Biopsychology: Biological Rhythms (Circadian, Infradian & Ultradian) Flashcards
What is an ultradian rhythm with an example?
A cycle less than 24 hours e.g. the stages of sleep
Define the term circadian rhythm and give an example.
A cycle that lasts for 24 hours e.g. sleep-wake cycle
Define the term infradian rhythms and give an example.
A cycle that lasts longer than 24 hours e.g. the menstrual cycle
What is meant by the term endogenous pacemaker?
Internal body clock
What is meant by the term exogenous zeitgeber?
External factors that influence the body clock
Name the main endogenous pacemaker in the sleep-wake cycle.
Suprachaismatic Nucleus (SCN)
In the sleep wake cycle, when it goes dark less light is received by the …
Retina
What does the SCN stimulate?
The pineal gland
What is released by the pineal gland to promote sleep?
Melatonin
Name an exogneous zeitgeber is the sleep-wake cycle
Light
Clocks
Siffre spent six months in a cave. What happened to his circadian rhythm?
It went from 24 hours to a 25 hour cycle
What is a problem with Siffre’s research?
Low population validity - case study
Lacks ecological validity - unlike real life
Explain what Wever did and why it supports Siffre.
Wever conducted research over 400 times where people were in an underground bunker with a free running rhythm
Supports Siffre as they developed a 25 hour cycle showing role of endogenous factors
How long does the menstrual cycle last?
28-35 days
What happens on the first day of the menstrual cycle?
Womb lining is shed
What does the pituitary gland release during the menstrual cycle?
FSH
FSH leads to the release of which hormone?
Oestrogen
An increase in oestrogen leads to increased?
LH
What does Oestrogen and progesterone do in the menstrual cycle?
Oestrogen - develops the lining of the womb
Progesterone helps it grow thicker
What happens to the egg if pregnancy does not occur?
Egg is absorbed into the body
Name two exogenous factors that can influence the menstrual cycle.
Stress
Pheromones
Define the term pheromones.
Chemical scent
What did Russell find?
4 out of 5 women synchronised their cycle to within one day of the donor due to pheromones.
Explain one problem with Russell’s research on infradian rhythms
Low control - other factors such as light could have affected the rhythms not just pheromones
Why is synchronising cycles beneficial?
If many women are breast feeding at the same time, one mother could take over care of an orphaned child.
How many stages of sleep are there?
5 stages
Which way of studying the brain is used to study sleep?
EEG
In stage 1 and 2 which brain waves are identified?
Alpha
What occurs only is stage 2?
K-complex
Sleep Spindles
Which waves are released in stage 3 and 4?
Delta
What can be said about the body in REM sleep (stage 5)?
Paralysed
Which waves are identified in REM (stage 5)?
Theta
In which stage do dreams most likely occur?
Stage 5 (REM)
What has research shown about stage 4 sleep in old age?
People in old age have less stage 4 sleep so can learn relaxation techniques or take medication to increase stage 4 sleep.
Why can research into ultradian rhythms be argued to use scientific methods.
EEG’s are objective and empirical methods and sleep labs are controlled.
Why can it be argued that sleep labs have low ecological validity?
Sleep labs are an artificial setting and due to the unfamiliar surroundings and being attached to electrodes may not reflect sleep stages in the real world.
Name two ways biological rhythms can be disrupted?
Jet lag
Shift work
What can happen when sleep-wake cycle is disrupted?
Difficulty in sleeping
Decreased attention
Digestive problems
Tiredness and poor reasoning skills
Increased anxiety and irritability.
How can a person maintain their sleep wake cycle?
Keep to local time for eating and sleeping
Stimulate yourself during the day
Use black out curtains at night
Not using phones and screens late at night.
What did the researchers do to the chipmunks in DeCoursey’s research?
Destroyed connections to the SCN
What happened to the chipmunks due to their SCN being destroyed?
Sleep wake cycle disappeared
A significant proportion had been killed by predators
What is a limitation for DeCoursey’s research?
Animal bias - humans may have more complex biological rhythms so harder to generalise from animal to humans
