Ch.14.3 Human Sleep Exhibits Different Stages

Question 1

What is the ‘free-run’ sleep-wake circadian rhythm of humans?

Answer 1

25 hours - found when people were in a cave without external cues (light, meal, jobs, alarm clocks).

Question 2

What is an electroencephalography (EEG)

Answer 2

The recording and study of gross electrical activity of the brain recorded from large electrodes placed on the scalp.

Question 3

What is an electrooculography?

Answer 3

The electrical recording of eye movements.

Question 4

What is an electromyography?

Answer 4

The electrical recording of muscle activity.

Question 5

What are the two distinct classes of sleep?

Answer 5

1. Rapid-eye-movement sleep (REM sleep)
2. Non-REM sleep (NREM)

Question 6

What is Rapid-eye-movement sleep (REM sleep)?

Answer 6

Also called paradoxical sleep. A stage of sleep characterized by small-amplitude, fast-EEG waves, no postural tension, and rapid eye movements.

Question 7

What is non-REM (NREM) sleep?

Answer 7

Sleep without rapid eye movements. In humans this is divided into stages (1, 2, and 3 sleep)

Question 8

What is beta activity? (also called desynchronized EEG)

Answer 8

EEG activity seen in wakefulness, comprising a mix of many different high frequencies with low amplitude. AWAKE

Question 9

What is stage 1 of NREM sleep?

Answer 9

Alpha

Question 10

What are vertex spikes?

Answer 10

A sharp-wave EEG pattern that is seen during stage 1 sleep.

Question 11

What is seen in stage 1 NREM sleep? (also called NREM 1)

Answer 11

1. Alpha rhythms
2. vertex spikes
3. slowing of heart rate
4. a reduction of muscle tension
5. eyes may roll about slowly under closed eyelids
6. Lasts several minutes.

Question 12

What are sleep spindles?

Answer 12

A characteristic 12-14 Hz wave in the EEG of a person in stage 2 sleep. Occur in periodic bursts.

Question 13

What are K complexes?

Answer 13

A sharp negative EEG potential that is seen in stage 2 sleep.

Question 14

What is seen in stage 2 NREM sleep? (also called NREM 2)

Answer 14

1. Sleep spindles
2. K complexes

Question 15

An interesting fact about those awaken in stage 1 or 2 of sleep.

Answer 15

Many will deny that they were asleep

Question 16

What is stage 3 sleep (NREM 3)?
Also called slow-wave sleep (SWS)

Answer 16

A stage of sleep that is defined by the presence of large-amplitude, very slow waves (delta waves)

Question 17

What are delta waves?

Answer 17

The slowest type if EEG wave, about 1 Hz, characteristic of stage 3 sleep.

Question 18

How long do the 3 stages of NREM last?

Answer 18

About 90 mins - the time usually required for progression through these stages, with a brief return to stage 2.

Question 19

What is the condition atonia?

Answer 19

A pattern of small-amplitude, high-frequency activity similar in many ways to the pattern of an awake individual, but the skeletal muscles are completely relaxed and limp. This is typical of REM sleep.

Question 20

Which cat is in REM?

Answer 20

B - The kitten in A is enjoying slow-wave sleep, with enough muscle tone to maintain a sphinxlike posture. The kitten in B has profoundly relaxed muscle tone (atonia)

Question 21

Why in REM sleep are the muscles in a flaccid state (relaxed) despite the intense brain activity?

Answer 21

Because the brainstem regions are profoundly inhibiting motor neurons.

Question 22

What happens in REM sleep?

Answer 22

Question 23

What happens in NREM sleep?

Answer 23

Question 24

What does a typical night of adult sleep look like? - Not sure you need to know this

Answer 24

A. 4 to 5 repeating cycles about 90-110 minutes long.
B. Cycles early in the night are characterized by greater amounts of stage 3 SWS
C. The latter half of the night has less stage 3 sleep and more REM sleep than the first half of the night.
D. The first REM period is the shortest, while the last REM period, just before waking, may last up to 40 minutes.
E. A brief arousal occasionally occurs immediately after a REM period - a sleeper may shift posture at this time.