CHAPTER 9: Sleep, Dreaming and Circadian Rhythms

These flashcards cover key vocabulary related to sleep, dreaming, and circadian rhythms, as discussed in Chapter 9.

Circadian Rhythms

A consistent cycle of body activity and behavior that occurs over approximately twenty-four hours.

zeitgeber

External cues that help synchronize circadian rhythms, such as time and temperature.

free-running clock

A circadian rhythm that occurs without external cues and is not always exactly 24 hours.

suprachiasmatic nuclei (SCN)

An area in the hypothalamus that helps regulate circadian rhythms by responding to light information from the retina.

melatonin

A hormone released by the pineal gland that affects sleep and helps reduce jet lag.

polysomnography

A method used to study sleep and sleep disorders that measures various physiological parameters such as heart rate, breathing, and brain waves.

REM sleep

Rapid Eye Movement sleep, associated with dreaming and increased brain activity.

NREM sleep

Non-Rapid Eye Movement sleep, which includes light sleep (Stage 1), moderate sleep (Stage 2), and deep sleep (Stage 3).

theta waves

EEG activity of 3-8 Hz that occurs during early stages of slow-wave sleep.

delta waves

EEG activity of 0.2-3 Hz, associated with the deepest stages of slow-wave sleep.

insomnia

A sleeping disorder characterized by difficulty falling and staying asleep.

sleep apnea

A sleep disorder where breathing is interrupted during sleep, leading to poor sleep quality.

narcolepsy

A disorder characterized by excessive daytime sleepiness, sometimes associated with cataplexy.

caffeine

A common stimulant that inhibits sleep by acting as a competitive antagonist for adenosine.

activation-synthesis hypothesis

A theory suggesting that dreaming is a way for the cortex to make sense of random brain activity during sleep.

glymphatic system

A system in the brain responsible for waste removal, active during sleep.

cataplexy

A condition where muscle atonia associated with REM sleep occurs while the person is awake.

hypnotics

Drugs used to induce sleep; can include benzodiazepines and Z-drugs.

sleep hygiene

Practices that promote consistent sleep patterns and improve sleep quality.

crepuscular

Being active during dawn and dusk and sleeping during the day and night.