Biopsych L10-12

Question 1

What are biological rhythms?

Answer 1

Cyclical changes in physiological systems

Question 2

What are the three types of biological rhythms?

Answer 2

Circadian
Ultradian
Infradian

Question 3

How long circadian rhythms last?

Answer 3

24 hours

Question 4

What controls circadian rhythms?

Answer 4

Suprachiasmatic nuclei in hypothalamus that acts as a pacemaker

Question 5

What does a pacemaker do?

Answer 5

It constantly resets to make sure the body is in sync with the world

Question 6

What sets the SCN and how?

Answer 6

Natural light

Via photo entrainment

Question 7

What controls the sleep wake cycle?

Answer 7

Its under homeostatic control

And it increases gradually during the day

Question 8

What is the pineal gland responsible for in circadian rhythms?

Answer 8

Releasing melatonin during darkness

Question 9

What does melatonin do?

Answer 9

Induces sleep

By inhibiting neural mechanisms that promote wakefulness

Question 10

Strengths or circadian rhythms

Answer 10

+ practical application (chrono therapeutics)

Time that meds are taken are important for success as it indicates release

(Heart attack likely 6:00 am so meds taken before sleep to be released roughly at the right time)

Question 11

Weaknesses of circadian rhythms

Answer 11

• individual differences (cycles vary from 13-165hrs)

-Arctic, show normal sleeping patterns
But exogenous zeitgeist of light has little influence on internal biological rhythms

• people peak differently (morning vs evening people)
• Cziesler altered someones c.rhythm down to 22hrs and 28hrs using artificial light

Question 12

How long is ultradian rhythms?

Answer 12

Less than 24 hours

Repeats every 90 mins

Question 13

What are the five stages of ultradian rhythms?

Answer 13

1-4: non rapid eye movement

5: rapid eye movement

Question 14

What does the EEG during stage 5 of ultradian rhythms look like?

Answer 14

The eeg resembles an awake person where dreaming happens

Question 15

What is the 90 minutes of the ultradian called?

Answer 15

Basic rest activity cycle

Question 16

What did kleitman say about ultradian rhythms?

Answer 16

Applies even during the day

Stage of alertness is physiological fatigue and it happens towards the end of the ninety minutes

Question 17

What is the evaluation of ultradian rhythms?

Answer 17

+ Ericsson studied elite violinists do 90 mins practicing then napping
They did better
It fits with BRAC

-individual differences
Pps studied for 11 days straight
Differences in when and for how long they sleep

Question 18

How long are infradian rhythms?

Answer 18

Longer than 24 hours

Question 19

Give an example of an infradian cycle

Answer 19

Menstrual

Question 20

Strength of Infradian rhythms

Answer 20

+ affects behaviour
Women like more feminised male faces for LT relationships
But prefer masculine ones during ovulation

Question 21

Weakness of infradian

Answer 21

Other factors affect periods
Women living together not taking oral contraceptives have their cycles sync

And there was a study

Question 22

What was the study that disapproves infradian rhythms

Answer 22

Sweat of a group of females rubbed on upper lip of other females
Causing period synchronisation

Question 23

Why did the two groups periods sync due to sweat?

Answer 23

Because of pheromones

Question 24

What are pheromones?

Answer 24

Chemical substance released into environment that affects behaviour of others of same species

Question 25

What are endrogenous pacemakers?

Answer 25

Internal biological rhythms

Question 26

What are exogenous zeitgebers?

Answer 26

External cues or factors

Question 27

What are EP and EZ used for?

Answer 27

Used to reset biological rhythms daily

Question 28

What are suprachiasmatic nuclei?

Answer 28

Tiny cluster of nerve cells in the hypothalamus that act as a master clock to link brain regions and control all of the biological clocks in the body

Question 29

How do you suprachiasmatic nuclei carry out their function?

Answer 29

Synchronise

Targeting neurons in other sites to get time coordinated signals

Question 30

What hormone does the SCN regulate?

And how

Answer 30

Manufacture and secretion of melatonin in the pineal gland via an interconnecting neural pathway

It sends a signal to the gland that increases melatonin at night and it decreases it as light levels increase

Question 31

Evaluation of endogenous pacemakers

Answer 31

+Folkard studied Kate, she spent 25 days in a lab with no access to EZ of light
Parkour temperature rhythm was at 24 hours therefore you don’t need EZ to maintain internal biological rhythms
-Kate sleep wake cycle extended to 30 hours with asleep period of 16 hours therefore we do need EZ

Question 32

What are receptors in the SCN sensitive to?

Answer 32

Lights changes

Used to synchronise the activity of organs and glands and resets the biological clock daily

Question 33

What is melanopsin?

Answer 33

Protein in the retina that sensitive to natural light

Question 34

What does moving to the nightshift or a different time zone resulting?

Answer 34

EP to impose inbuilt rhythms of sleep that is out of sync with EZ of light

-disrupted sleep patterns, increased anxiety, decrease in alertness

Question 35

Strengths of exogenous zeitgebers

Answer 35

+ Blind people with light perception have a normal circadian rhythms but those without have abnormal
+ Burgess, exposure to light prior to East West flights decrease the time needed to adjust to local time

Question 36

Weakness of exogenous zeitgebers

Answer 36

-Arctic regions have normal sleeping pattern is so EZ has little influence on internal biological rhythms