physio psych Sleep quiz finals

behavioral description of sleep

naturally recurring state characterized by reduced consciousness, decreased sensory responsive to external stimuli, and distinctive patterns of brain activity.

physiological description of sleep

reversible state distinct from wakefulness, marked by changes in physiological functions such as heart rate, breathing, and brain waves.

2 stages of sleep

non-rapid eye movement (NREM) sleep

rapid eye movement (REM) sleep

2 basic patterns of brain activity

beta activity

alpha activity

beta waves

15-30 Hz

awake, normal alert consciousness

alpha waves

9-14 Hz

relaxed, calm and light meditation

frequency of beta activity

from 12 to 30 cycles per second — beta waves have a relatively high frequency.

amplitude of beta activity

ranging from 15 to 30 microvolts — have lower amplitude compared to alpha waves.

neocortex, particularly in the frontal and parietal regions of brain

beta activity is often observed where?

associated mental state of beta activity

is associated with wakeful, alert, and active mental states. It is prominent during tasks requiring focused attention, concentration, and cognitive processing.

beta wctivity is often present when

individuals are engaged in problem solving,bdecision making, or activities requiring motor coordination and movement.

frequency of alpha waves

ranging from 8 to 12 hz — relatively lower frequency compared to beta waves

amplitude of alpha waves

ranging from 20 to 200 μV — have higher amplitude compared to beta waves

location of alpha activity

commonly observed in the occipital region of the brain, butbit can also be present in other areas.

associated mental state of alpha activity

associated with a relaxed but wakeful state. It is often observed when individuals are awake but mentally idle, such as during relaxation or passive observation.

stage 1 of NREM sleep

transition between sleep and wakefulness

brain wave patterns transition from alpha waves (awake) to theta waves (transitional sleep)

stage 2 NREM sleep

10 mins after stage 1 NREM sleep

Contains periods of Theta waves, sleep spindles, and K complexes

sleep spindles

brief bursts of brain activity during stage 2 of NREM sleep. with a frquency of around 12-14 hertz.

sleep spindles are believed to be

play a role in the consolidation of memory and in regulating the transition between different stages of sleep.

k complexes

another type of characteristic brain wave pattern during sleep. it's function is not fully understood but they are believed tonserve as a protective mechanism for sleep.

stage 3 of NREM sleep

deepest stage of NREM sleep

characterized by the presence of slow brain waves called delta waves

particularly importantbfor physical restoration and repairas growth hormone is often released during this stage, contributing to tissue repair and growth.

stage 3 NREM memory consolidation

helping to solidify memories and information

acquired during waking hours.

duration of stage 3 NREM

The duration of Stage N3 sleep varies throughout the night. It tends to be longest in the first sleep cycle and decreases in subsequent cycles. During the first sleep cycle, Stage N3 may last around 20 to 40 minutes, but its duration typically decreases as the night progresses

percentage of total sleep time (stage 3 NREM)

Across the entire night, Stage N3 sleep usually accounts for about 15-25% of total sleep time in healthy adults.

rapid eye movement (REM) sleep

rapid eye movements, low muscle tone, and vivid dreams

occurs about 90mins after falling asleep.

brain activity is highly active

REM sleep is crucial for various functions like

memory consolidation, emotional regulation, and learning.

disruptions in REM sleep

can lead to diffioin concentration, memory problems, and emotional disturbances.

disturbances in REM sleep can lead to

sleep disorders like insomnia, sleep apnea, wnd REM sleep behavior disorder

disorders of sleep

insomnia disorder

hypersomnolence disorder

narcolepsy

obstructive sleep apnea hypoapnea

central sleep apnea

sleep related hypoventilation

insomnia disorder

dissatisfaction with sleep quantity or quality with complaints of difficulty initiating or maintaining sleep.

usually accompanied by clinically significant distress or impairment in social, occupational, or other important areas of functioning.

hypersomnolence disorder

symptoms of excessive quantity of sleep, sleepiness, and sleep inertia

sleep inertia

groggy, disoriented feeling that many people experience upon waking up from deep sleep or a nap. typically lasts for a few minute to half an hour after waking and can manifest as reduced cognitive functikn, impaired alertness, and difficulty performing tasks.

narcolepsy

involves excessive daytime sleepiness and sudden, uncontrollable episodes of falling asleep during the day

sleep paralysis

the phenomenon in which resumption of consciousness occurs while muscle atonia of REM sleep is maintained.

hypnagogic hallucinations

are imaginary images or sensations that seem real and occur as a person is falling asleep.

hypnopompic hallucinations

involve sensory experiences such as seeing or hearing things that aren't there. they occur during the transition from sleep to wakefulness, often as a person is ekerging from a dream state.

obstructive sleep apnea hypoapnea

repeated episodes of upper (pharyngeal) airway obstruction (apneas and hypoaneas) during sleep.

cardinal symptoms are snoring and daytime sleepiness.

central sleep apnea

repeated episodes of apneas and hypoapneas during sleep caused by fhe inability of the central nervous system to send.proper signals to muscles that control breathing

sleep related hypoventilation

a disorder characterized by inadequate ventilation during sleep, leading to elevated levels of carbon dioxie (hypercapnia) and sometimes decreased levels of oxygen (hypoxemia) in the blood.

more disorders of sleep

circadian rhythm sleep-wake disorders

Non-REM sleep arousal disorders

nightmare disorder

REM sleep movement sleep behavior disorder

restless legs syndrome

substance/medication-induced sleep disorder

why do we sleep

physical health

mental health

quality of life

longevity

physical health

cardiovascular health

metabolic health

immune function

cardiovascular health

studies have shown that insufficient sleep or poor sleep quality is associated with an increased risk of hypertension, heart disease, stroke, and other cardiovascular conditions

metabolic health

sleep plays a crucial role in regulating metabolism and insulin sensitivity. lack of sleep is linked to an increased risk of obesity, type 2 diabetes, and metabolic syndrome

immune function

adequate sleep is essential for proper immune function. research has shown that insufficient sleep can impair immune response, increasing susceptibility to infections and delaying recovery from illness.

mental health

mood disorders

cognitive function

emotional regulation

mood disorders

sleep distubances are strongly linked to mood disorders such as depression and anxiety. chronic sleep deprivation can exacerbate symptoms of these conditions and increase the risk of developing them.

cognitive function

sleep is critical for cognitive processes such as memory consolidation, learning, problem-solving, and decision-making. Studies have shown that sleep deprivation impairs cognitive function, attention, and reaction time.

emotional regulation

adequate sleep is important for emotional regulation and resilience. sleep deprivation can lead to heightened emotional reactivity, irritability, and decreased stress tolerance.n

quality of life

daytime functioning

quality of life

daytime functioning

good sleep is essential for optimal daytime functioning, including productivity, concentration, and ohysical performance.

quality of life

chronic sleep disturbances can significantly impact quality of life, leading to decreased energy levels, mood disturbances, and impaired social and occupational functioning.

longevity

Several epidemiological studies have suggested a link between sleep duration and mortality risk. Both short sleep duration (less than 7 hours per night) and long sleep duration (more than 9 hours per night) have been associated with an increased risk of mortality.

physiological mechanisms of sleep

chemical control of sleep

neural control of sleep

chemical control of sleep

melatonin

adenosine

orexin (hypocretin)

serotonin

GABA (gamma-aminobutryic acid)

dopamine and nonepinephrine

histamine

melatonin

produce by pineal gland, it is a hormone that plays a central role in regulating sleep-wake cycle. secretion is influenced by the body's internal circadiwn clock, with levels rising in the evening in response to darkness, promoting sleepiness, and declining during the day, promoting wakefulness.

adenosine

a neurotransmitter that accumulates in the brain during wakefulness and promotes sleep. it binds to adenosine receptors in the brain, inhibiting arousal-promoting neurotransmitters like dopamine and norepinephrine, thus promoting sleepiness. caffeine works by blocking the adenosine receptors, counteracting its sleep promoting effects

orexin (hypocretin)

produced by neurons in the hypothalamus. a neurotransmitter that promotes wakefulness and arousal. its deficiency is associated with narcolepsy, a sleep disorder characterized by excessive daytime eepiness and sudde loss of muscle tone (cataplexy)

serotonin

involved in regulating mood, appetite, and sleep wake cycles. it plays a role in promoting sleep by modulating REM sleep qnd promoting relaxation

gaba

a primary inhibitory neurotransmitter in the brain, and its activity promotes sleep by reducing neuronal excitability and promoting relaxation.

dopamine and norepinephrine

neurotransmitters involved in promoting wakefulness and arousal. their activity is suppressed during sleep, allowing for the transition into and maintenance of sleep

histamine

produced by neurons in the hypothalamus, promotes wakefulness and arousal by activating the receptors in the brain. antihistamine medications which block histamine receptors, can cause drowsiness and are sometimes used as sleep aids.

neural control of sleep

hypothalamus

brainstem

thalamus

basal forebrain

cortex

reticular formation

hypothalamus

plays a central role in the regulation of the sleep-wake cycle. it contains nuclei responsible for promoting wakefulness (orexin/hypocretin neurons in the lateral hypothalamus) and nuclei responsible for promoting sleep (ventrolateral peoptic nucleus, VLPO)

VLPO

ventrolateral preoptic nucleus

ventrolateral preoptic nucleus

it inhibits wake-promoting regions and promotes sleep onset

brainstem

several of this nuclei are involved in sleep regulation, including the reticular activating system (RAS) and the locus coeruleus (LC). RAS contains clusters of neurons that regulate arousal and wakefulness, while LC releases nonepinephrine to promote wakefulness. during sleep, these brainstem nuclei become less active

thalamus

it acts as a relay station for sensory information and plays a role in regulating arousal and consciousness. specific nuclei within the thalamus are involved in promoting wakefulness and transmitting sensory information to the cortex during wakefulness. during sleep, thalamic activity decreases, leading to sensory gating and reduced awareness of external environment.

basal forebrain

contains cholinergic neurons that promote wakefulness and arousal. these neurons project to the cortex and other brain regions, modulating cortical activity and promoting wakefulness. during sleep, activity in basal forebrain chrolinergic neurons decreases

cortex

involved in the generation and modulation of sleep patterns. different regions of the cortex exhibit distinct patterns of activity during wakefulness, NREM and REM sleep. cortical activity is coordinated by interactions with subcortical structures and thalamocortical circuits.

reticular formation

located in the brainstem, contains nuclei that regulate arousal and consciousness. it receives input from sensory systems and projects to the cortex and other brain regions to modulate arousal levels.

biological clocks also called as

circadian rhythm

biological clocks aka circadian rhythm

regulation of sleep is processed by the homeostatic physiology of the circadian rhythm, the sleep/wake cycle. our physiology and behavior are shaped by the Earth's rotation around its axis.

circadian rhythm

is a 24 hour internal clock in our brain that regulates cycles of alertness and sleepiness by responding to light changes in our environment