Biological rhythms

Biological rhythms

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  • Created by: Shaheen
  • Created on: 20-03-11 18:32

Psychology Revision Biological Rhythms, Sleep and Dreaming…

Biological Rhythms-A rhythm is something that is regularly repeated e.g. eating several times a day. These rhythms are repeated over different intervals and they are governed by both internal (endogenous) and external (exogenous) factors..

  • Endogenous Pacemaker = something internal that sets the rhythm..
  • Exogenous zeitgeber = something external that affects / sets the rhythm e.g. light...                              

Circadian Rhythms -A circadian rhythm is 24-hour cycle that the body has for example  temperature, heart rate and the sleep wake cycle...

 

Explanation-The Suprachiasmatic Nucleus (SCN) is a small group of cells in the hypothalamus; it lies just above the optic chasm so it can gain input fairly directly from the eyes...

 

Study-Morgan removed the SCNs from hamsters and found that their circadian rhythms disappeared. He also transplanted that SCNs from hamsters who had mutant circadian rhythms to ‘normal’ hamsters. He found that the hamster receiving the transplant took on the mutant circadian rhythms...

Silver et al also found that if SCNs are transplanted into an animal who’s SCN has been removed; the animal receiving the transplant have a restored circadian rhythm...

Ultradian Rhythms-This is a rhythm that last less than 24 hours, an example is the sleep cycle. We all sleep in a cycle of 5 stages...

Infradian Rhythms-An infradian rhythm lasts for more than a day for example the menstrual cycle which occurs once a month...

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Ele.

Please can you edit this so all the text can be seen.

Thanks,

Ele (moderator)

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