Sleep Flashcards
Define sleep.
- Sleep is a regular, naturally occurring altered state of consciousness
- It involves a loss of awareness
- Includes disengagement from both internal and external stimuli
What are brainwaves
Brain waves tell
us how much
activity there is in
the brain.
When we are looking at different brain waves we
looks at two things.
Frequency: this refers to the number of brain
waves per second.
Amplitude: This refers to the size of the
peaks and the troughs
Diferent types of wave lengths
Beta waves: the highest frequency and a lowest amplitude. Beta waves are the ones
registered on an EEG when the subject is awake, alert, and actively processing
information.
Alpha waves: second highest frequency and an second lowest amplitude. Alpha waves
are typically found in people who are awake but have their eyes closed and are relaxing
or meditating.
Theta waves: Theta waves are associated with memory and emotions.
Delta waves: Delta waves are observed when individuals are in deep sleep or in a
coma.
What is NREM sleep
NREM (non-rapid eye movement)
sleep is a type of sleep characterised
by a lack of rapid eye movement and is
subdivided into 3 different stages.
Stages of NREM sleep stage 1
Transition: Moves from being awake to light sleep.
Hypnagogic State: May experience sensations like floating, falling, or a hypnic jerk (sudden muscle twitch).
Awareness: Loses self-awareness and awareness of surroundings but can still hear faint sounds.
Brainwaves: Beta and alpha waves present.
Duration: Lasts approximately 5-10 minutes.
Stages of NREM sleep stage 2:
In stage 2 of NREM sleep, the sleeper is still in a relatively light sleep.
Individuals spend the majority of their time asleep in NREM stage 2.
Alpha/ theta waves. Duration: 10-25 minutes.
Stage 3 NREM sleep
In stage 3 of NREM sleep, the sleeper is in a deep stage of sleep.
It is difficult to wake the sleeper in this stage of NREM.
If the sleeper is woken during this stage they are likely to feel drowsy and
disoriented.
During this stage, sleepwalking and sleep talking are most likely to occur.
Theta/ delta waves. Duration: 20-40 minutes
NREM sleep : brainwaves,
Stage 1: Alpha waves transition to theta waves (light sleep).
Stage 2: Predominantly theta waves with sleep spindles and K-complexes.
Stage 3: Delta waves (deep sleep, slow and high amplitude).
These waves indicate the depth of sleep and relaxation.
NREM sleep : length of time
Stage 1: Light sleep, lasting a few minutes.
Stage 2: Deeper sleep, lasting about 20 minutes per cycle.
Stage 3: Deep sleep (also known as slow-wave sleep), lasting 20-40 minutes in the first sleep cycle and decreasing in duration with subsequent cycles.
Overall, a typical adult may spend about 4-6 hours in NREM sleep during an 8-hour sleep period.
NREM sleep : other characteristics.
The sleeper is considered to have a less active brain than NWC
- Muscle movement is possible for the sleeper during NREM sleep.
- Movement tends to decrease as NREM stages progress.
- Dreams can occur in NREM sleep but they are often non-vivid (as opposed to
REM sleep). - The sleeper does not frequently recall dreams when woken during NREM
sleep.
NREM sleep makes up approximately 75–80%
of a sleep episode.
- NREM sleep tends to become shorter with each
sleep cycle.
REM sleep.
- Stage where dreaming occurs.
- Characterized by rapid eye movements.
- Brain is very active.
- Breathing is irregular, and muscles are relaxed.
- Important for memory consolidation and emotional processing.
- More the brain recovering
REM sleep stages
ycle Timing:
REM sleep starts about 90 minutes after falling asleep.
It occurs approximately every 90 minutes throughout the night.
Cycle Duration:
The first REM period lasts about 10-20 minutes.
Subsequent REM periods become progressively longer, lasting up to 30 minutes or more.
Total REM Sleep:
Over a typical night, a person can experience about 4 to 6 REM cycles, resulting in total REM sleep of about 1.5 to 2.5 hours.
REM sleep: brainwaves
Beta Waves: High-frequency, low-amplitude brainwaves (15-30 Hz), similar to those observed during active thinking and alertness.
Theta Waves: Lower frequency brainwaves (4-8 Hz), which are also present in light sleep and are associated with creativity and relaxation.
REM sleep : length of time
Occurrence:
Begins about 90 minutes after falling asleep.
Repeats several times throughout the night.
Cycle Duration:
Each REM period lasts about 10 to 30 minutes, with longer durations in later cycles.
REM sleep: Other characteristics
Rapid Eye Movements: Eyes move quickly under the eyelids.
Brain Activity: High brain activity, similar to being awake.
Dreaming: Most vivid dreams occur during this stage.
Physiological Changes: Irregular heart rate and breathing.
Muscle Atonia: Most muscles are temporarily paralyzed, preventing acting out dreams.
