Biological Rhythem Flashcards
Biological rhythms
Have an important influence on the way in which the body behaves
Controlled by endogenous pacemakers = internal body clock
And influences by exogenous zeitgebrs = external changes in the environment
Ultraduan rhythm
Cycle is less than 24 hours e.g stages of sleep which last approximately 90 minutes
Circadian rhythms
Lasts for 24 hours e.g body temperature and the sleep wake cycle
Infradian rhythms
Lasts longer than 24 hours
E.g female menstrual cycle which operates approximately on a 28 day cycle
Circadian rhythm
Cycle that lasts 24 hours e.g sleep wake cycle
Controlled by endogenous pacemakers internal factors help maintain biological rhythms , have an internal body clock main endogenous pacemaker is called suprachiasmatic nucleas
What are circadian rhythms influenced by ?
Exogenous zeitgebers which are external factors in our environment such as light
Resets the SCN suggests sleep/ wake cycle is not only influenced by endogenous pacemakers
Circadian rhythm- the sleep wake cycle
Controlled by the endogenous pacemaker the superchiasmatic nucleas (SCN)
Eyes notice change in light as less light is recieve by the retina
Sends information to SCN stimulates pineal gland to release melatonin and promote sleep
Circadian rhythms - sleep wake cycle (what happens when eyes detect light again ?
(Exogenous zeitgebers) the SCN is reset which stimulates the SCN and pineal gland
Which inhibits release of melatonin to promote wakefulness
Suggests sleep wake cycle is controlled by endogenous factors
What can biological rhythms also be affected by ?
Exogenous zeitgebers
5 things that happen when the sleep wake cycle is disrupted
Difficulty in sleeping
Decreased attention
Digestive problems
Tiredness and poor reasoning skills
Increased anxiety and irritability
How do we maintain our sleep wake cycle ?
Keep to local times for eating
Kept to local times for sleeping
Stimulate yourself during the day e.g talking (being active)
Use black out curtains to limit artificial light
Not using phones/screens with a backlight late at night
EP and EZ on sleep wake cycle/circadian rhythms Ao3 RTS by Decoursey
RTS effectiveness of EP on sleep wake cycle conducted by Decoursey et al
They destroyed SCN connections in brains of 30 chipmunks who were returned to natural habitats and observed for 80 days
Sleep /wake cycle of chipmunks disappeared and by the end a significant proportion of them had been killed by predators
May be because they were awake and vunreble to attack when they should have been asleep
Support importance of EP such as SCN as EZ along we’re not able to maintain the sleep wake cycle of chipmunks
Increasing validity of research into role of EP and EZ in maintaining sleep
EP and EZ on sleep wake cycle/circadian rhythms Ao3 RTS by Decoursey limitation
Research investigating EP on sleep wake cycle critcused for animal bias
Potentially a problem because humans may have more of a complex interaction between EP and EZ
As there are greater number of zeitgebers than can influence rhythms in humans
Compared to an animals instinctive responses to limited external factors
Thus there are issue with extrapolating findings of research to human
Limited extent to which DeCouseys findings support the importance of EP on sleep wake cycle
RTS EP conducted by Micheal siffre Ao3
Lived in a cave isolated from all EZ for six months
Found within a few days developed a consistent 25 hour cycle and continued to fall asleep on a regular schedule
Suggests sleep wake cycle is controlled by EP due to siffre developing a consistent rhythm when separated from external cues
Increasing validity of research into role of EP and EZ in maintaining sleep wake cycle
