Exogenous Zeitbegers Flashcards
Define Exogenous Zeitbeger
Provide 3 examples
These are external environmental cues or events that influences and synchronises an organism’s internal biological clock. E.g, light, temperature, social cues
Define Zeitbeger
Rhythmically occurring natural phenomena’s which acts as a cue in the regulation of the body’s biological rhythms
What are the three steps to how the exogenous zeitbeger of light is involved with the body’s SCN?
- Light is detected in the retina by a third type of cell called ‘light detecting cells’
-These cells then synchronise the rest of the body
-This process trains the SCN, which controls the circadian rhythms in the body, and resets it.
What are the three type of cell in exogenous zeitbegers?
‘Light detecting cells’
‘rod cells’
‘cone cells’
What is contained in the ‘light detecting cells’ within the retinas and what does it do?
The cells contain melanopsin, which detects the level of light and sends the message to the SCN
What did Burgess et al. (2003) conduct a field experiment on and what was the aim?
They tested the impact of shining light on ppts before they took a flight (going east from west)
Aim- to see if the light would reduce jet lag
What were the three groups Burgess et al. (2003) included in their field experiment? (regarding light and flights)
-Continuous bright light
-Intermittent bright light
-Dim light
What was the main result from Burgess et al.’s (2003) field experiment that regards the group of Continuous bright light?
This group had the best outcome as their rhythms shifted closer to their destinations by two hours.
What did Vetter et al.’s (2011) ‘blue light experiment’ involve?
They conducted a blue light experiment where they studied the impact of natural daylight bulbs and bulbs that gave a lot of blue spectrum light.
Over a period of five weeks, what were the two results from Vetter et al.’s (2011) blue light experiment? (Natural daylight result, blue light bulb result)
- Ppts with natural daylight bulbs had better synchronisation with the real world rhythm.
-Those with blue light bulbs ended up with a circadian rhythm out of sync with the real world rhythm
What do the results of Vetter et al.’s (2011) ‘blue light experiment’ support and suggest?
Supports the role of light being an EZ
Suggests light sources with a high blue content can help to desynchronise our internal rhythms from the daylight rhythms.
What is the main alternative Exogenous zeitbeger?
explain the example of eating.
Social cues, e.g such as when people eat.
Eating resets the stomach and the liver which can have a large influence on other biological rhythms.
What advice is often given to travellers who suffer from jet lag?
-Make sure they eat at the right times when they get to their destination as it will help their body to adapt more quickly to the new daily rhythm.
Define beta bias
This is when both groups are treated as the same, e.g race and gender.
What did Campbell and Murphy (1998) find regarding shining light at somewhere and what does this suggest?
They found if you shine a light on the back of someone’s knees, it can influence their circadian rhythm.
Suggests circadian rhythms can be disrupted by low light levels.
What did Shih-Yo Lee et al. (2013) find regarding light therapy and mothers?
Found that light therapy can help mothers of premature babies adapt to intensive care where there is low level light all night, which disrupts the mother’s sleep.
