chapter 4 state of consciousness

Consciousness

Awareness of internal and external stimuli

Homeostasis

Tendency to maintain a balance, or optimal level, within a biological system

Circadian rhythm

Biological rhythm that occurs over approximately 24 hours

Suprachiasmatic nucleus (SCN)

Area of the hypothalamus in which the body’s biological clock is located

Stage 1 sleep

First stage of sleep; transitional phase that occurs between wakefulness and sleep; the period during which a person drifts off to sleep

Stage 2 sleep

Second stage of sleep; the body goes into deep relaxation; characterized by the appearance of sleep spindles

Stage 3 sleep

Third stage of sleep; deep sleep characterized by low frequency, high amplitude delta waves

REM sleep behavior disorder (RBD)

Sleep disorder in which the muscle paralysis associated with the REM sleep phase does not occur; sleepers have high levels of physical activity during REM sleep, especially during disturbing dreams

Parasomnia

One of a group of sleep disorders characterized by unwanted, disruptive motor activity and/or experiences during sleep

Sleep apnea

Sleep disorder defined by episodes during which breathing stops during sleep