Which of the following conditions characterizes rapid eye movement (REM) sleep?
A. Disorientation and disorganized thinking.
B. Jerky limb movements and position changes.
C. Pulse rate slowed by 5 to 10 beats/minute.
D. Highly active brain and physiological activity levels.
Correct Answer: D. Highly active brain and physiological activity levels.
Highly active brain and physiological activity levels characterize REM stage. The amount of REM in each cycle progresses throughout the night from being minimal on the initiation of sleep but eventually is up to 30% of the cycle later in the night.
Option A: Stages 3 and 4 of NREM sleep are characterized by disorientation and disorganization. NREM stage 3 lasts about 20 to 40 minutes, initially. EEG is characterized by high-voltage, slow-wave frequency.
Option B: During REM sleep, the body movement ceases except for the eyes. REM is the phase of sleep responsible for dreaming. It is characterized by total body voluntary muscle paralysis (except for the extraocular muscles). This paralysis is thought to be a mechanism to prevent neural stimulus from dreams to manifest in actual muscular impulses during sleep.
Option C: The pulse rate slows by 5-10 beats/minute during NREM sleep, not REM sleep. Sleep begins with a short NREM stage 1 phase, followed by NREM stage 2, then NREM stage 3, then finally into REM. NREM accounts for approximately 75% to 80% of total sleep, and REM accounts for the remaining 20% to 25% of sleep.
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