Circadian Rhythms Flashcards
What are biological rhythms
They are distinct patterns of changes in body activity to confirm cyclical time periods
What are biological rhythms influenced by
Endogenous pacemakers and exogenous zeigetbergs
What are endogenous pacemakers
Internal body clocks
What are exogenous zeigetbergs
External changes to the environment
What are circadian rhythms
Biological rhythms that are subject to a 24 hour cycle which regulates a number of bodily processes
What are two examples of circadian rhythms
Sleepwalk cycle and core body temperature
What endogenous pacemaker is the sleepwake cycle governed by
The Suprachiasmatic nucleus
What is the suprachiasmatic nucleus
It’s the biological clock which regulates sleep wake cycle
Where is the suprachiasmatic nucleus located
It lies just above the optic chiasm
How does the suprachiasmatic nucleus work with the optic chiasm
Provide information from the eye about light
What is the exogenous zeitgeber in the process of scn
Light
What does the exogenous zeitgeber (light) do for the SCN
Resets the SCN
What is the main study for the sleepwake cycle and circadian rhythm
Saffres cave study
What do researchers refer to as free running in terms of the sleepwake cycle
No influence of external stimulus such as light
How did Siffre study his biological rhythm
He spent several extended periods underground to study that affects of his own biological rhythm
What did Siffre deprive himself of and allow himself to have during his study on biological
Deprived himself of natural light and sound
Allowed himself to have adequate food and drinks
When Siffre resurfaced what time of the year did he think it was and what was the reality
He thought it was mid August when it was actually mid September
How long did Siffre stay in the Southern Alps cave
2 months
When he performed a similar fee a decade later what changes did he make
Instead of saying in the cave for two months he said for six months and instead of the Southern Alps he stayed in a Texan cave
What researcher had similar results shown with Siffre
Aschoff and Wever
How was aschoffs and Wevers study conducted
They convinced a group of participants to spend four weeks in a world war two bunker which was deprived of natural light
What were the findings of aschoffs and Wevers research
All but one of the participants display the circadian rhythm between 24 and 25 hours (the anolomaly was 29 hours)
What did the two cave and bunker studies show about the sleep week cycle
It suggests that the natural sleepwake cycle may be slightly longer than 24 hours but that is entrained by exogenous zeitgeber associated with our 24-hour day
What was Folkards aim of his study
To study how we should not overestimate the influence of exogenous zeiterbergs on our internal biological clock
How did Folkard conduct his study
He studied a group of 12 people who agreed to live in a dark cave for three weeks going to bed when the clock said 11:45 p.m. and waking up when it said 7:45 a.m.
What did the researchers of Folkards research change over the course of the study
They gradually started to speed up the clock unknown to the participants so that a 24 hour day would eventually be 22 hours
What was the result of folk art study
Only one of the participants was able to comfortably adjust to the new change which suggests that the existence of a strong free running circadian rhythm can’t be easily overridden by exogenous zeitgebers
How does core body temperature vary over the course of a day
If I is the lowest around 4:00 a.m. where it’s at 36 degrees Celsius and peaks around six pm at 38 degrees Celsius
What does evidence suggest about body temperature and is correlation with mental abilities
The warmer we are internally the better our cognitive performance
How did Folkard study the effect of body temperature on mental abilities
You demonstrated how children who had stories read to them at 3 p.m. showed superior recall and comprehension after a week compared to children who heard the same stories at 9:00 a.m.
How did Gupta study the effects of body temperature on mental abilities
She found improved performance on IQ test when participants were assessed at 7:00 p.m. as opposed to 2pm and 9:00 a.m.
