Biopsychology Flashcards
How long does a circadian rhythm last?
24 hours
What are circadian rhythms driven by?
Our body clocks, which are synchronised by our SCN in the hypothalamus
How is our body clocks set?
Light - through the brightness detectors in the eye
Two examples of circadian rhythms
Sleep wake cycle
Body temperate
What else is the sleep wake cycle determined by ?
Homeostatic control- tells us When we need sleep due to the amount of energy used being awake
What can affect the sleep wake cycle ?
Jet lag
Shift work
How is body temperature a circadian rhythm?
Lowest temperature is around 4:30am 36 degrees (starts increasing from this point )and the highest is at 6pm( starts decreasing) at 38 degree. Increase temperate in the morning promotes alertness
What did the case study of stiffe prove about circadian rhythms?
Living underground with no external cues and sleeping when he liked. On his first stay of 60 days he believed it was August 20th however it was 17th September showing external factors help regulate the circadian rhythm
Strengths of circadian rhythms
Practical application- helped show when patients should take medication to be most effective
Weaknesses of circadian rhythms
Cycle can vary 13-65 hours - individual differences
May be the temperate that controls body clock and not light as it fluctuates
Artificial lighting may impact the rhythm- czeisler down to 22hrs or up to 28 hrs
How long do infradian rhythms last?
Longer than 24 hours (days, weeks, months, annual )
Two examples of infradian rhythms
Menstrual cycle
Seasonal moods
How is the menstrual cycle a infradian rhythm ?
It lasts usually 28 days but can be anywhere from 23-36 days
Hormone regulated for fertilisation
After ovulation, progesterone increases for implantation of embryo
How are seasonal mood changes infradian rhythm?
Humans moods change based on the seasons.
Magussan found that especially women experience season affective disorder- being more depressed in winter
How long do ultradian rhythms last ?
Less than 24 hours
How many stages of sleep are there? And which stage is REM
There are 4 stages of NREM (non rapid eye movement) and the 5th stage is REM
How long does the sleep cycle last?
90 minutes and repeats through the night.
How do we observe/ monitor the sleep cycle ?
EEG’s
What happens to the body in deep sleep?
Decreased breathing
Brainwaves slow
Decrease in heart rate
How does Keitman support ultradian rhythms ?
Referred to the cycle as BRAC ( basic rest activity cycle ) continues through the day between alertness to fatigue which leads to lack of concentration
What supporting evidence is there for ultradian rhythms?
Ericsson found that violinist practice sessions are limited to 90 minutes and they frequently napped to recover.
What weakness are there of both infradian and ultradian rhythms ?
External factors such as room temperature and sleep hygiene may effect sleep patterns
Menstrual cycle is usual endogenous however it can be exogenously controlled through synchronisation through groups of women.
What is the animal research into circadian rhythms?
DeCoursey - behaviour of SCN lesioned chipmunks
30 chipmunks
Removed the SCN returned home.
After 80 days many died compared to control group
Circadian rhythms aid survival
What did McClintock find on infradiam rhythms ?
Students who lived in university halls tended to synchronise their menstrual cycle
How did Wilson criticise McClintock ?
The length of the cycle means friends will have an overlapping period.
What did Dement and Kleitman research ?
Ultradian rhythms
7 males and 2 females
Avoid alcohol and caffeine
Monitored on EEG
Several stages of REM
