BOO!

Hahas!Yesterday was pretty fun (:

Lol, yesterday after my CCA, WenYee and I went to Mr.Lim there to type again!I typed 3 whole secondary comprehension along with the question and the answer(the question and answer are on separate piece of paper) in 3 and half hours or so.Hahas.Its not that easy okay.Typing really requires concentration and its very energy-cosuming.But I still survived!! ((:

WenYee!Don't worry!You can do it :]]

Oh and Mr.Lim says he will visit my blog one day.Well,let's see when he will come (:

The website of the tuition is still under renovation. ):

*ahem*My dearest WenYee,I AM NORMAL TOO.Stop giving me that look!!Hahas!

Lols then after the typing,we went to eat at the hawker centre near the tuition centre.And gosh,we really have a lot to chat about.We chatted for 1hour ++.I never thought we will hit so well.Hahas we talked mostly about school and CCA(And again I was reminded of how drama clubs in other school are doing.I shall not elaborate).

Hahas.Mr.Lim told us a very interesting thing about sleeping.

CIRCADIAN RHYTHM
A circadian rhythm is a roughly-24-hour cycle in the physiological processes of living beings, including plants, animals, fungi and cyanobacteria. The term "circadian", coined by Franz Halberg,[1] comes from the Latin circa, "around", and diem or dies, "day", meaning literally "about a day." The formal study of biological temporal rhythms such as daily, weekly, seasonal, and annual rhythms, is called chronobiology.

In a strict sense, circadian rhythms are endogenously generated, although they can be modulated by external cues such as sunlight and temperature.

Animal circadian rhythms
Circadian rhythms are important in determining the sleeping and feeding patterns of all animals, including human beings. There are clear patterns of core body temperature, brain wave activity, hormone production, cell regeneration and other biological activities linked to this daily cycle.

There are many health problems associated with a disturbance in the human circadian rhythm, such as Seasonal Affective Disorder (SAD), and delayed sleep phase syndrome (DSPS). Circadian rhythms also play a part in the reticular activating system.

Impact of light-dark cycle
The rhythm is linked to the light-dark cycle. Animals kept in total darkness for extended periods eventually function with a "free-running" rhythm. Each "day," their sleep cycle is pushed back or forward (depending on whether the endogenous period is longer or shorter than 24 hours). The environmental cues that each day reset the rhythms are called Zeitgebers (German, literally "Time Givers"). Interestingly, totally blind subterranean mammals (e.g., blind mole rat Spalax sp.) are able to maintain their endogenous clock in absence of the external stimuli.

Free running organisms still have a consolidated sleep-wake cycle when in an environment shielded from external cues, but the rhythm is not entrained and may become out of phase with other circadian or ultradian rhythms such as temperature and digestion. This research has influenced the design of spacecraft environments, as systems that mimic the light/dark cycle have been found to be highly beneficial to astronauts.

Suprachiasmatic nucleus
The circadian system can be divided into three major components: the central oscillator or pacemaker; the afferent pathways which carry entraining environmental information to the oscillator; and the efferent pathways that communicate the rhythmicity of the oscillator to the physiology and behavior of the organism.

The circadian "clock" in mammals is located in the suprachiasmatic nucleus (SCN), a pair of distinct groups of cells located in the hypothalamus. Destruction of the SCN results in the complete absence of a regular sleep/wake rhythm. The SCN receives information about illumination through the eyes. The retina of the eyes contains not only "classical" photoreceptors but also photoresponsive retinal ganglion cells. These cells, which contain a photo pigment called melanopsin, follow a pathway called the retinohypothalamic tract, leading to the SCN. If cells from the SCN are removed and cultured, they maintain their own rhythm in the absence of external cues.

It appears that the SCN takes the information on day length from the retina, interprets it, and passes it on to the pineal gland (a pea-like structure found on the epithalamus), which then secretes the hormone melatonin in response. Secretion of melatonin peaks at night and ebbs during the day.

Outside the SCN "master clock"
Recently, evidence has emerged that circadian rhythms are found in many cells in the body outside the SCN "master clock." Furthermore, liver cells, for example, appear to respond to feeding rather than to light. Cells from many parts of the body appear to have "free-running" rhythms.

Cells in the body that have their own rhythms are called peripheral oscillators. These tissues include the esophagus, lung, liver, spleen and thymus. There is some evidence the olfactory bulb and prostate may also experience oscillations when cultured, suggesting these structures may also be weak oscillators.

Disruption
Disruption to rhythms usually has a negative effect in the short term. Many travelers have experienced the condition known as jet lag, with its associated symptoms of fatigue, disorientation and insomnia. A number of other disorders, for example bipolar disorder and some sleep disorders are associated with irregular or pathological functioning of circadian rhythms. Recent research suggests that circadian rhythm disturbances found in bipolar disorder are positively influenced by lithium's effect on clock genes.

Disruption to rhythms in the longer term is believed to have significant adverse health consequences on peripheral organs outside the brain, particularly in the development or exacerbation of cardiovascular disease. Timing of treatment in coordination with the body clock may significantly increase efficacy, and reduce drug toxicity, or adverse reactions. For example, timing treatment of angiotensin converting enzyme inhibitors (ACEi) may reduce nocturnal blood pressure, also benefit left ventricular (reverse) remodeling.

Relationship to cocaine
In addition, circadian rhythms and clock genes expressed in brain regions outside the SCN may significantly influence the effects produced by drugs such as cocaine.

Moreover, genetic manipulations of clock genes profoundly affect cocaine's actions.

Source:wikipedia.com

Are you sleepy sometimes in the afternoon? Do you seem to handle physical tasks more easily late in the day? If so, you already know about circadian rhythms.

Your body has more than 100 circadian rhythms. Each unique 24-hour cycle influences an aspect of your body's function, including body temperature, hormone levels, heart rate, blood pressure-- even pain threshold. Understanding how these cycles interplay is fascinating. And, in some cases, you may be able to plan your day to take advantage of your body's natural rhythms.

How your body keeps time
In your brain is a type of "pacemaker" called the suprachiasmatic (soo-prah-ki-az-MAT-ik) nuclei. This area of your brain regulates the firing of nerve cells that seem to set your circadian rhythms.

Scientists can't explain precisely how this area in your brain "keeps time." They do know your brain relies on outside influences, "zeitgebers" (ZITE-ga-berz), to keep it on a 24-hour schedule.
The most obvious zeitgeber is daylight. When daylight hits your eyes, cells in the retinas signal your brain. Other zeitgebers are sleep, social contact and even regular meal times. They all send "timekeeping" clues to your brain, helping keep your circadian rhythms running according to schedule.

Rhythms control your day

Almost no area of your body is unaffected by circadian rhythms.

Sleep and wake--It may seem you sleep when you're tired and wake when you're rested. But your sleep patterns follow a circadian rhythm.

You're most likely to sleep soundly when your temperature is lowest, in the wee hours of the morning. You're also most likely to awaken when your temperature starts to rise around 6 to 8 a.m.

As you age, your brain's "pacemaker" loses cells. This changes your circadian rhythms, especially noticeable in how you sleep. You may nap more, have disrupted sleep and awaken earlier.

Temperature--Your temperature is lowest when you're inactive. And activity can make your temperature rise. But despite these factors, your temperature also follows a definite circadian rhythm.

In the late afternoon, your temperature can be as much as 2 degrees Fahrenheit higher than in the morning. And it will rise and fall even if you never see daylight.

Hormone production--Almost all hormones are regulated, to some extent, by circadian rhythms.
Cortisol affects many body functions, including metabolism and regulation of your immune system. Its levels are highest between 6 and 8 a.m. and gradually decline throughout the day. If you change your daily sleeping schedule, the peak of cortisol's cycle changes accordingly.

Growth hormones stimulate growth in children and help maintain muscle and connective tissue in adults. Sleep triggers hormone production, regardless of when you go to bed. Production peaks during the first two hours of sleep. If you're sleep deprived, production drops.

Cardiovascular system--More strokes and heart attacks occur in the morning than at any other time of day. This makes some people wonder if morning exercise is safe.

But experts contend morning changes in your body--not exercise-- may be responsible for cardiovascular problems. Blood clots most rapidly at about 8 a.m.

Blood pressure also rises in the morning and stays elevated until late afternoon. Then it drops off and hits its lowest point during the night.

These changes occur independently of physical activity. Exercise at any time of the day is beneficial.

On the other hand, if you're training for athletic competition, you may have reason to schedule that event later in the day. Athletes seem to perform best in the late afternoon, when strength, body temperature and flexibility peak.

Pain tolerance--Athletes who compete late in the day may perform better because they can "gain" without as much "pain." Pain tolerance is highest in the afternoon. One study shows tooth pain is lowest in the late afternoon, a consideration when you schedule your next dental appointment.

Medication--Scientists are looking at how circadian rhythms affect the way your body uses medications. One finding is that less anesthesia is needed to cause analgesia or drowsiness when administered in the afternoon.

Experiments with cancer medications are trying to find the time of day when the drugs are the most helpful with the fewest side effects.

Stay on schedule
Changes in daily habits such as a short night's sleep can disrupt your circadian rhythms. You may be able to stay "in sync" by keeping a consistent daily schedule

Source: http://www.hallym.ac.kr/~neuro/kns/tutor/medical/rhy.html

LOL.So I have come to the conclusion that I shall sleep early tonight (:

HAHAS.Nurmatha!Don't think so much too!And wait,who says you can grab my photo!Lols.Thanks anyways for the post ^^

Squirtle has swum to the other side of Singapore to have his chalet.Hahas.Have fun!

Talking about chalets,THERE IS NO 2e6 AND 6/1 CHALET!