sleep Flashcards
what is sleep
sleep is a naturally recurring state characterized by altered consciousness, reduced sensory activity, and inhibition of voluntary muscles
why is sleep important
it is a vital physiological process essential for overall health and well-being
what happens during sleep?
the body undergoes various restorative processes, such as memory consolidation, hormone regulation and cellular repair, contributing to physical and cognitive functions.
why do we sleep when we do?
the human sleep-wake cycle is a circadian rhythm. its a natural, internal biological clock that cycles roughly every 24 hours. it is regulated by the suprachiasmatic nucleus in the hindbrain, influences the release of the sleep-inducing hormone melatonin. Melatonin levels typically rise in the evening, promoting sleep, and decrease in the morning to promote wakefulness
melatonin
melatonin is a natural product found in plants and animals. it is primarily known in animals as a hormone released by the pineal gland in the brain at night, and has long been associated with control of the sleep-wake cycle
pineal gland
a gland located in the centre of the brain that helps regulate body rhythms and sleep cycles.
key factors influencing the timing of sleep
- light exposure
- social and environmental cues
- temperature fluctuations
- individual variations.
functions of sleep
restoration and repair, memory consolidation, energy conservation, hormonal regulation and cognitive function.
what happens when we sleep
we become unresponsive to external stimuli, however we are very active during sleep.
processes that the body goes under during sleep
hormonal regulation, immune system support, an metabolic regulation
the two types of sleep
non-rapid eye movement (NREM) sleep
rapid eye movement (REM) sleep
- periods of NREM sleep alternate with REM sleep about 4-5 times during a nights sleep
characteristics and patterns of sleep - REM
- a type of sleep characterised by brainwaves with high frequency and low amplitude
- the muscles of the body are in a state of paralysis and dreams may be experienced
NREM stage 1
light sleep; transition from wakefulness to sleep. it lasts for a few minutes, and its easy to be awakened
alpha, theta 5-10mins
characteristics and patterns of sleep - NREM
- 4 stages
- characterised by relaxation of the muscles, a slowing down of physiological functions and brainwaves that decrease in frequency and increase in amplitude.
NREM stage 2
slightly deeper sleep; characterised by the presence of sleep spindles and K-complexes. body temperature decreases, and heart rate slows
theta 10-20mins
NREM stage 3
Slow-Wave Sleep (SWS)
Deep sleep stages; essential for physical restoration and growth. these stages are often referred to as ‘deep sleep’
theta delta 30 mins
REM sleep dreaming
most vivid dreams occur during REM sleep. brain activity is similar to wakefulness, but voluntary muscles are temporarily paralyzed, preventing the physical enactment of dreams
REM sleep memory consolidation
REM sleep is associated with the consolidation of emotional and procedural memories
REM sleep brain restoration
REM sleep is believed to play a role in maintaining cognitive function and emotional well-being
sleep hygiene
Sleep hygiene refers to a set of practices and habits that promote good sleep quality and overall healthy sleep. These practices aim to create an environment and lifestyle conducive to restful and rejuvenating sleep.
brain waves
beta, alpha, theta, delta
what does EEG measure
Detects, Amplifies, and records the electrical activity of the brain in the form of brainwaves.
beta brain wave
high frequency and low amplitude
- indicates
- awake, active, and alert state (i.e normal waking consciousness)
- REM sleep
alpha brain wave
medium frequency and medium to low amplitude
indicates:
hypnogogic state (awake and relaxed)
daydreaming, meditating
NREM stage 1
theta brain waves
medium frequency and a mixture of high to medium amplitude
- indicates:
NREM stage 1, NREM stage 2, NREM stage 3 (only first half)
delta brainwaves
low frequency and high amplitude
indicates:
NREM stage 3 (later half)
NREM stage 4 (deep sleep)
brainwaves from light sleep to deep sleep
- beta - awake 2. alpha - relaxed 3. theta - asleep 4. delta - deep sleep
4 NREM
deepest, hard to wake, disorientated (delta) 20 mins at beginning less as night goes on
sleep deprivation
if we don’t get enough sleep then we experience sleep deprivation
consequences include low concentration and attention
if we are sleep deprives than we may experience microsleeps - brief periods where we drift into sleep but still appear awake.
REM sleep deprivation
daytime memory lapses, poor concentration and anxiety
experienced more REM sleep than they usually would experience REM rebound
REM rebound
the recovery (‘catching up’) of REM sleep immediately following a period of lost REM sleep by spending more time than usual in REM sleep
that is, increasing the relative amount of REM sleep during subsequent sleep periods
psychological effects of sleep deprivation
Simple and routine tasks are very difficult for the sleep deprived-most people experience problems with attention and concentration eg driving a car
physical effects of sleep deprivation
may cause physical growth processes to be interrupted.
muscle strength and endurance is reduced
Ability to form fine motor functions such as hand writing is impaired
Immune system is weakened
increased chance of infections
Appetite increases and this can lead to long term weight gain
microsleeps
A very short period (2–5 second) of drowsiness or sleep that occurs while a person is apparently awake
how much sleep do we need
- Over the course of our lifespan, the amount of sleep we need changes.
- Amount of night-time sleep decreases with age
- Proportion of time spent in REM decreases with age
what are dreams
Every night we experience strange narratives and stories when we sleep.
These are dreams, and most often occur during the stage of REM (rapid eye movement) sleep.
freuds psychodynamic theory of dreaming
Sigmund Freud theory was the psychoanalytic that we dream to safely release troubling and anxiety producing thoughts.
the threat simulation theory of dreaming
Antti Revonsuo’s evolutionary hypothesis suggests that dreaming, especially intense and threatening scenarios during REM sleep, evolved as a survival mechanism, allowing the brain to simulate and rehearse responses to potential dangers.
polysomnograpphy
a test used to diagnose sleep disorders.
evolutionary psych
Evolutionary psychology is a branch of psychology that studies human behavior, thought, and feeling through the lens of evolutionary biology.
