| A | B |
|---|
| Consciousness | The state or quality of awareness of the self and the environment |
| Circadian Rhythm | Biological clock that regulates bodily rhythms on a 24-hour cycle |
| Sleep Cycle | Lasts about 90 minutes. Contains 4 sleep stages. |
| Hypnic Jerk | Involuntary twitches or the feeling of falling. |
| REM stage | Characterized by rapid eye movements. Dreaming occurs. |
| Narcolepsy | Periodic and overwhelming sleepiness where people fall asleep while talking or standing up |
| Sleep Apnea | Failure to breathe when asleep |
| Sleep psychologist | Psychologist who studies sleep and treats sleep disorders |
| Insomnia | Trouble falling asleep, staying asleep, or getting good quality sleep |
| Immunity | A person's resistance to (or protection from) a disease |
| Melatonin | a hormone that acts to induce sleep |
| Restorative Theory | States that the function of sleep is to restore the mind and body |
| Alpha waves | Brain wave pattern associated with deep relaxation |
| Beta waves | The brain wave pattern associated with normal mental activity |
| NREM-1 | Light sleep. People who are awakenned during this period may report that they were not yet asleep. |
| NREM-2 | Sleep spindles. Body temperature drops, heart rate slows, breathing becomes shallow and irregular |
| NREM-3 | Deepest stage of sleep. |
| REM rebound | The increased amount of REM sleep that occurs after REM deprivation |
| Inactivity Theory | Suggests that inactivity at night is an adaptation that served a survival function by keeping us out of harm's way at a time when we would be particularly vulnerable |
| Energy Conservation Theory | Suggests the function of sleep is to reduce an individual's energy expenditure at times when it is least efficient to search for food |
| Brain Plasticity Theory | Suggests that sleep plays a critical role in brain development |
