Circadian Biological Rhythms

You may choose to respond to this assignment yourself or interview another person. We often hear people commenting that their “biological” or “social clock” is ticking. What are the settings on your social clock? At what age do (did) you expect to be married? Have children? If you do (did) not marry by this time, what would you do? If you were told that you could not have children, what would you do? How would the absence of a spouse and/or children impact your plans for the future?

To explain the control of biological rhythms by just referring to endogenous pacemakers such as the SCN is an example of biological reductionism. This is a limited approach as it is partial and does not take account of the interaction of endogenous pacemakers with exogenous zeitgeber. The psychologists assume that the damage to the SCN is the only causation of the disturbed sleep there is no consideration that the sleep-waking cycle could be a more complex mechanism. The SCN is connected to the pineal gland which could be the underlying cause of the disturbed sleep, due to the damage of the SCN this connection may mean that melatonin is no longer secreted efficiently. This would suggest that the SCN is only a factor within a larger pathway. Michel Siffre however did take into account the interaction of endogenous pacemakers and exogenous zeitgebers.

Humans have a natural rhythm of 25 hours of sleep and wakefulness, in order to reset this the brain plays an important role with the suprachiasmatic nucleus which is a cluster of neurons in the medial hypothalamus of the brain. The SCN

McMahon , et al, 2014). Another factor that can play into S.A.D. is melatonin, which helps with sleep and wake cycles. Rosenthal, et al, notes how the pineal gland, the gland that produces melatonin, will react to dark surroundings with drowsiness that can lead people to being lethargic (as cited in Melrose, 2015). When melatonin increases and serotonin decreases, the offset of the proteins can cause circadian rhythms to be disrupted, which is the bodies “24 hour” clock. Researcher Melrose writes that “…circadian rhythms respond to the rhythmic light-dark changes that occur daily and throughout each of the seasons.” (2015). People with S.A.D. disorder normally find that their circadian rhythms are off beat and timed differently with day lengths, for example feeling tired in the middle of the day while being wide awake or feeling wide awake when it would normally be time to sleep.

B. Biological clocks are an instinctive and internal timing mechanism that is made from special molecules.

Circadian dysrhythmia, also known as jet lag, is a disruption in the body’s cycle due to traveling (Prentice, 2015). When traveling one or more time zones, the human body can be affected in many different ways. For example, jet lag can cause people to be more fatigued during the day, have decreased motivation, a loss of appetite, a feeling of disorientation, impaired physical and mental performance, a lack of concentration, and an altered sleep schedule (Kolling, Ferrauti, Pfeifer, Meyer, and Kelllmann, 2016). These can be game changing problems in athletics because teams are constantly traveling back and forth. Athletic trainers can work with athletes to treat and prevent these circadian dysrhythmia signs and symptoms.

The SCN is two different clumps of nerve in your upper brain. The SCN uses different clues to register daylight, and stay awake and sends a signal to your body to stay awake.At night the SCN stops sending the signal to your brain and produces a chemical that makes you tired. After you fall asleep the

In vertebrates, melatonin is synthesised in the pineal gland (Foulkes et al. 1997). In mammals however, the pineal cells found within the gland are not light reactive nor do they have a circadian clock imbedded inside (Foulkes et al.

Organisms, whether they happen to be nocturnal or diurnal always have a sort of involuntary or in the words or Ivan Pavlov, ‘unconditioned reflex responses’ that they use to determine when to sleep and wake. Biologists universally believe that organisms have a type of biological clock controlling their various cycles for daily activities. According to the American Heritage’s Dictionary of Student Science, 2014, the daily biological activities are referred to as circadian rhythms and are influenced by light and dark 24-hour day regular intervals. The rhythms are controlled by hormones and regulated by the brain, but can be disrupted by the alteration of daily schedules like exposure to light during night time hours. (American Heritage, 2014). Different organisms have different ways of handling their sleep-wake cycles as we will see in the analysis of cycles that are characteristic of the giraffe, the camel, and the desert snail. This paper will analyze sleep patterns of each organism, how different their sleep cycle is from that of the human cycle, whether they are nocturnal or diurnal, and whether any of them dreams.

Researchers used luciferase on fireflies to study this mechanism. The result showed some significant results about how this “clock gene” affect behaviors. With enough enzyme, researchers can repress the DNA at the clock gene and completely change the behavior of any animal. The gene also provided some explanations for how light exposure can change human’s behaviors. From the talk, Dr. Herzog mentioned that the VIP (vasoactive intestinal polypeptide) cells in the suprachiasmatic nucleus can respond to light. Therefore, when the light shifts our daily behavior, it means that the VIP cells must be activated somehow in the SCN. The activation of VIP results in a chain of reactions inside the suprachiasmatic nucleus and cause a shift in circadian

Chronotype (CT) is part of the circadian routine and it is defined as an individual’s inclination in rise and sleep timing (Horne & Ostberg, 1977). Chronotypes comprise three different groups; morning, intermediate, and evening group (Adal et al, 2012). Specifically, the early group rise and sleep early, while individuals who belong to the evening group rise and sleep later than the morning group, whereas the intermediate group does not follow a specific pattern (Adal et al, 2012). Interestingly, around 40% of the individuals belong to one of the two poles, morning or evening group (Adal et al,

Circadian rhythm is our very own biological clock that has regular bodily rhythms that occur on a 24-hour cycle. This “clock” is what controls our sleep cycle, along with body temperature and wakefulness. The bodily clock does a good job, but sleep isn’t perfect. There are many sleep disorders that can turn out peaceful night of sleep into a nightmare, and not like a dream kind of nightmare. The most prevalent one of these is insomnia, or the persistent problems in falling or staying asleep, with 1 in 10 adults having some sort of the disorder. There is also narcolepsy, or sudden attacks of overwhelming sleepiness, sleep apnea, or the sudden lack of breathing during sleeping, causing the victims to awaken, and night terrors, or a sleep disorder characterized by high arousal and an appearance of being terrified (Myers,

This paper is concerned about circadian rhythms and metabolic health, which can be affected by the timing of food intake. Also, the paper is concerned about the affect it has on mice when consuming a large meal before breakfast, and smaller meal for dinner compared to mice who only consumed breakfast. This paper suggests that during inactive period, the consumption of high-fat foods results in weight gain. What they are now concerned about is the timing, and size of the meal being consumed to show if this has an effect on mice.

Origin of melatonin is estimated 2.5 billion years and perform the function of an antioxidant to detoxify the free radicals generated during the process of aerobic metabolism with the other functions of melatonin presumably being acquired during evolution (Tan et al. 2010, Tan et al. 2013). Melatonin is an important hormone which regulates the physiology (energy metabolism, reproduction, anticancer etc.) of an organism through environmental stimuli, including the biological clock in animals. The daily secretion pattern of melatonin is highly conserved among vertebrates; it is high during the night and low during the daytime. In this way, melatonin acts as the internal neurohormonal signal of darkness and plays a role as a “zeitgeber” (Falcon

Aside from noticing night and day and clocks our body has its own system to tell us when to sleep and when to wake, our circadian rhythm. The human body naturally runs on a twenty five hour clock, so living on a twenty four hour schedule is often hard on the body because it loses an hour each day. On top of this natural loss most people do not get the right amount of sleep each night which can cause a whole host of problems. This is part of