Endogenous pacemakers and exogenous zeitgebers Flashcards
1
Q
What is the suprachiasmatic nucleus (SCM) and where is it located
A
- a bundle of cells located in the hypothalamus in each hemisphere of the brain, it lies just above the optic chiasm and it receives info about light directly from its structure, this continues even when the eyes are closed
- it is one of the primary endogenous pacemakers in the mammalian species and is influential in maintaining circadian rhythms
2
Q
Outline Patricia and DeCoursey et al.’s study
A
- destroyed the SCN in the brains of 30 chipmunks who were then returned to their natural habitat and observed for 80 days
- sleep wake cycle disappeared and by the end of the study many were killed by predators
3
Q
During the night the pineal gland increases the production of what hormone
A
- melatonin, a hormone that induces sleep
4
Q
Outline Campbell and Murphy’s study
A
- 15 ppts were woken at various times and a light was shone on the back of their knees
- researchers managed to produce a deviation in ppts’ usual sleep/wake cycle of up to 3 hours
5
Q
At about how many weeks of age does the circadian rhythm begin
A
- 6 weeks of age
6
Q
At what age are babies entrained
A
- 16 weeks
7
Q
What is a good way of entraining circadian rhythms
A
- following societal standards of eating and sleeping rather than following the babies feelings
8
Q
What is the term used for the idea that there are numerous circadian rhythms in many organs and cells in the body and where are they found
A
- peripheral oscillators
- they are found in the adrenal gland, lungs, liver etc
9
Q
Outline Damiola et al.’s demonstration
A
- changing feeding times in mice could alter the circadian rhythm of cells in the liver by 12 hours whilst leaving the rhythm of the SCN unaffected which suggests there are other factors which can influence the sleep/wake cycle
10
Q
What is a limitation of animal studies (including DeCoursey et al.’s)
A
- ethical issues, animals were exposed to harm
