Biological Rhythms & Sleep

[Brendon Fulton]

Very briefly define the following:

• Circadian Rhtyhms
  
• Infradian Rhtyhms
  
• Ultradian Rhtyhms
  

[Brendon Fulton]

Discuss one or more of the following:

• What function is served by sleep?
  
• What happens when we are deprived of sleep?
  
• Why do all animals sleep?
  

[George jupp rowlands]

Circadian Rhythms-This Rhythm is a biological process which goes over 24/25 hours. this is effected by the suprachiasmatic nucleus which feeds of external factors such as darkness.

Infradian Rhythms- This is a biological process as well and is over the course of a single day a good example of this rhythm is a ladies menstrual cycle as it happens over the course of twenty eight days.

Ultradian Rhythms- This is the third rhythm and is also a biological process this is a rhythm that has a duration of less than 24hrs. This is used in sleep ad is in reference to the 90-120 minutes cycling of the sleep stages during human sleep.Other types of cycles can be hormonal in this rhythm.

What function is served by sleep?
One fuction of sleep is to rest and to revitalize our energy store in doing this the body temperature increases hence why humans sweat at night drastically and thew heart rate decreases and melatonin is increased in order to make us more tied and sleepy with all of this the metabolism slows down as well. the functions of sleep are based around the SNC and the biological clock inside of us as humans and the circadian rhythm which is 25 hrs and goes off the Earths rotation on it's axis. The SNC is sensitive to light and as said sends a message to the pineal gland which release melatonin.

[danieljacobs]

Circadian Rhythm:
A circadian rhythm is a roughly 24-hour cycle in the biochemical, physiological, or behavioral processes of living organisms.

Infradian Rhythm:
Is a longer cycle than the circadian rhythm such as breeding, menstruation, tidal or seasonal rhythms.

Ultradian Rhtyhms:
the regular recurrence in cycles of less than 24 hours, as certain biological activities which occur at such intervals, regardless of conditions of illumination.

What function is served by sleep?
I feel that sleep is used to reserve energy, and to more-less file any loose data that is learnt through out the day into the brain, many other convincing theories consist of the bodies need to hibernate in a considerate drop in temperature or that the body recovers quicker when in an unconscious state.

What happens when we are deprived of sleep?
Many say that people become grouchy or moody when not had enough sleep, though this has been proved wrong by a study that says most of the worlds successful business people sleep for up-to 5 hours, 3 hours below the national average. also disorders such as insomnia and hyper insomnia can be developed through the laq of sleep, many people die from insomnia.

[dthorn]

- A Circadian Rhythm is an external biological process affected by different zeitgeists such as light/darkness which lasts more that 24 hours.

- An Infradian Rhythm has a duration of one day, a perfect example would be the menstrual cycle which occurs every 28 days.

- Lastly the Ultradian Rhythm which is a rhythm that happens in less that 24 hours.

What Function is Served by Sleep?
- No-one really knows what funcion of sleep is, many assume that it's to replenish energy, but horses only sleep for approx 2 hours a night and can still run around during the day.
At night our heart rate is decreased where our melatonine levels increase in order to make us tired and sleepy.
Others think that we sleep in order for our brain to file our memories of that day.

What happens when we are deprived of sleep?
- The stereotypical thing people think of when talking about sleep deprivation are bad moods and lack of concentration.
The fact is that studies have proven that the most successful and most healthy people are those who are getting 4-5 hours sleep instead of the usual 8 or 9 hours.
The most severe thing to happen from sleep deprivation is death, this severity of chronic insomnia is very rare but usually occurs at about 20 years.

[amara002]

Circadian rhythms: The circadian rhythm is a cycle that consists of roughly 24 hours. It applies to many different organisms including plants, animals, fungi and even cyanobacteria.

Infradian Rhythms: The infradian rhythm is a biorhythm and lasts for longer than one day, a good example of this is a women's menstrual cycle.

Ultradian Rhythm: The ultradian rhythm cycles or repeats in less than a day. A psychological example of this is the change in hemispheric dominance (from left to right) during sleep and waking hours this occurs about every 90 minutes.

What happens when we are deprived of sleep ?
Sleep deprivation has many negative effects on people such as decreased daytime alertness, impaired memory and cognitive ability. If sleep deprivation is continued or there is a disorder such as insomnia or hyper insomnia it can lead to an impaired immune system and even death. This is contradicted by the fact that some people only need around 4-5 hours of sleep and are able to function optimally, this is significantly lower than the general trend of needing 8 hours.

[Brendon Fulton]

Some good responses here from those of you that have contributed.

Remember that the Infradian Rhythm is a biological rythym that exceeds the 24/25 hour cycle...

[Mr Bausor]

An important concept to note is zeitgeber. This is an external cue that moderates our sleep/wake cycle. i.e. the cycle light and dark 'resets' our body clock and adjusts our sleep wake patterns. This is one of the ways that these cycles are controlled by the body.[/color]

[ryan]

Circadian Rhythm:
A circadian rhythm is a roughly 24-hour cycle in the biochemical, physiological, or behavioral processes of living organisms.

Infradian Rhythm:
Is a longer cycle than the circadian rhythm such as breeding, menstruation, tidal or seasonal rhythms.

Ultradian Rhtyhms:
the regular recurrence in cycles of less than 24 hours, as certain biological activities which occur at such intervals, regardless of conditions of illumination.

[Brendon Fulton]

Mr Bausor talks about light and dark resetting our body clocks and affecting our sleep/wake cycles.

Discuss the process that causes this...