Sleep and Dreams Flashcards
What is sleep?
Periodic, natural loss of consciousness- as distinct from unconsciousness resulting from a coma, general anaesthesia or hibernation
Describe a circadian rhythm
- Biological Clock
- Regular bodily rhythms (of temperature and wakefulness) on 24 hour cycle
- Thinking and memory peaks
- Sleep cycle repeats every 90 minutes
What is REM sleep?
- Rapid eye movement sleep
- Recurring sleep stage during which vivid dreams commonly occur
- Known as “Paradoxial Sleep”, because muscles are relaxed but other body systems are active
- Periods of fast, jerky eye movements were accompanied by energetic brain activity (motor cortex is active)
What are alpha waves in sleep?
Relatively slow brain waves of a relaxed, awake state
Describe stage 1 Non-REM sleep
- Experience fantastic images resembling hallucinations: sensory experiences that occur without sensory stimulus
- May have sensation of falling or float weightlessly
- Hypnagogic sensations later incorporated into your memories
What are hallucinations?
False sensory experiences, such as experiencing something in absence of external visual stimulus
Describe stage 2 Non-REM sleep
- Periodic sleep spindles: bursts of rapid, rhythmic brain wave activity
- Awakened without too much difficulty
Describe stage 3 Non-REM sleep
- During this slow wave sleep, which lasts for about 30 minutes
- Brain emit large, slow delta waves and you are hard to awaken
What are delta waves in sleep?
The large, slow brain waves associated with deep sleep
What affects our sleep patterns?
- Bright light tweaks circadian clock by activating light-sensitive retinal problems
- Proteins control circadian clock by triggering signals to SCN (cell clusters in hypothalamus)
- Causes brain’s pineal gland to decrease its production of sleep inducing hormone melatonin
What is Suprachiasmatic Nucleus (SCN)?
- A pair of cell clusters in the hypothalamus that controls circadian rhythm
- In response to light, the SCN causes pineal gland to adjust melatonin production
- Modifying feelings of sleepiness
Describe the body’s biological clock
- Light striking the retina signals the SCN to suppress the pineal gland’s production of sleep hormone melatonin
- At night, SCN quiets down, allowing pineal gland release melatonin into bloodstream
What are the main reasons why we sleep?
1) Sleep protects
2) Sleep helps us recuperate
3) Sleep helps restore and rebuild our fading memories of the day’s experiences
4) Sleep feeds creative thinking
5) Sleep supports growth
What are the major effects of sleep loss?
- Difficulty studying, diminished productivity, tendency to make mistakes, irritability, fatigue
- Weight gain: increases ghrelin (hunger-arousing hormone) and decreases leptin (hunger-suppressing), decreases metabolic rate, -Increases cortisol (stress hormone)
- Suppress immune cells that battle viral infections
- Less sleep= more accidents
What are examples of major sleep disorders?
- Insomnia
- Narcolepsy
- Sleep Apnea
- Night Terrors
- Sleepwalking/sleep talking
