Sleep

Question 1

What prevents the acting out of dreams within REM sleep?

Answer 1

Inhibition of all skeletal muscles except the eyes, due to inhibitory projections from the pons to the spinal cord.

Question 2

What is REM Sleep Behavioural disorder?

Answer 2

The lack of inhibitory projections from the pons to the spinal cord so skeletal muscles of the body aren’t inhibited during sleep. Individuals act out their dreams.

Question 3

What is REM sleep dependent on?

Answer 3

Cholinergic pathways within the reticular formation and their projections into the thalamus, hypothalamus and cortex.

Question 4

What happens when we are deprived of REM sleep?

Answer 4

There is a catch up when we next sleep indicating that is very important for physiological function.

Question 5

What do sleep deprived subjects demonstrate?

Answer 5

Impairment of cognitive function.
Impairment of physical performance.
Sluggishness.
Irritability. 
Some also experience Psychosis.

Question 6

What does Sleep support?

Answer 6

Neuronal plasticity
Learning and memory
Cognition
Clearance of waste products from the CNS.
Conservation of whole body energy. 
Immune function.

Question 7

What is somnambulism?

Answer 7

Sleep walking. Occurs in non REM sleep and is more common in children. They can walk with their eyes operand carry out tasks but have no recall when woken.

Question 8

What is narcolepsy?

Answer 8

The sudden onset of REM sleep with no warning. Very dangerous as it poses a high accident risk.

Question 9

Where does the circadian rhythm originate?

Answer 9

It is located in the suprachiasmatic nucleus of the hypothalamus. Its neutrons have a 24 hr inherent cycle that is entrained by external cues.

Question 10

What is sleep?

Answer 10

Level of unconsciousness from which an individual can be aroused by normal stimuli. It is a cyclical process.

Question 11

What is thought to be associated with controlling consciousness?

Answer 11

Reticular Formation

Question 12

What is the role of serotonin in sleep?

Answer 12

Believed to be involved in sleep induction and is a precursor for melatonin which increases every night as we sleep and decreases as we near waking.

Question 13

What is orexin required for?

Answer 13

Wakeness.

Question 14

What is an EEG?

Answer 14

Electroencephalogram - records the activity of neurons.

Question 15

What happens to frequency of waves when neuronal excitation increases?

Answer 15

Generally frequency of waves also increases.

Question 16

What are the properties of alpha waves?

Answer 16

High frequency.
High amplitude.
Relaxed awake state.

Question 17

What are the properties of beta waves?

Answer 17

Higher frequency than alpha.
Low amplitude.
Alert, awake state.

Question 18

What are the properties of theta waves?

Answer 18

Low frequency.
Varied amplitude.
Emotional stress/frustration and sleep.

Question 19

What are the properties of delta waves?

Answer 19

Low frequency.
High amplitude.
Deep sleep.

Question 20

What is the first stage of the sleep cycle?

Answer 20

Slow wave, Non-REM sleep. Involves slow eye movements and people are easily aroused.
Theta waves.

Question 21

What is the second stage of the sleep cycle?

Answer 21

Frequency of wave slows down. Sleep spindles occur which are bursts of rapid waves. Eye movements stop.

Question 22

What is the third stage of the sleep cycle?

Answer 22

High amplitude
Delta waves
Spindle activity decreases.
Beginning of deep sleep.

Question 23

What is the fourth stage of sleep.

Answer 23

Delta waves.

Deep sleep.

Question 24

What is REM sleep?

Answer 24

Rapid eye movement sleep. EEG recording appears similar to alert awake waves. Dreams occur in this stage and it normally lasts 5-30mins every 90mins, increasing as the night goes on.