E.P's and E.Z's Flashcards
What is an endogenous pacemaker?
An INTERNAL body clock that REGULATES our BIOLOGICAL rhythms
What are 2 examples of endogenous pacemakers?
Suprachiasmatic nucleus.
Pineal gland
What does the suprachiasmatic nucleus do?
It’s the MAIN ep in mammals. Controls bio rhythms, recieiving information on LIGHT via the optic nerve, ADJUSTING body clock so that it’s in step with outside world.
what does the pineal gland do?
SCN sends signals to the pineal gland. The light sensed produces melatonin in the pineal gland which is inhibitted.
LIght = low melatonin so we WAKE.
No light= melatonin is produced so we fall asleep.
SIFFRE’s reseasrch on endogenous pacemakers.
(cave guys)
Circadian rhythms show IMPORTANCE of ep’s because findings show that free-running ep’s wihtout influence of e.z’s are NOT successfully ENTRAINED to a 24 hour cycle, but EP’s still produce a cycle.
We need EP’s for the sleep wake cycle to be 24 hours.
MARTIN RALPH
Bred a strain of MUTANT hamsters with ABNORMAL circadian rhythms of 20 hours.
SCN nuerons from mutant hamsters implanted into NORMAL hamsters who TOOK on the 20 hour rhythm
Indicating that the SCN which is an EP plays an ESSENTIAL role in establishing and regulating the circaidan rhythums .
What are exogenous zeitgebers?
an EXTERNAL factor that ENTRAINS our biological rhythm. Without this cue, our E.P’s are FREE-RUNNING.
What are 2 examples of ez’s?
LIGHT and SOCIAL CUES
What does light do?
Synchornises our clock with the outside world (ENTRAINMENT)
research into E.Z’s Campbell and Murphy
demonstrated how LIGHT can ENTRAIN out biological rhythms through SKIN receptor cells
15 ppts woken at various times, light shone on back of KNEES, some experiences DEVIAITON in sleep for up to 3HRS.
Suggests that light is a powerful exogenous zeitgeber, even when it doesn’t reach our EYES.
