Endogenous pacemakers and exogenous zeitgebers
Endogenous pacemakers = internal body clock that regulates biological
rhythms
Exogenous zeitgebers = external factors which entrain our biological clock
Role of endogenous pacemakers in the sleep/wake cycle – SCN is our internal
biological clock which transfers messages to the pineal gland about if day or
night, which the pineal gland will then regulate melatonin. If no sunlight pineal
gland will produce melatonin.
Studies to support the role of the SCN:
Decoursey destroyed connections to the SCN in 30 chipmunks and returned
them to their natural habitat. Observed them for 80 days. their s/w cycle
disappeared and significant amount of them was killed due to change in
sleeping patterns. Shows SCN key role in establishing a s/w cycle.
Ralph – bred mutant hamsters to have a 20 hour sleep/wake cycle.
Transplanted DNA into normal hamsters. They also defaulted to a 20 hour s/w
cycle. Supports the role of SCN in establishing biological rhythms.
Exogenous zeitgebers
External factors which entrain our biological rhythms.
Light – can reset the SCN. Campbell and Murphy also found that light can be
detected by skin receptors e.g. on the back of the knee, causing a response
from a person.
Social cues – 6 weeks baby develop a s/w cycle. 16 weeks their s/w cycle is
entrained by their parents.
Ao3:
Endogenous pacemakers = internal body clock that regulates biological
rhythms
Exogenous zeitgebers = external factors which entrain our biological clock
Role of endogenous pacemakers in the sleep/wake cycle – SCN is our internal
biological clock which transfers messages to the pineal gland about if day or
night, which the pineal gland will then regulate melatonin. If no sunlight pineal
gland will produce melatonin.
Studies to support the role of the SCN:
Decoursey destroyed connections to the SCN in 30 chipmunks and returned
them to their natural habitat. Observed them for 80 days. their s/w cycle
disappeared and significant amount of them was killed due to change in
sleeping patterns. Shows SCN key role in establishing a s/w cycle.
Ralph – bred mutant hamsters to have a 20 hour sleep/wake cycle.
Transplanted DNA into normal hamsters. They also defaulted to a 20 hour s/w
cycle. Supports the role of SCN in establishing biological rhythms.
Exogenous zeitgebers
External factors which entrain our biological rhythms.
Light – can reset the SCN. Campbell and Murphy also found that light can be
detected by skin receptors e.g. on the back of the knee, causing a response
from a person.
Social cues – 6 weeks baby develop a s/w cycle. 16 weeks their s/w cycle is
entrained by their parents.
Ao3:
