Biological Rhythms Flashcards
What is a biological rhythm?
A series of repetitive biological processes regulated by your internal clock.
What are biological rhythms regulated by?
-Endogenous pacemakers.
-Exogenous zeitgebers.
What is the main example of an endogenous pacemaker?
-SCN.
What are examples of an exogenous zeitgeber?
-Light.
-Social cues (e.g. meal times).
What are endogenous pacemakers?
The body’s internal body clocks that regulate biological rhythms.
What are exogenous zeitgebers?
External environmental cues that reset our biological clocks.
Can endogenous pacemakers be affected by the environment?
Yes.
What do external cues do to biological rhythms?
External cues entrain biological rhythms.
What is a free running cycle?
Where one’s daily sleep cycle does not depend on external cues.
Where is the SCN?
The hypothalamus.
What is the SCN linked with?
The pineal gland.
How does the sleep/wake cycle work?
- The SCN (E.P.) receives information about light levels (E.Z.) from the optic nerve.
- This sets the circadian rhythm so that it is in synchronisation with the outside world (e.g. day and night).
- The SCN sends signals to the pineal gland (E.P.)
- This leads to an increase in the production of melatonin (sleep hormone) at night, helping to induce sleep.
If there is a lack of natural light, what exogenous zeitgebar can substitute for it?
Social cues (e.g. meal time).
What are circadian rhythms?
Any cycle that lasts 24 hours.
What is an example of a circadian rhythm?
The sleep/wake cycle.