Endogenous Pacemakers And Exogenous Zeitgebers Flashcards
What are Endogenous Pacemakers?
Internal body clocks that regulate biological rhythms
What are Exogenous Zeitgebers?
External changes in the environment that affect biological rhythms
What is the Suprachiasmatic Nucleus (SCN)?
A bundle of nerve cells in the hypothalamus in each hemisphere
What does the Suprachiasmatic Nucleus (SCN) do?
Maintains the sleep/wake cycle by receiving information about light (even if eyes are shut) and adjusts it accordingly
What type of animal and how many did DeCoursey et al use in their study of the SCN?
30 Chipmunks
What did DeCoursey et al do to the chipmunks in their study?
Destroyed their SCN connections
What happened to the chipmunks in DeCoursey et al.’s study after they had been placed back in their natural habitat?
Their sleep/wake cycles had disappeared and most of them were killed by predators
How do the SCN and the pineal gland work together?
The SCN passes information about light and day length to the pineal gland in order for it to produce the right amount of melatonin
What is an ethical limitation of DeCoursey et Al’s study?
Chipmunks were non-consensually exposed to considerable harm and some even died
What is a limitation of DeCoursey et Al’s study?
Lacks generalisability - humans and chipmunks have very different day-to-day lives - chipmunks don’t have to get up for work/use alarms etc.
What did Campbell and Murphy prove about light as an exogenous zeitgeber?
That lights does not need to be detected by the eyes in order to reset/change the sleep/wake cycle
How did Campbell and Murphy investigate light as an exogenous zeitgeber?
They shone light onto the back of 15 participants knees
What is an example of social cues as an exogenous zeitgeber?
Mealtimes and bedtimes imposed by parents
