Biological rhythms: Infradian and ultradian rhythms

Question 1

Infradian rhythm

Answer 1

type of biological rhythm with a frequency less than one cycle in 24 hours, such as menstruation and seasonal affective disorder. They take longer than 24 hours to complete

Question 2

Ultradian Rhythm

Answer 2

Type of biological rhythm with a frequency of more than one cycle in 24 hours. Takes less than 24 hours to complete

Question 3

Stern and McClintock

Answer 3

Demonstrated how menstrual cycles may synchronise as a result of the influence of female pheromones. Involved 29 women with history of irregular periods. They gathered pheromones from 9 women at different stages of their period via cotton pad placed in their armpit. Pads were worn for 8 hours and treated with alcohol and frozen to be rubbed on the upper lip of the other ppts

Question 4

Findings of McClintock’s study

Answer 4

Found that 68% of women experienced changes to their cycle which brought them closer to the cycle of their odour donor.

Question 5

Seasonal affective disorder

Answer 5

Is a depressive disorder and is stated as a mental disorder in DSM-5.

Symptoms=low mood and lack of activity

SAD is often referred to as the winter blues as symptoms are triggered due to number of daylight in winter. Experiences of SAD can also be classified as a circadian rhythm as it can be due to disruption of sleep/wake cycle.

Question 6

How does melatonin link to SAD

Answer 6

Pineal gland secretes melatonin until dawn when there is a increase in light. In winter due to lack of light. So Secretion of melatonin is longer. This then has a knock-on effect on serotonin which has been linked to depression.

Question 7

Stages of the sleep wake cycle (ultradian rhythms) stage 1 and 2

Answer 7

light sleep where the person can be easily woken. At the beginning of sleep the brain emits alpha waves which become even slower as sleep becomes deeper. (theta waves)

Question 8

Stages of the sleep wake cycle (ultradian rhythms) stage 3 and 4

Answer 8

Delta waves which are slower and have greater amplitude than earlier waves. Identified as deep sleep or slow wave sleep and it is difficult to wake person up.

Question 9

Stages of the sleep wake cycle (ultradian rhythms) stage 5

Answer 9

REM sleep- body is paralysed but brain activity speeds up. REM stands for rapid eye movement. Jerky activity of the eyes under eyelids. REM is highly correlated with dreaming