Endogenous Pacemakers + Exogenous Zeigtbers Flashcards
Endogenous pacemakers
Internal body clocks that regulate our bio rhythms such as influence of SCN on sw cycle
Suprachiasmatic nucleus
SCN = tiny bundle of nerve cells located in hyp of both hemipheres
Influential on circadian rhythm - sw cycle
SCN lies above optic chiasm and receives info about light directly from this structure
Continues when eyes r closed, enabling bio clock to adjust changing patterns of daylights which we r asleep
Animal study
De coursy et al
Sw dissapered when destroyed scn connections in brain of 30 chipmunks
Observed for 80 days and lots of them were killed by predators as were awake and vulnerable but should have been asleep
Pineal gland + melatonin
Pea like structure behind hyp
During night, pg increases melatonin production - chemical that induces sleep + is inhibited during periods of wakefulness
Has some influence in sad
Exogenous zeitgebers
Eternal cues that may affect or entrain our bio rhythms such as influence of light on sw cycle
In absence of external cues - free running bio clock that controls sw cycle continues to tick in cyclical pattern (siffre)
Social cues
Iight
Light
Key zeitgeber in humans
Can reset bodies main endo p (scn)
Has indirect influence e on jet processes such as hormone secretion and blood circulation
Campbell + Murphy found light may be detected by skin receptors sites on body even when same info is not received by eyes
Light shone on back of knees of p’s and found deviation in their sw cyckes’s
Social cues
Babies - sw cycle is random
Circadian rhythm begins at about 16 weeks
Most babies r entrained.
Schedules imposed by parents r key influence such as adult determined meal times and bedtimes
Jet lag - research suggests adapting to local times for eating and sleeping rather than responding to own feeling is an effective way to roof entrains circ r and beating jet lag
