Sleep and Waking

Question 1

What behaviours occur in response to internal biological clocks?

Answer 1

• Seasonal migration.
• Mating seasons.
• Human menstrual cycle.

Question 2

What is circadian rhythm?

Answer 2

A natural 24-hour cycle.

Question 3

What is a free running circadian rhythm?

Answer 3

A 22-25 hour circadian rhythm cycle in the absence of natural light.

This is seen in those who are blind, or those on submarines.

Question 4

What is the location of the body’s internal ‘master’ clock?

Answer 4

The Suprachiasmatic nucleus, located in the hypothalamus.

Question 5

Where is the suprachiasmatic nucleus located?

Answer 5

In the hypothalamus, located above the optic chiasm.

Question 6

What evidence implicates the SCN as the master internal clock?

Answer 6

Radioactive 2-deoxyglucose (2-DG) has been used to identify SCN activity.

Question 7

What are the two chemical messengers released by the retinohypothalamic tract onto neurons in the SCN?

Answer 7

• Glutamate.
• PACAP.

Question 8

When is glutamate released?

Answer 8

Glutamate is released in response to light, signalling the SCN that daylight has begun.

Question 9

What is the role of PACAP?

Answer 9

It is thought to modulate the action of glutamate on the SCN - allowing for the response of different levels of light.

Question 10

What does the SCN regulate and respond to?

Answer 10

The SCN regulates and responds to the hormone melatonin, secreted by the pineal gland.

Question 11

Where is melatonin produced?

Answer 11

In the retina.

Question 12

What is shift maladaptive syndrome?

Answer 12

40-80% of those working night shifts will experience disturbed sleep.

Question 13

What is jet lag?

Answer 13

The interaction of internal and external clocks.

Question 14

How many hours of sleep do 65+ year olds need?

Answer 14

7-8 hours.

Question 15

How many hours of sleep do 26-64 year olds need?

Answer 15

7-9 hours

Question 16

How many hours of sleep do 18-25 year olds need?

Answer 16

7-9 hours

Question 17

How many hours of sleep do 14-17 year olds need?

Answer 17

8-10 hours

Question 18

How many hours of sleep do 6-13 year olds need?

Answer 18

9-11 hours

Question 19

How many hours of sleep do 3-5 year olds need?

Answer 19

10-13 hours

Question 20

How many hours of sleep do 1-2 year olds need?

Answer 20

11-14 hours

Question 21

How many hours of sleep do 4-11 month olds need?

Answer 21

12-15 hours

Question 22

How many hours of sleep do 0-3 month olds need?

Answer 22

14-17 hours

Question 23

Describe stage 1 of sleep.

Answer 23

• Light sleep.
• Muscle activity slows down.
• Occasional muscle twitching.

Question 24

Describe stage 2 of sleep.

Answer 24

• Breathing pattern slows.
• Heart rate slows.
• Slight decrease in body temperature.

Question 25

Describe stage 3 of sleep.

Answer 25

- Deep sleep begins. - Brain begins to generate slow delta waves.

Question 26

Describe stage 4 of sleep.

Answer 26

- Very deep sleep. - Rhythmic breathing. - Limited muscle activity. - Brain produces delta waves.

Question 27

Describe stage 5 of sleep.

Answer 27

- Rapid eye movement (REM sleep). - Brainwaves speed up. - Dreaming occurs. - Muscles relax. - Heart rate increases. - Breathing is rapid and shallow.

Question 28

What is used to measure brain activity during sleep?

Answer 28

Electroencephalogram (EEG)

Question 29

What occurs during REM sleep?

Answer 29

- Increase in heart rate. - Increase in blood pressure. - Breathing becomes rapid and irregular. - Increased blood flow to genital organs. - Other major muscle groups are effectively paralysed. - The sleeper may jerk or twitch.

Question 30

When does dreaming occur?

Answer 30

During REM sleep and SWS.

Question 31

Describe REM dreams.

Answer 31

REM dreams are lengthy, complicated, vivid and story like.

Question 32

Describe SWS dreams.

Answer 32

SWS dreams are short episodes characterised by logical single images and a relative lack of emotion.

Question 33

What do dreams of being unable to move in a dangerous situation mirror?

Answer 33

They mirror the muscle paralysis presented during the REM state.

Question 34

What are lucid dreams?

Answer 34

Where the dreamer becomes aware of the fact they are dreaming, and are able to direct the dreams content.

Question 35

What brain region is responsible for slow wave sleep (SWS)?

Answer 35

The forebrain.

Question 36

What brain area appears to encourage sleep by inhibiting the arousal normally produced by the reticular formation?

Answer 36

The raphe nuclei (located in the brainstem).

Question 37

What is the activity of the reticular formation associated with?

Answer 37

Wakefulness.

Question 38

What is the Ascending Reticular Activating System (ARAS)?

Answer 38

A network of neural fibres fundamental to the regulation of arousal.

Question 39

What role does acetylcholine play in sleep?

Answer 39

- Increases arousal. - Increases REM sleep.

Question 40

What role does noradrenalin play in sleep?

Answer 40

Increases arousal.

Question 41

What role does serotonin play in sleep?

Answer 41

- Increases sleep time. - Decreases REM.

Question 42

What are two types of sleep disorders?

Answer 42

- Dyssomnias. - Parasomnias.

Question 43

What does dyssomnia involve?

Answer 43

Difficulties in the initiation, maintenance, timing and quality of sleep.

Question 44

When does parasomnia occur?

Answer 44

When unusual behaviours disturb ongoing sleep.

Question 45

What are some sleep disorders?

Answer 45

- Idiopathic Hypersomnia. - Narcolepsy. - Sleep Apnea. - Sleep state misperception. - Fatal familial insomnia.

Question 46

What is Narcolepsy?

Answer 46

A chronic neurological disorder caused by autoimmune destruction of hypocretin-producing neurons.

Question 47

What is Sleep Apnea?

Answer 47

Characterised by pauses in breathing or instances of shallow or infrequent breathing during sleep.

Question 48

What is SIDS?

Answer 48

When a healthy baby, usually between the ages of 2-4 months dies while asleep.