Nervous System Physiology Part 12 Flashcards
What are the two phases of sleep?
NREM (non-rapid eye movement) and REM (rapid eye movement).
How is NREM sleep divided?
Into three stages: N1, N2, and N3.
What characterizes the three stages of NREM?
Each successive stage is characterized by an EEG pattern with a lower frequency and larger amplitude than the preceding one.
What happens in stage N1 sleep?
theta waves begin to be interspersed among the alpha pattern.
What happens in stage N2?
high-frequency bursts called sleep spindles and large-amplitude K complexes occasionally interrupt the theta rhythm
What happens in stage N3 sleep?
delta waves first appear along with the theta rhythm; as this stage continues, the dominant pattern becomes a delta rhythm N3, sometimes referred to as slow-wave sleep.
What is REM sleep also known as ? And why?
paradoxical sleep
because even though a person is asleep and difficult to arouse, his or her EEG pattern shows intense activity that is similar to that observed in the alert or awake state.
How do the stages of sleep progress in a typical cycle? If uninterrupted
From NREM Stage N1 → N2 → N3 → back to N2 → then to an episode of REM sleep.
How long is one typical sleep cycle?
About 90 to 100 minutes.
How many sleep cycles does the average adult go through per night?
4 or 5
How does brain oxygen consumption during REM sleep compare to NREM or waking states?
higher during REM sleep than during the NREM or awake states.
What do people often report when awakened during REM sleep?
they have been dreaming.
