biological rhythms infradian and ultra radian

Question 1

infradian rhythm

Answer 1

one complete cycle occurring less than once every 24 hours
entrained by exogenous Zeitgebers and endogenous pacemakers

Question 2

examples of infradian rhythms

Answer 2

menstrual cycle
SAD

Question 3

McClintock et al 1998
demonstrated menstrual cycle synchronisation amongst 29 women who all har irregular periods
he collected the

Answer 3

pheromones from 9 of the women through the use of a pad under the armpit , then rubbed on the upper lip of the remaining 20 women

Question 4

McClintock et al 1998
findings

Answer 4

found that recipients had shorter menstrual cycles when receiving the pheromones in the follicular phase of the menstrual cycles .

Question 5

SAD is an example of the influence of

Answer 5

endogenous pacemakers on the circadian sleep wake cycle

Question 6

SAD is an infradian disorder caused by disruption to the sleep wake cycle common in winter

Answer 6

as long nights means that more melatonin is secreted from the pituitary gland via the endocrine system , which changes the production of melatonin leading to feelings of loneliness and depression

Question 7

ultra radian rhythm

Answer 7

one complete cycle occurring more than once every 24 hours

Question 8

example of ultra radian rhythm

Answer 8

stages of sleep where a full sleep cycle takes 90 mins to complete

Question 9

stages of the sleep cycle

Answer 9

stage 1 and 2 represent the ‘sleep escalator’ when the participant can be easily woken
stage 3 and 4 coincide with deep and slower delta waves
stage 5 REM sleep
closely associated with dreaming and movement inhibition and sensory blockade

Question 10

dement and kleitman 1957
demonstrate stages of sleep , studied 33 adults where the caffeine and alcohol intake had been controlled to remove EV , using EEG scans the researchers found that

Answer 10

discrete periods of rapid eye movement potentials were recorded without exception during 126 nights of disturbed sleep . since participants were able to recall their dreams when awake , it was assumed that dreaming is associated with REM
clear evidence supporting the idea of a distinct set of sleep stages

Question 11

menstrual synchronisation is not always present in all female samples
Trevathan et al 1993
noted that no evidence of menstrual synchronisation in the all female participants used which suggest

Answer 11

that there are external variables which may affect the timing and duration of menstrual cycles
McClintock et al , did not account for these EV’s such as smoking , physical activity and alcohol consumption
raises doubts about the strength of the influence of pheromones , as an exogenous zeitgeber that can entrain infradian rhythms

Question 12

dispute over chemical and hormonal basis of SAD
Gloth et al 1999
found that when treating sufferers of SAD with either vitamin D or broad spectrum phototherapy , found that all receiving vitamin improved in all outcomes, phototherapy group showed no significant change in depression scale measure , specifically patients given the vitamin

Answer 12

improved by 74% in their depression measures , suggest that phototherapy is ineffective in treating SAD .
since phototherapy involves expose to bright light in order to increase the rate at which the pineal gland secretes melatonin , implies melatonin and serotonin levels have little part to play in SAD and in entrainment of circadian sleep wake cycles

Question 13

animal studies support the role of pheromones
the link between the pheromone release and animal behaviour has been extensively supported
for example Leo et al 2003 studied the effects of pheromonal signals in the olfactory bulb off mice and concluded that

Answer 13

mammals encode social and reproductive info by integrating vomeronasal sensory activity specific to sex and genetic makeup
suggesting that the endogenous pacemakers have a critical role in the entraining of biological rhythms in animals , findings can be generalised to humans