The Circadian Rhythms Affects Sleep

A rhythm is something that is regularly repeated. All living organisms experience rhythmic changes which tend to coincide with seasonal or daily environmental changes. Most organisms have an internal biological clock called endogenous pacemakers, which are influences by external environmental factors called exogenous zeitgebers, these control periodic changes. The sleep wake cycle is a circadian rhythm that repeats itself every 24 hours. However these can become desynchronised, resulting in a disruption of your biological rhythm. It can be disrupted by many factors, including Jet lag and shift work.

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.

Light helps to regulate circadian rhythms, neuroendocrine responses, and seasonal cycles. (Brawley & Noell, 2008, Pages 2 & 11). Circadian rhythms help derive patterns of sleeping and eating. These circadian rhythms can be triggered by light and are

Through recent findings, I have stumbled upon some really interesting points, which have not only allowed to further my understanding of sleep regulation but have raised some personal discussion points. This point relates to the idea that our circadian clock checks its accuracy everyday using zeitgebers, mainly through light. The exposure to natural daylight stimulates a nerve pathway from special photoreceptive ganglion cells in the retina of the eye, which allows for the calibration of our circadian period. From this information, I reflected on how some of my grandparents, who suffer from vision loss, are able to maintain an appropriate circadian period. I thought that perhaps, through neuroplasticity, an individual could “rewire” its own

In the article “Shedding light on the day-night cycle”, many new researchers found different rhymes encoded to their daily life. Scientists at Washington University School of Medicine discovered different ways to test groups of neurons based on keeping time that will make them be on the same clock. As we know, life on earth is followed by the rising and setting of the sun. Using based knowledge, there are many night owls and morning risers. Stated in the article, “it is important to understand how fundamental timing information is translated into actual neuronal signals in the brain that are controlled by daily rhythms, including rhythmic behavior” (Paul Taghert). Daily cycles are known as circadian clocks. The circadian clock is based on evolution and uses a small amount of proteins which goes up and down by controlling your manner once a day. In the article, scientist do a study based on fruit flies. Liang talks about performing brain scans on live fruit flies every ten minutes for 24 hours. Every fly brain is behaviorally active 150 times in the morning and in the evening. Scientists are improving new tools to help one to identify signals and understand the control timing in the brain in other species.

The circadian rhythm, can be described as a normal attentiveness and or sleepiness experienced through a 24-hour day. The cycle low points, shows a decrease in attentiveness. And the high points state the area where difficult sleep occurs. Shifting the circadian rhythm by one to two hours or backward per day

The circadian rhythm, known as the sleep/wake cycle, is influenced – but not dependent – on the light being received by the suprachiasmatic nuclei. To consider the circadian cycle’s influence

3. Wintering over is a syndrome that 50% of the Antarctic inhabitants experience during the winter. This suggests that:

The Circadian Timing System (CTS) is responsible for generation and synchronization of endogenous oscillations expressed by living beings, for most physiologic functions and behaviors, with period around 24 hours (for review see Dibner et al., 2010). Among the central structures of rodent circadian clock are hypothalamic Suprachiasmatic Nuclei (SCN) and Intergeniculate Leaflet (IGL) in lateral geniculate complex of thalamus. The former is considered the master pacemaker of circadian rhythms, regulating cyclic patterns of physiologic and hormonal activity in response to environmental cues, via a variety of outputs. The latter projects to SCN, via geniculo-hypothalamic tract (GHT), having an important modulatory role in circadian rhythm synchronization

The Circadian system plays the biggest role in the negative feedback loop and acts as an internal clock. It generates a pressure on the body for sleep depending on how long it has been since the last sleep episode. The pressure is greater the longer a person has been awake and there is less pressure the longer a person has been asleep. The pressure is a result of sleep regulating substances that build up in the cerebrospinal fluid while awake. People generally sleep longer if they were awake for a long period of time to compensate for the sleep they had lost. The internal clock can be affected by many external variables such as sunlight, nighttime, when meals are eaten, and the timing of other

The circadian rhythm is a psychological and physical pattern that each human experiences in order to maintain homeostasis. The circadian rhythm can manifest in mental alertness, the sensitivity to pain, various hormone secretions, and most obviously, the sleep-wake cycle. In Latin, circadian rhythm translates to “about” and “day”.

One of the most important roles demonstrated within circadian rhythms is the master clock, located in the suprachiasmatic nuclei (SCN). The suprachiasmatic nuclei consists of many neurons, serving functions that regulate the activity of the circadian clock. These neurons have the ability to express circadian oscillators, which generates the daily rhythms in behaviour and physiology (Antle and Silver 2005). These oscillators undergo phases, and to prevent mutations from occurring within the clock gene, these phases are pulled closer together so that the system remains rhythmic (Antle and Silver 2005), limiting the sleep

The human body has many cycles that occur throughout the day. These cycles are commonly referred to as circadian rhythms. Probably the most well-known circadian rhythm is sleep. What exactly sleep does is not fully understood, although it is surmised that the body repairs itself from the wear and tear of the day and replenishes chemicals that were used up throughout the course of the day. The mind also uses sleep for the purpose of making sense of the events of the day. Even small disruptions in this daily cycle impair the ability of a person to both reason effectively and perform physically.

This study is important because it allows us to better understand the mechanisms that regulate essential biological functions such as pupil control and circadian rhythm. This research is especially relevant to those who suffer from certain disorders that disrupt normal biological responses and functions, such as hypernychthemeral syndrome. Hypernychthemeral syndrome, or Non24, is characterized by delays in tiredness as well as continuous shifts in awareness. Non24 is just one of many circadian

Circadian rhythms are endogenous rhythms that mammals and plants exhibit. The term “circadian” was established in the 1950’s and is derived from the Latin prefix circa- which means “approximately,” and dies- which means “day.” (2) Nearly all living things have circadian rhythms that approximate to a 24 hour cycle; however there are some differences in lengths varying from species to species. (1) Numerous physiological processes are governed by the circadian rhythm, and by effect nearly every process in the body can be contributed to a rhythm of circadian fashion. The master clock of the circadian rhythm for biological processes is the suprachiasmatic nuclei, or SCN. (1)(2) The SCN is located in the anterior portion of the hypothalamus, posterior to and slightly inferior to the frontal lobe of the brain. The SCN is believed