L12.1 - Endogenous Pacemakers

Question 1

Define endogenous pacemakers

Answer 1

Internal biological rhythms which are reset every day

Question 2

Define exogenous zeitgebers

Answer 2

External factors like light that reset our biological rhythms every day

Question 3

Role of SCN

Answer 3

Links brain regions which control sleep and arousal

Controls other biological clocks in the body

Question 4

SCN neurons interact how

Answer 4

Synchronise with each other

Question 5

SCN’s circadian rhythm needs resetting when?

Answer 5

When external light levels change

Morning light shifts clock if slow

Question 6

SCN also regulates what chemical

Answer 6

Manufacture and release of melatonin from pineal gland

Question 7

Peripheral clocks can maintain what?

Answer 7

Circadian rhythm but not for long

Question 8

+ related to hamsters

Answer 8

SCN neurons from hamsters with abnormal circadian rhythms of 20 hrs was transplanted into brain of hamsters who subsequently displayed same abnormal circadian rhythm

Question 9

+ related to Kate Aldcroft

Answer 9

Spent 25 days in lab without natural light of any EZs

Core temp rhythm was still at 24 hrs by the end

Question 10

• related to Kate Aldcroft

Answer 10

Sleep-wake cycle extended to 30 hours

Slept for as long as 16 hours