Phsiology Of Sleep

Question 1

What are the 3 functions of sleep?

Answer 1

1) restoration
2) energy conservation (sleep to save calories)
3) brain processing and memories (Brian functioning)

Question 2

What are the consequences of sleep deprivation?

Answer 2

1) poor memory
2) poor judgement
3) poor creativity
4) poor responsiveness

Question 3

What is the structure of sleep?

Answer 3

Works on a 24-25 hour cycle

Question 4

What are the 2 stages of sleep?

Answer 4

1) REM sleep (rapid eye movement) - associated with dreaming, skeletal muscles are paralysed
2) Non-REM (non rapid eye movement) - includes 4 stages

Question 5

How can brain activity be measured?

Answer 5

Electroencephalogram (EEG)

Question 6

Describe NREM…

Answer 6

Most of our sleep

Characterised by reduction in physiological activity

Sleep gets deeper- brain waves get slower and have greater amplitude

Breathing and HR slow down

Question 7

Describe REM…

Answer 7

Occurs in 80-100 minutes after onset of sleep

Occurs every 90 mins

Each period lasts about 5-30 mins

REM and HR/BR irregular

Associated with dreaming (remembered if woken)

Approx. 4-5 cycles per night

Question 8

What is a circadian rhythm?

Answer 8

Bodily changes that follow a 24- hour cycle

Fluctuations in our bodies where hormone secretion, body temp. and other physiological factors vary on cyclical basis- set to certain external factors or internal factors

Changes occur in 24 hour period- regular increases and decreases of cellular activities

Question 9

What is the pineal gland?

Answer 9

‘Third eye’

Indirectly responds to light

Question 10

What is the suprachiasmatic nucleus (SCN)?

Answer 10

Biological clock and influences the pineal gland

Works with pineal gland to orchestrate the secretion of the hormone melatonin

Question 11

What is melatonin?

Answer 11

The hormone of sleep

Increases feeling of sleepiness and secreted at night

Question 12

What affect does light and darkness have on melatonin?

Answer 12

Darkness- stimulates the release

Light- inhibits the release

Question 13

How is melatonin made?

Answer 13

Made from serotonin

Made form essential amino acid Tryptophan

Question 14

What is tryptophan?

Answer 14

Rich in certain foods eg milk, chocolate, seeds and nuts

Question 15

What is the function of serotonin?

Answer 15

Associated with the feeling of wellbeing and relaxation

Secreted in response to light

Question 16

What is the sequence of events involved in sleep wake cycle

Answer 16

1) light falls on retina
2) nerve pathways to SCN
3) nerve fibres to pineal gland
4) noradrenaline secreted at synapses
5) inhibition of pineal gland
6) melatonin secretion suppressed