Endogenous and exogenous essay Flashcards
What is the SCN ?
It’s the pacemaker of the biological clock in the sleep wake cycle
How does the SCN generate its own innate biological rhythm ?
By protein synthesis
What is the SCN connected to?
The optic chiasm
What role does the optic chiasm play, in terms of influencing the biological rhythm ?
It receives input about the amount of light (exogenous factor), which stimulates nerve impulses that travel from the eye along the optic nerve to the brain
How is the pineal gland linked to the SCN
By a neural pathway
What causes the release of melatonin?
An electrical stimulation of the SCN that is transferred to the pineal gland
Describe the relationship between light and melatonin
Light and melatonin are inversely proportional so when light levels are low melatonin levels are high
How does melatonin induce sleep?
It enhances the production of serotonin which causes the nervous system to slow down, brain activity falls
What did Morgan’s research show?
The research showed that the SCN is the dominant biological clock in mammals
What happened when Morgan removed the SCN from hamsters?
Their nocturnal Circadian rhythms disappeared
which study demonstrated the importance of light ?
Miles raynal and Wilson study of a blind man
How long was the blindmans circadian rhythm
24.9
What did the consistency of the blind mans circadian rhythm support?
It supports a biologically determined endogenous rhythm despite the absence of the main time giver light. However also supports the idea that light is important as his rhythm was extended
How long did siffres circadian rhythm extend by?
1 hour
How long was siffre in the cave?
2 months
Siffre developed a 25hour rhythm however wasn’t way off the normal rhythm what does this support ?
It supports the idea of an innate biologically determined rhythm
Who reported a case study of a young woman
Folkard 1996
How long was Kate Aldcroft isolated for?
25 days
What do biological rhythms need to be fine tuned by?
Exogenous zeitgebers
What is the dominant exogenous zeitgeber in humans?
Light
What can light do to the pacemaker?
Light can reset the pacemaker SCN and also reset other internal clocks such as the CRY
what does the CRY stand for?
Crytochrome
What did Campbell and Murphy 1998 find?
They found that if you shine light on the back of participants knees this shifted their circadian rhythms
Who conducted a 10 year longitudinal study?
McClintock and stern
68% of the women responded to the pheromones of other women
True or false
True
What happened to the menstrual cycle of these women?
Their menstrual cycle altered according to when during the cycle the pheromone had been taken
What does the SCN stand for?
The suprachiasmatic nucleus
How is our internal world connected and informed about the external world
Via our senses
Who conducted a study on 135 female dorm mates ?
McClintock
