Biological rhythms: infradian and ultradian rhythms AO1

Question 1

What is the menstrual cycle?

Answer 1

The menstrual cycle is the time between the first day of a woman’s period and the day before her next period, typically lasting about 28 days.

Question 2

What hormones regulate the menstrual cycle?

Answer 2

Estrogen and progesterone.

Question 3

What occurs during ovulation?

Answer 3

The ovary develops and releases an egg.

Question 4

What happens to the womb lining after ovulation if pregnancy does not occur?

Answer 4

The egg is absorbed, and the womb lining sheds, resulting in menstrual flow.

Question 5

What is an example of an infradian rhythm?

Answer 5

The menstrual cycle: it’s governed by monthly changes in hormone levels which regulate ovulation

Question 6

What is the typical duration range for a menstrual cycle?

Answer 6

24 to 35 days.

Question 7

What evidence suggests menstrual cycles may synchronize among women?

Answer 7

• Studies indicate that pheromones may influence the synchronization of menstrual cycles.
• although the menstrual cycle is an endogenous system, evidence suggests that it may be influenced by exogenous factors such as the cycles of other women

Question 8

What was the key finding of Stern and McClintock’s study on menstrual cycles?

Answer 8

• they studied 29 women with a history of irregular periods. Samples of pheromones were gathered from nine of the women at different stages of their menstrual cycle via a cotton pad placed in their armpit.
• the pads were worn for at least 8 hours to ensure that pheromones were picked up. The pads were then treated with alcohol and frozen, to be rubbed on the upper lip of the other participants.
• on day one pads from the start of the menstrual cycle were applied to all 20 women, on day two they were all given a pad from the second day of the menstrual cycle and so on
• found that 68% of women experienced changes to their cycle that brought them closer to their ‘odour donor’s’ cycle.

Question 9

What is Seasonal Affective Disorder (SAD)?

Answer 9

A depressive disorder characterized by seasonal patterns of onset, often triggered in winter.
- mental disorder in DSM-5

Question 10

What are the main symptoms of SAD?

Answer 10

Persistent low mood, lack of activity, and loss of interest in life.

Question 11

Why is SAD referred to as the winter blues?

Answer 11

Symptoms are triggered during winter months with shorter daylight hours.

Question 12

What type of rhythm is SAD classified as?

Answer 12

a type of infradian rhythm called Circannual rhythm as it is subject to a yearly cycle. However it can also be classed as a circadian rhythm as the experience of SAD may be due to the disruption of sleep/wake cycle and this can be attributed to prolonged periods of daily darkness during winter

Question 13

How can SAD also be considered a circadian rhythm?

Answer 13

It can result from disruptions in the sleep/wake cycle due to prolonged darkness.

Question 14

Which hormone is hypothesized to be involved in SAD?

Answer 14

Melatonin.

Question 15

What is the role of melatonin in the context of SAD?

Answer 15

Melatonin secretion continues longer during winter due to less morning light.
- secretes by the pineal gland

Question 16

What effect does prolonged melatonin secretion have on serotonin?

Answer 16

It is thought to negatively impact serotonin production, linked to depressive symptoms.

Question 17

What are ultradian rhythms?

Answer 17

Biological rhythms with a frequency of more than one cycle in 24 hours such as stages of sleep

Question 18

How many stages of sleep are identified in the sleep cycle?

Answer 18

Five distinct stages.

Question 19

What is the duration of one complete sleep cycle?

Answer 19

Approximately 90 minutes.

Question 20

What type of brain activity is monitored during sleep?

Answer 20

different level of Brainwave actuvity which can be monitored using an EEG.

Question 21

What characterizes stages 1 and 2 of sleep?

Answer 21

STAGE 1
- Light sleep with easily woken individuals
- alpha waves.
- brain waves are high in frequency and have a short amplitude

STAGE 2
- the alpha waves continue but there are occasional random changes in pattern called sleep spindles.

Question 22

What are sleep spindles?

Answer 22

Occasional random changes in brain wave pattern of alpha waves during stage 2 sleep.

Question 23

What is deep sleep also known as?
- what sleep stage is this found in

Answer 23

• Slow wave sleep (SWS).
• stage 3/4

Question 24

What type of brain waves are present during stages 3 and 4?

Answer 24

• Delta waves
• lower frequency and higher amplitude.
• it’s difficult to wake someone in this point

Question 25

Is it easy or difficult to wake someone in stages 3 and 4?

Answer 25

Difficult.

Question 26

What occurs during stage 5 of sleep?

Answer 26

REM sleep where the body is paralysed but brain activity resembles waking.

Question 27

What type of waves does the brain produce during REM sleep?

Answer 27

Theta waves.

Question 28

What is the significance of rapid eye movement (REM) in sleep?

Answer 28

It is associated with dreaming.

Question 29

Dreams are most often experienced during which stage of sleep?

Answer 29

REM sleep.

Question 30

Fill in the blank: The sleep cycle continues throughout the course of the _______.

Answer 30

[night].

Question 31

what is an Infradian rhythm

Answer 31

a type of biological rhythm with a frequency of less than one cycle in 24 hours, such as menstruation and seasonal affective disorder