Endogenous pacemakers and exogenous zeitgebers evaluation

Question 1

What are the ethical issues with the animal studies?

Answer 1

The animals were exposed to harm when they returned to their natural environment
Whether what we learn justifies the procedure is a matter of debate

Question 2

What were the methodological issues with the studies?

Answer 2

The findings of campbell and Murphy are yet to be replicated
It is suggested that there was limited light exposure in the studies , a major confounding variable - isolating one exogenous zeitgeber does not give an insight into the others

Question 3

What is another issue with the studies?

Answer 3

Only in exceptional circumstances are endogenous pacemakers free running and unaffected by the influence of exogenous zeitgebers. Total isolation studies are rare and could lack validity - in real life pacemakers and zeitgebers interact so it makes little sense to separate the two for studies

Question 4

How many the influence of exogenous zeitgebers be overstated?

Answer 4

Miles et al researched a young man who was born blind with a 24.9 hour cycle and despite exposure to social cues his sleep/wake cycle could not be adjusted and he had to take stimulants and sedatives
People who live in artic regions show normal patterns even though they have prolonged exposure to light
Demonstrating exogenous zeitgebers have little bearing on internal rhythm

Question 5

Where are there circadian rhythms?

Answer 5

In many organs and cells in the body, these are called peripheral oscillators and are found in the adrenal gland, oesophagus, liver lungs and skit etc and although influenced by the SCN can act independently

Question 6

What was Damiola’s research?

Answer 6

Demonstrated how changing feeding patterns in mice could alter the circadian rhythm of cells in the liver for up to 12 hours leaving the rhythm of the SCN unaffected suggesting there may be more complex influences on sleep