8.9 Understanding Sleep

These flashcards cover key terms related to sleep waves and stages, including their definitions.

alpha wave

A type of relatively low frequency, high amplitude brain wave that becomes synchronized; characteristic of the beginning of stage one sleep.

delta wave

A type of low frequency, high amplitude brain wave characteristic of stage three sleep.

non-REM (NREM) sleep

A period of sleep outside periods of REM sleep.

rapid eye movement (REM) sleep

A period of sleep characterized by brain waves very similar to those during wakefulness and by darting movements of the eyes under closed eyelids.

stage one sleep

The first stage of sleep; a transitional phase that occurs between wakefulness and sleep.

stage two sleep

The second stage of sleep; the body goes into deep relaxation; characterized by the appearance of sleep spindles.

stage three sleep

The third stage of sleep; deep sleep characterized by low frequency, high amplitude delta waves.

sleep rebound

Sleep-deprived individuals will experience longer sleep latencies during subsequent opportunities for sleep.