Endogenous Pacemakers

Question 1

Superchiasmatic nucleus

Answer 1

bundle of nerve cells in hypothalamus which maintain circadian rhythms
- nerve fibres from eye cross at optic nerve on way to R+LVF
- SCN is just above optic chiasm and receives info from it

Question 2

Decoursey et al

Answer 2

Destroyed SCN connection in 30 chipmunks in natural habitat
- observed for 80 days
- s/w cycle disappeared + many killed by predators

Question 3

Ralph et al

Answer 3

Bred hamsters with 20 hour s/w cycle then gave their SCN cells to normal hamsters who then developed a s/w cycle of 20 hours

Question 4

Pineal gland + melatonin

Answer 4

SCN passes info on day length to the pineal gland which increase the production of melatonin during the night

Question 5

AO3 - others influences

Answer 5

DAMIOLA ET AL - changing mice feeding patterns altered CR of liver cells for up to 12 hours leavin SCN unaffected

Question 6

AO3 - difficult to study

Answer 6

In everyday life EP + EZ interact so makes little sense to seperate
- the more researchers try to seperate the lower the validity