle generally adjusted to a 25 hour cycle, though sometimes changing dramatically up to 48 hours. Aschoff and Weaver (1976) * Designed a temporal isolation study by placing participants in an underground ww2 bunker without an environmental or time cues. * They found that the free running cycle persisted with a sleep wake cycle of 25 hours, sometimes increasing to 29. Weakness into research of circadian rhythms * Lack internal validity. * They removed natural light sources, artificial light from torches and cameras have been shown to reset the endogenous rhythms, thus interfering as an extraneous variable. Exemplified through Czeisler et al (1999) * Altered participants’ circadian rhythms down to 22 hours and up to 28 only using dim lighting to alter his release of melatonin from the pineal gland. * Findings do not reflect true isolation and have lower internal validity, so his rhythm may not have adjusted so well if he had been truly...
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...The Consequences of Disrupting Biological Rhythms All living organisms experience rhythmic changes, which tend to coincide with seasonal or daily environmental changes. These rhythms are known as biological rhythms, which include circadian, ultradian and infradian types. All biological rhythms are controlled by two different factors - internally (endogenous) through nature, and externally (exogenous) through nurture. Most organisms have internal biological clocks, called endogenous pacemakers. The main endogenous pacemaker in circadian rhythms is the suprachiasmatic nucleus (SCN), a small bundle of nerves in the hypothalamus, as suggested by Morgan (1995), and Kalat (1998). Kalat suggested that low levels of light lead to an electrical stimulant, which activates the pineal gland in the SCN, located in the centre of the brain, to secrete a hormone called melatonin, which causes sleepiness. Its production of melatonin varies with periods of light and darkness in the environment, and it obtains this information about light in the environment by means of nerve pathways originating in the eyes. Therefore the main exogenous zeitgeber ('time-giver') that controls circadian rhythms is therefore light. Research that suggests the SCN is the main endogenous factor for circadian rhythms comes from Morgan in 1995. His aim was to determine whether the SCN in hamsters is linked to the dissappearance of their circadian rhythms. He removed the SCN from hamsters and transplanted an...
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...Institute Circadian rhythms are regular changes in mental and physical characteristics that occur in the course of a day (circadian is Latin for "around a day"). Most circadian rhythms are controlled by the body's biological "clock." This clock, called the suprachiasmatic nucleus or SCN, a pair of pinhead-sized brain structures that together contain about 20,000 neurons. The SCN rests in a part of the brain called the hypothalamus, just above the point where the optic nerves cross. Light that reaches photoreceptors in the retina (tissue at the back of the eye) creates signals that travel along the optic nerve to the SCN. Signals from the SCN travel to several brain regions, including the pineal gland, which responds to light-induced signals by switching off production of the hormone melatonin. The body's level of melatonin normally increases after darkness falls, making people feel drowsy. The SCN is synchronized with the sleep/wake cycle, including body temperature, hormone secretion, urine production, and changes in blood pressure. Sunlight or other bright lights can reset the SCN, our biological cycles normally follow the 24-hour cycle of the sun, rather than our innate cycle. Circadian rhythms can be affected to some degree by almost any kind of external time cue, such as the beeping of your alarm clock, the clatter of a garbage truck, or the timing of your meals. Scientists call external time cues zeitgebers (German for "time givers"). Circadian rhythms is the sleep/wake...
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...Class: BBA-8 Circadian Rhythms as a basis of mood disorder, in particular bipolar disorder. Introduction: The complex structure and the functions of the human body has been a subject of study by a lot of individuals since a very long time. The curiosity of the human being supporting it, further aids in discovering the secrets hidden behind the way a human being is. Biological rhythms or circadian rhythms also make up one of the hidden secrets for the functions of the human beings and scheduling of various tasks. The terms Circadian is derived from Latin word Circa, “around” or “about” and diem or dies “day” meaning literally “about a day” or “around a day”. This circadian rhythm is already built in the complex human body but is regulated by external factors known as “zeitgebers”. The primary or the most important zeitgebers is ‘light’ which helps human automatically start a particular process in one’s life and controls various cycles at regular intervals. This may include sleep/wake cycle, eating habits, seasonal affective disorder (SAD) or bipolar disorder. Scientists have long been researching the effects of disturbance of circadian rhythms and its consequences on the life of a human being. This paper also considers the facts that have been established in this area to identify and discuss the process undergoing in a human being and its complexities with a particular reference to circadian rhythms and bipolar disorder, its causes and how shall...
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...All living beings possess a built-in, biological alarm clock. This clock is responsible for innumerable bodily functions that are performed during various stages of a day/week/month/year. Examples include bowel movement, digestion, hormone production, menstrual cycle and migration (among birds/animals), to name a few. All these functions follow a particular cyclical pattern. When this process recurs annually, it is known as a circannual rhythm. Similarly, when this process recurs on a daily basis, it is known as a circadian rhythm. The word circadian comes from the Latin words ‘circa diem’, meaning about a day. Circadian rhythms are controlled by a biological clock within our brain. This section of brain is called the 'suprachiasmatic nucleus' (SCN). Signals produced by the SCN travel to different sections of the brain, thus stimulating various functions, such as body temperature, hormone secretion, changes in blood pressure, etc. There are numerous external factors as well, that regulate a circadian rhythm among human beings. These external factors are called zeitgebers (Hawkins & Orlady, 1993). Most common zeitgebers are light and temperature. Others include meal times, various social and physical activities. The most common circadian rhythm known to mankind is the sleep cycle. Sleep is an extremely important physiological phenomenon, during which our body heals and recuperates. Let us begin with understanding what sleep is, and what are the various sleep patterns. Sleep...
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...knowledge of biological rhythms and their impacts disscuss the impact of these demands. Shift work is a work pattern that falls outside of the normal 9-5 working hours. Shift hours came into place firstly in hospitals. This was because the patients needed round the clock care. Another place where shift work came into place was in factories. However even though there are advantages to this type of work there are negatives too, one of these is that there are major disruptions to the employee’s sleep patterns. Most sleep is needed during the times of 2-4 am. This is when most shift workers will struggle to get through their shift. Another reason why it affects them is because it changes the circadian rhythm. The circadian rhythm is a 24hour rhythm which a person recognises and it tells the person to sleep when it is dark and to wake when it is light. This is affected by shift work because they spend most their time under artificial light. Another reason why they struggle is because when the lights go off they need to make sure that they stay awake in case there us an emergency of some kind. Employees can sometimes be offered a night shift where they can have a couple of hours sleep, however they opt out of this type of contact because it pays less than what a night shift without sleeping does. Employers hardly ever give out these types of contract because they feel that they cannot justify paying employees to sleep whilst they are at work. Another biological rhythm that gets disrupted...
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...Circadian rhythms essay plan. Introduction AO1 Circadian rhythms are biological cycles that last around 24 hours There is a free running cycle controlled by an endogenous pacemaker working as a body clock which is internal to our biological system, such as the suprachiasmatic nucleus which receives information about light and dark directly from the retina of the eye and the pineal gland, which releases melatonin in relation to fading light. Melatonin acts upon the raphe nuclei which in turns produces serotonin, a chemical with an inhibitory or slowing down effect on the central nervous system. Also, circadian rhythms can be controlled by exogenous zeitgebers i.e. external time givers, such as light, temperature and social cues. Another circadian rhythm is body temperature, which is at its lowest at around 4.30 am. The core body temperature also lowers after lunch. Evaluation AO2 Siffre (1962)- He spent two months in an underground cave, without time cues and emerged on the 27th of September, but he thought it was the 20th of August. This suggests that the absence of exogenous zeitgebers, affected his perception of time, therefore giving evidence that endogenous pacemakers control our circadian rhythms. He then carried out further research to see if the absence of exogenous zeitgebers would affect his sleep- wake cycle. He spent six months in a cave, with no time cues, but artificial lights. He settled into a sleep wake cycle of around 25 hours. This therefore gives reliability...
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...Sleep Disorder: Causes and effects to an individual Most of us have already or are experiencing trouble in sleeping every night or every time we’re trying to sleep. This might be normal and usually temporary due to stress, night terrors or some different issues. But if sleep problems are a regular occurrence and interfere with the daily life, we may be suffering from a sleep disorder. Sleep disorders cause more than just sleepiness, there are so many causes. The lack of quality of sleep can have a negative impact on our energy, emotional balance, and health to us. Sleep disorders also are serious enough to interfere with our normal physical, mental and social state. And in worst case, death because of sleepiness and mental condition cause of sleeping disorders. Sleep can affect our overall health. In many cases, people in good health tend to sleep well, whereas those suffering from repeated sleeping problems might have an underlying medical or mental health problem, it may be in minor or serious. Sleeping well is good to physical health and emotional well-being. Unfortunately, even minimal sleep loss can take a toll on mood, energy, efficiency, and ability to handle stress. People with daytime sleepiness are physically fatigue, have a tendency of falling asleep in unsuitable places at unsuitable times, and have poor concentration. Ignoring sleep problems and disorders can lead to poor health, accidents, impaired job performance, and relationship stress. It’s not normal...
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...Circadian Rhythms and Shift Working The concept of circadian rhythms can be a complex matter, however, understanding the basic purpose is quite simple. Associated with all living creatures, from bacteria and insects to plants and animals, circadian rhythms are like metaphorical clocks within an organism's control center (brain) that are responsible for regulating biological functions including wakefulness, sleep, appetite, and temperature. These physiological aspects are absolutely necessary for a healthy life cycle, therefore, ensuring that these cells that control circadian rhythms are properly functioning is crucial to health. Maintaining a balanced lifestyle where we receive an adequate amount of physical activity and sleep as well as nutrients is something that many individuals are aware of, though, when we lead busy lives that disrupt our sleep or appetite patterns, circadian rhythms can become poorly affected and/or altered by negative impacts from daily activities. Shift work, for instance, can often be stressful on our circadian rhythms, which can later lead to avoidable illnesses and diseases. The purpose of this paper is to discuss the basis of circadian rhythms as well as how certain physiological processes can be affected by shift work. Circadian rhythms are regular fluctuations that occur in parts of the body, depending on physiological function; these fluctuations go from high to low points within a twenty-four hour time frame ("Circadian rhythm", n.d.). These...
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...The Clocks Within Us Analysis According to the article published in the February 2015 edition of the Scientific American, genes in the brain, liver, pancreas, and other tissues help keep the various parts of the body in sync. These ideas are portrayed throughout the article written by Keith C. Summa and Fred W. Turek, “The Clocks Within Us.” The article is based around circadian rhythms, which describes how the body works around 24-hour cycles. Both authors are extremely validated when it comes to informing the public on circadian rhythms. Summa is a PhD at the Northwestern University Feinberg School of Medicine and is interested in understanding how to apply research findings to clinical medicine. Turek is a neurobiologist and director of the Center for Sleep and Circadian Biology at Northwestern. He is also the founding president of the Society for Research on Biological Rhythms. Learning more about the different clocks in the body can help explain bodily disruptions caused by out of sync cellular clocks. Circadian rhythms are important in the world of biology because of their effects on one’s health. When all the clocks in our body are not in sync, we can experience diabetes, depression, obesity, and more. The clocks could fall out of sync when sleep and eating patterns falter. This information could have been presented in the Scientific American, a popular magazine that is read by many people across the nation, because many people change their daily patterns. For example...
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...I. Introduction The first time you will hear the word Circadian Rhythm, you will be dreary because you have no idea on what it is about, but because of my drastic intention I will gather more ideas about my topic. Doubtless, I am sure I will make it easier to work with it. One question was bothering me and makes me persevere on doing this Research Paper. “Is it entrainable or not?”, one question with different ideas and information’s sticking with it. No specific and particular reviews I need to provide about it, I just need to gather information by means of researching just to know if Circadian Rhythm is entrainable or not. Although the process is not easy, as people who have suffered from a jetlag, because the more time you did not sleep, the more you will suffer Circadian Rhythm. Sleep and waking, for instance, occur naturally to the beat of an internal pacemaker, which works on a cycle of about twenty-four-hours. My purpose on making and researching is to have broad ideas and I need to answer the question bothering me if it is entrainale or not. I need to defend my title against myself to be proudly to present it and defend it easily.In my title, I used the questioning type because I want to know if Circadian Rhythm is truly entrainable or not. Y abstract focuses on the summary of my entire research paper and what are my goals and objectives on making this research. In listing the methods and procedures, my goal is to give the reader sufficient...
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...fundamental in human circadian rhythms and their disruption can have consequences for behaviour and performance. Such disturbances occur due to domestic or occupational schedules that do not permit normal sleep quotas, rapid travel across multiple meridians and extreme athletic and recreational endeavours where sleep is restricted or totally deprived. There are methodological issues in quantifying the physiological and performance consequences of alterations in the sleep–wake cycle if the effects on circadian rhythms are to be separated from the fatigue process. Individual requirements for sleep show large variations but chronic reduction in sleep can lead to immuno-suppression. There are still unanswered questions about the sleep needs of athletes, the role of ‘power naps’ and the potential for exercise in improving the quality of sleep. © 2006 Elsevier Inc. All rights reserved. Keywords: Circadian rhythm; Exercise; Jet-lag; Shift-work 1. Introduction The sleep–wakefulness cycle is the most discernable of human circadian functions, activity being associated with the hours of daylight and sleep with the hours of darkness. This recurrence on a daily basis is linked with responses of the pineal gland to the environment, its secretion of melatonin being promoted at dusk and inhibited on exposure to morning light. There is a myriad of other biological functions that are knit into a common system of circadian rhythms, cycles in behaviour and in biological functions that recur with a...
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...Bipolar Disorder University of Phoenix Psy 103 September 7, 2009 Bipolar Disorder How would a person know if they had bipolar disorder? Would they just assume that their extreme feelings were normal? Most people would indeed assume that their extreme happiness was normal. However, those people might begin to suspect a problem after they have lain in bed for days not wanting to do anything. These extreme feelings define bipolar disorder. The person is extremely happy or sad with no middle area. Even doctors have a difficult time diagnosing this disorder. The doctor must consider hereditary factors, biological influences, states of consciousness, and the person’s personality. All these factors play a part in the diagnoses and treatment of bipolar disorder. General Behavior Diagnosing bipolar people is difficult because of their general behavior. Bipolar people do show outward signs that a problem exist. However, most people have no idea what bipolar is, let alone the symptoms. Especially since the bipolar disorder has four stages or episodes. Each stage of this disorder can be dangerous. The manic part of the disorder has the person feeling good. They might do risky activities because they think they are invincible. The manic stage can make the person irritable or angry. During the depression episode they will feel very sad for a long period. They do not want to eat, get out of bed, or their normal activities. The depression stage can last for months, making this the...
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...emergency services. As pre-hospital providers they are constantly faced with heavy workloads that are not only physically, but also mentally and emotionally taxing. Fatigue, digestive problems and family conflicts are some factors that may compromise the worker’s aptitude and possibly jeopardize patient safety and the paramedics’ health and overall well-being. The body has its own "biological" clock the helps maintain complex internal functions throughout a 24-hr day. This daily rhythm is known as the circadian rhythm. It is influenced by factors such as light, dark, social contacts, and noise. The human body is meant to be active during daytime hours, and is meant to recover and reenergize during the nighttime hours. Working at night and sleeping during the day is opposite to the body's "biological" clock and what the body naturally wants to do. This may make sleeping difficult, and hamper the body’s ability to recover from the physical and mental demands of a paramedic’s job. Circadian rhythms have been found to be associated with changes in mental and physical performance. Circadian rhythms may partly explain why job performance can vary over a 24-hour period, with a low point occurring very late at night or very early in the morning. Common signs of fatigue include loss of concentration, memory impairment lack of motivation, and longer reaction time resulting in an increased risk of accidents. According to Dement a leading authority in sleep, sleep debt is an accumulation...
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...Most all psychological functioning can be reduced to underlying brain processes. This should serve as reason alone as to why biology plays an important part in the study of psychology. Psychological factors play a role in whether a person develops a mental illness and in how well they recover from a mental illness, yet biological and genetic risk factors, or predispositions, are fundamentals to understanding mental illnesses. In this paper, we will look at Parkinson’s disease as an example of how biology has brought us to a deeper understanding of the psychology of mental illness. Psychology is an academic and applied discipline that involves the scientific study of mental functions and behaviors. Psychologists attempt to understand the role of mental functions in individual and social behavior, while also exploring the psychological and neurobiological processes that underlie certain functions and behaviors. For this reason, biology plays a very important role in the study of psychology. Psychology determines what people perceive to feel and behave, but underlying it all, ultimately determining the way we act, feel and behave, is biology. A biological perspective is relevant to psychology in the study of how the nervous system and hormones work, how the brain functions and how changes in structure and/or function can affect behavior (McLeod, 2007). One example of a psychological field which incorporates biology is Psychobiology. Psychobiology, also known...
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