AWAKENESS AND SLEEP

Question 1

…………………………..is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours.

Answer 1

A circadian rhythm or circadian cycle

Question 2

…………………………..is a test used to evaluate the electrical activity in the brain. Brain cells communicate with each other through electrical impulses. An EEG can be used to help detect potential problems associated with this activity

Answer 2

ELECTROENCEPHALOGRAM (EEG)

Question 3

1. Their frequency is about 8 to 13 cycles per second (hertz).
2. are present in the EEG of almost all normal persons and appear when the subject is awake, at rest, and keeps his/her eyes closed.
3. They disappear during sleep (except during REM sleep).

Answer 3

Alpha wave of the encephalon generated by EEG

Question 4

1. They have a frequency of 1 to 5 Hz.
2. They occur when the subject is in a state of deep sleep; they are normal in awake children.
3. They indicate a cerebral lesion when they are produced in an awake adult.

Answer 4

Delta waves

Question 5

1. Their frequency varies from 14 to 30 Hz.

2. They usually appear when the nervous system is in activity, i.e. during periods of mental and sensory activity.

Answer 5

Beta waves

Question 6

1. The frequency of theta waves varies from 4 to 7 Hz.
2. They are produced in children and in adults in the state of emotive stress.
3. They occur during several cerebral diseases.

Answer 6

Theta waves

Question 7

There are two types of normal sleep

Answer 7

1. slow wave sleep

2. paradoxical sleep:
 (I) in paradoxical sleep, EEG shows alpha waves.  (II) It is the Rapid 
      Eye Movement (REM) sleep.  
(III)During the paradoxical sleep, the muscular tonus is very reduced 
      (except for the eye movements). 
 (IV) It is during the paradoxical sleep that most dreams occur.

Question 8

stages of slow wave sleep

Answer 8

Stage 1 ( awakeness and sleep states ): 1-7 minutes. On EEG, alpha waves decrease and theta waves appear

Stage 2 ( first true sleep stage ) the subject sleeps only slightly. EEG shows theta waves.

Stage 3 ( relatively deep sleep ) The subject is very relaxed. EEG indicates delta waves. occurs about 20 minutes after the subject falls asleep.

stage 4 ( Deep sleep appears ) The subject is very relaxed and reacts slowly if he is awakened. EEG is dominantly delta waves.

Question 9

In a period of typical sleep, paradoxical sleep totalizes

Answer 9

90 to 120 min

Question 10

Periods of paradoxical sleep and slow wave sleep alternate all along the night, with approximately ………………..intervals between paradoxical sleep periods.

Answer 10

90 minutes

Question 11

This cycle is repeated ………………..during the whole period of sleep.

Answer 11

three to five times