Sleep stage 3 is distinguished from sleep stage 4 by the: a. ...

[lindiwe]

Sleep stage 3 is distinguished from sleep stage 4 by the:
 
  a. Presence of bursts of theta waves
  b. Presence of sleep spindles and k-complexes
  c. Percentage of large delta waves present on the electroencephalogra m
  d. Percentage of relatively low-voltage, mixed-frequency waves

Question 2

What is the distinguishing feature of the electroencephalogra m during sleep stages 3 and 4?
 
  a. Small beta waves c. Sleep spindles
  b. Large k-complexes d. Large delta waves

[kbennett34]

Answer to Question 1

ANS: C
The distinction between stage 3 and stage 4 is usually found in the presence of large delta waves, or slow waves. At the beginning of stage 3, delta waves constitute 20 to 50 of the electroen-cephalogram. Stage 4 is identified by the presence of the delta waves for at least 50 of the electroencephalogra m recording.

Answer to Question 2

ANS: D
The deepest stages of non-REM sleep (stages 3 and 4) are referred to as slow-wave sleep because of the presence of large delta waves that appear when the sleeper enters these stages.