961523
Description
Mind Map by 07setchfields, updated more than 1 year ago
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Created by 07setchfields
almost 11 years ago
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Endogenous pacemakers and Exogenous zeitgebers
- Endogenous pacemakers
- Suprachiasmatic nucleus
- Lies in the hypothalamus, it is located just above the place were
the two optic nerves from each eye cross, this allows it to obtain
information about light from the eyes.
- The SCN sets an approximate 24 hour cycle through interactions of
pairs of proteins which create the "tick" of the biological clock
- The SCN sends signals to the pineal gland to regulate the production
and secretion of melatonin.
- When it gets dark the SCN signals to the pineal gland to
increase production. which induces sleep.
- When it gets dark the SCN signals to the pineal gland to
increase production. which induces sleep.
- Lies in the hypothalamus, it is located just above the place were
the two optic nerves from each eye cross, this allows it to obtain
information about light from the eyes.
- Commentary
- Support
- Case study individuals such as michel Stiffre who lived in a cave fro 61 days with no
external cues show that even without these the body will resume a cycle of 24 hours.
- However a problem with case studies is that the data from one
individual cannot be generalised to the rest of the population
- However a problem with case studies is that the data from one
individual cannot be generalised to the rest of the population
- Chipmunk study
- If the SCN is removed we would expect
the circadian rhythm to be disrupted
- Decoursey found that when he removed the SCN of chipmunks and
returned them to the natural habitat, all of them had died after 80
days as they werent sleeping at the adapted time to stay safe
- If the SCN is removed we would expect
the circadian rhythm to be disrupted
- Case study individuals such as michel Stiffre who lived in a cave fro 61 days with no
external cues show that even without these the body will resume a cycle of 24 hours.
- Problems
- Animal study evaluation
- However with animal studies we need to be careful
with generalisation of the findings onto humans.
- It is likely that humans will be more
influenced by external cues that animals
- Also research has shown that the biological rhythms are not the same
across all species so research would have to be checked against humans.
- However with animal studies we need to be careful
with generalisation of the findings onto humans.
- Animal study evaluation
- Support
- Suprachiasmatic nucleus
- Exogenous zeitgebers
- The endogenous pacemaker can be reset or delayed by
these exogenous zeitgebers.
- Light is the most influential cue, however others such as social cues
and temperature can also have an effect on the rhythm
- research by Campbell and Murray has found that the rhythm can be shifted
just by shining a light on the back of the knee, this shows the power of light
as a exogenous zeitgeber.
- The endogenous pacemaker can be reset or delayed by
these exogenous zeitgebers.
- Relationship between exogenous zeitgebers and
endogenous pacemakers
- Our circadian rhythm is controlled by the
internal clock- endogenous pacemaker.
- However sometimes different external factors can play influence
into when we sleep, such as seasonal changes and social cues.
- These are called Exogenous xeitgebers
- These are called Exogenous xeitgebers
- Our circadian rhythm is controlled by the
internal clock- endogenous pacemaker.
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