endogenous pacemakers

• endogenous pacemakers

  biological rhythms in the body are affected by endogenous pacemakers. these are internal mechanisms that influence biological rhythms such as the sleep/wake cycle. they are our internal body clocks that can also be affected by external environment such as light

  suprachiasmatic nucleus is the most important endogenous pace maker. light sensitive receptors in our eyes inform suprachiasmatic nucleus to enforce pineal gland to release melatonin or not. bright light won't release melatonin giving a feeling of wakefulness, whereas dim/no light releases melatonin making us tired
• A03 - SUPPORTIVE STUDY

  MORGAN bred hamsters with a circadian rhythm of 20 hours instead of 24, and then transplanted them into normal hamsters. he found the hamsters ended up developing a 20 hour circadian rhythms. this therefore establishes clear cause and effect relationships between scn and its affect on biological rhythms in the body

  HOWEVER, findings cannot be generalised to humans as animals have differences in cognitive functions and processing. similarly, due to ethical issues study cannot be replicated on humans
• A03

  -exo and endo have been agued to be limited as they are studied as separate processes. evidence has shown that these two processes are parallel to each other and should be studies holistically. e.g exo factors such as light affect the scn and its release of melatonin meaning these two factors work interdependently to control the sleep/wake cycle. thus, they should be studies together which increases the mundane realism and ecological validity of these two factors as it represents the real life scenarios of how they work , aswell as being more comprehensive
• A03 -hard biological determinism - states that exo and endo factors are the only reason we sleep/wake. but this fails to mention social factors that influence jet lag/ when we sleep such as caffeine, quality of sleep from the night before and being around large crowds. this only adopts a biological explanation to explain the sleep/wake cycle, when there are many different factors that affect it. a soft deterministic approach is more acceptable as we have control over when we want to sleep/ wake however we eventually give in to our endogenous pacemakers.