Biological rhythms

Question 1

What is a biological rhythm?

Answer 1

They have an important influence on the way in which body systems behave

Question 2

All biological rhythms are controlled by

Answer 2

endogenous pacemakers which are the internal body clock

Question 3

All biological rhythms are influenced by…

Answer 3

exogenous zeitgebers which are external changes in the environment

Question 4

What is an ultradian rhythm?

Answer 4

This is a cycle that lasts less than 24 hours e.g the stages of sleep which last approximately 90 minutes

Question 5

What is a circadian rhythm?

Answer 5

This is a cycle that lasts for 24 hours e.g body temperature and the sleep wake cycle

Question 6

What is an infradian rhythm?

Answer 6

This is a cycle that lasts more than 24 hours e.g the female menstural cycle which operates appeoximately on a 28 day cycle

Question 7

What are circadian rhythms controlled by?

Answer 7

They are controlled by endogenous pacemakers which are internal factors that help us maintain bio rhythms

Question 8

What is the endogenous pacemaker in circadian rhythm?

Answer 8

Suprachiasmatic nucleus

Question 9

What are circadian rhythms also influenced by?

Answer 9

Exogenous zeitgebers which are external fators which are in our environment which can influence the sleep wake cycle

Question 10

Exogenous zeitgebers influence the sleep wake cycle?

Answer 10

Entertainment such as light which resets the SCN suggesting our sleep wake cycle is not only influenced by endogenous pacemakers

Question 11

What social cues can also influence the sleep/wake cycle?

Answer 11

Meal times and social interaction as our evening meal makes us less alert

Question 12

What is the sleep/wake cycle controlled by?

Answer 12

The master endogenous pacemaker, the suprachiasmatic nucleus

Question 13

What do our eyes notice?

Answer 13

Our eyes notice a change in light as it gets dark and less light is recieved by the retina

Question 14

Less light recieved by the retina results in…

Answer 14

information being sent to the SCN which stimulates the pineal gland to release melatonin and promote sleep

Question 15

When our eyes detect light again…

Answer 15

the SCN is reset which stimulates the SCN and pineal gland which inhibits the release of melatonin to promote wakefulness. This suggests the sleep wake cycle is controlled by endogenous factors

Question 16

Biological rhythms can be affected by…

Answer 16

exogenous zeitgebers and these can make it difficult to maintain a constant cycle

Question 17

When these external factors overide our natural rhythm…

Answer 17

it can lead to disruption =, which can have a range of consequences

Question 18

Why may the sleep wake cycle be disrupted?

Answer 18

Jet leg (especially when traveling West to East) and through shift work

Question 19

What negative consequences can the disruption of the sleep wake cycle cause?

Answer 19

-Difficulty in sleeping
-Decreased attention leading to accidents
-Digestive problems
-Tiredness and poorer reasoning skills
-Increased anxiety and irritability

Question 20

How can we maintain our sleep wake cycle?

Answer 20

Keep to local times when eating, keep to local times for sleeping e.g sleeping when its dark, stimulation during the day, black out curtains, limiting phones and screens

Question 21

What are infradian rhythms?

Answer 21

They are biological rhythms that last longer than 24 hours.

Question 22

What is one example of an infradian rhythm?

Answer 22

The female menstural cycle

Question 23

What does the female menstural cycle operate on?

Answer 23

It operates on a 28-35 day cycle and the rhythm is regulated by glands and hormones

Question 24

What factors are infradian rhythms influenced by?

Answer 24

Endogenous factors and exogenous zeitgebers

Question 25

When does the menstural cycle begin?

Answer 25

On the first day of a woman's period, when the womb lining is shed to the day before her next period

Question 26

What does the brain release?

Answer 26

It releases FSH which activates the release of oestrogen from the ovaries and causes the egg to mature

Question 27

What happens in the middle of the infradian rhythm?

Answer 27

The increase of oestrogen increases levels of LH which promotes the release of an egg

Question 28

What does oestrogen develop?

Answer 28

It develops the lining of the womb and progesterone helps it grow thicker, readying the womb for pregnancy

Question 29

What happens at the end of the menstural cycle?

Answer 29

If pregnancy does not occur, the egg is absorbed into the body, the womb lining comes away and leaves the body and the cycle begins again

Question 30

Although the menstural cycle is mainly an endogenous system...

Answer 30

which is regulated by the pituitary gland and the hormones of oestrogen and progesterone

Question 31

What exogenous zeitgebers can also influence the menstural cycle?

Answer 31

Light, stress and pheromones which can lead to inconsistent infradian rhythm

Question 32

What is an ultradian rhythm?

Answer 32

An ultradian rhythm is a biological rhythm that occurs more frequently than once every 24 hours

Question 33

What is an example of an ultradian rhythm?

Answer 33

One example of the stages of sleep which occurs more frequently than once eveery 24 hours as there are 5 distinct stages of sleep that a person cycles through up to 5 times a night

Question 34

Research, using EEG into ultradian rhythms has shown...

Answer 34

there are 5 distinct stages of sleep

Question 35

what are the 5 distinct stages of sleep characterised by?

Answer 35

differences in brain, muscle and eye activity during NREM and REM sleep stages

Question 36

It is argued that ultradian rhythms are under what control?

Answer 36

Under endogenous control as there are 5 different stages of sleep which last 90 minutes each

Question 37

What happens during stages 1 and 2 of sleep?

Answer 37

This is a light sleep where a person may be easily woken and show alpha brain waves

Question 38

What happens during stages 3 and 4 (NREM) of sleep?

Answer 38

This is known as deep sleep and brain waves are delta waves. It is difficult to wake someone at this point. The body repairs muscles in stage 4

Question 39

What hapoens during stage 5 REM sleep?

Answer 39

The body is paralysed and brain activity closely resembles that of the awake brain. Dreams are often experienced in this stage and the function of stage 5 sleep is to repair the brain e.g replenish neurotransmitter levels

Question 40

However, there's evidence into ultradian rhythms which shows the role of...

Answer 40

exogenous zeitgebers that can impact the consistency of ultradian rhythms

Question 41

How does excersise affect ultradian rhythms?

Answer 41

Individuals who run ultra-marathons spend longer in stage 4 of sleep which has been found to aid physical recovery

Question 42

How do mental health conditions act as an exogenous factor?

Answer 42

Individuals with depression have been found to enter stage 5 earlier than the average person and will show inceased REM sleep duration