endogenous pacemakers +sleep wake

Question 1

The suprachiasmatic nucleus

Answer 1

tiny bundle of nerve cells located in hypothalamus in each hemisphere of the brain
- one of the primary endogenous pacemakers in mammals

Question 3

THE SCN coNNECTION TO OPTIC

Answer 3

nerve fibres connected to the eye in an area called the optic chiasm - it received information about light directly

Question 4

Decoursey

Answer 4

destroyed the SCN connections in the brain of 30 chipmunks who were then returned to their natural habitat and observed for 80 days - the sleep wake cycle of the chipmunks disappeared and by the end of the study, a significant proportion of them had been killed by predators (because they were active when they should have been sleeping)

Question 5

RALPH

Answer 5

bred mutant hamsters with a 20 hour sleep wake cycle - when SCN cells from the foetal tissue of mutant hamsters wee transplanted into the brains of normal hamsters, the cycles of the second group defaulted to 20 hours

Question 6

-animal studies

Answer 6

cannot be generalised

Question 7

-ethical concerns

Answer 7

harm to the animals
-affected natural habitat