Endogenous Pacemakers and Exogenous Zeitgebers Flashcards
What are endogenous pacemakers?
Internal body clocks that regulate biological rhythm
What is the superchiasmatic nucleus (SCN)?
Bundle of nerve cells
Where is the SCN located?
Hypothalamus
What is the SCN linked with?
The sleep/wake cycle
What is the SCN connected to?
Optic chiasm
What does the SCN receive?
Light directly when the eyes are closed
Which two psychologist researched into the sleep/wake cycle?
- Decoursey et al
- Ralph et al
What did Decoursey et al (2002) do?
- Destroyed SCN connection in 30 chipmunks
- Returned them to natural habit and observed
What did Decoursey et al (2000) find?
Sleep/wake cycle disappeared and majority killed after 80 days
What did Ralph et al (1990) do?
- Bred hamsters with 20 hour sleep/wake cycle
- SCN of mutant hamsters transplanted into normal hamsters
What did Ralph et al (1990) find?
Normal hamsters developed a 20 hour sleep/wake cycle
What is the SNC an example of?
Endogenous pacemaker
What are the three examples of endogenous pacemaker?
- SCN
- Pineal gland
- Melatonin
How is SCN linked to the pineal gland and melatonin?
SCN passes information on day length to pineal gland which increases secretion of melatonin during the night
What does melatonin induce?
Sleep