SLEEP

Questions and Answers

What is the primary function of the suprachiasmatic nucleus in relation to sleep?

Synchronizing biological rhythms to environmental light cues (correct)

Controlling REM sleep cycles

Facilitating dreaming processes

Regulating heart rate during sleep

Which of the following neurotransmitters is primarily associated with the functioning of the suprachiasmatic nucleus?

Dopamine

GABA (correct)

Serotonin

Norepinephrine

What is a defining characteristic of central sleep apnea?

Brain fails to signal respiratory muscles (correct)

Partial obstruction of the airway

Characterized by excessive daytime sleepiness

Physical acting out of dreams

Which external factor is considered the main zeitgeber for the suprachiasmatic nucleus?

Light exposure Signup and view all the answers

Which statement accurately describes obstructive sleep apnea?

It involves complete blockage of the upper airway. Signup and view all the answers

What effect does the ablation of the suprachiasmatic nucleus have on circadian rhythms in animals?

Circadian rhythms are lost Signup and view all the answers

What is a common behavior during somnambulism?

Purposeful movements while asleep Signup and view all the answers

What are biologic clocks primarily responsible for regulating?

Day-night cycle coordination in various biological processes Signup and view all the answers

What is a characteristic feature of narcolepsy?

Directly entering REM sleep from wakefulness Signup and view all the answers

What might disrupt the temporary atonia of REM sleep?

Underlying degenerative neurological conditions Signup and view all the answers

What is the primary role of GABA in sleep regulation?

Mediates sleep promoting activity through its interactions with the GABA-A receptor Signup and view all the answers

Which of the following factors can affect an individual's chronotype?

Mutations in the Period 1 and Period 2 genes Signup and view all the answers

In which sleep phase does somnambulism typically occur?

N3 deep sleep phase Signup and view all the answers

In narcolepsy, what does cataplexy refer to?

Temporary loss of muscle strength Signup and view all the answers

Which neurotransmitter is associated with promoting wakefulness?

Acetylcholine Signup and view all the answers

What is a key characteristic of sleep as a biological process?

It serves as an energy-conserving strategy Signup and view all the answers

What age group is most commonly associated with somnambulism?

School-aged children Signup and view all the answers

How does the function of sleep contribute to neural processes?

It facilitates targeted erasure of synapses for memory clarity Signup and view all the answers

What is likely to happen to sleep patterns as individuals age?

Reduced quality and quantity of sleep Signup and view all the answers

Which factor can potentially influence gender differences in sleep patterns?

Hormonal changes during the menstrual cycle Signup and view all the answers

Which of the following behaviors is commonly associated with sleep?

Resting and snoring Signup and view all the answers

What typically happens during the daily cycle of circadian rhythms?

Gene turn-on followed by gene turn-off in a loop Signup and view all the answers

Which neurotransmitter inhibits wakefulness promoting neurons?

Adenosine Signup and view all the answers

Which stage of sleep is characterized by the lowest frequency and highest amplitude EEG activity?

N3 Stage Signup and view all the answers

What percentage of total sleep time is typically spent in REM sleep?

25% Signup and view all the answers

During which stage of sleep might muscle tone be absent and rapid eye movement occur?

REM Stage Signup and view all the answers

What common sleep phenomenon may occur during N3 sleep?

Sleepwalking Signup and view all the answers

What is the approximate duration of a complete sleep cycle?

90 to 110 minutes Signup and view all the answers

In what sleep stage does bruxism most commonly occur?

N2 Stage Signup and view all the answers

How does sleep behavior in newborns typically manifest in the first few weeks of life?

Distributed sleep across day and night Signup and view all the answers

What is one major change in sleep patterns as people age?

Decreased deep sleep (N3) and increased N2 sleep Signup and view all the answers

What is typically observed in the EEG activity during wakefulness when a person is relaxed with closed eyes?

Alpha rhythm Signup and view all the answers

What physiological characteristic is often associated with REM sleep?

Highly active brain metabolism Signup and view all the answers

What pattern is typical for men's sleep as they age?

More nighttime awakenings Signup and view all the answers

What role does the reticular activating system (RAS) play in sleep?

It produces desynchronized EEG associated with waking Signup and view all the answers

Which area of the brain is responsible for REM sleep?

Peribrachial area Signup and view all the answers

How does sleep apnea affect sleep stages?

Decreases REM sleep time Signup and view all the answers

Which gender is more likely to maintain slow-wave sleep as they age?

Women Signup and view all the answers

What neurotransmitter is associated with the waking EEG produced by the basal forebrain?

Acetylcholine Signup and view all the answers

What happens to individuals with damage to the area responsible for REM sleep?

They may reduce or abolish REM sleep Signup and view all the answers

What is the effect of pregnancy on daytime sleepiness?

It increases during pregnancy Signup and view all the answers

Which of the following cells are primarily involved in stimulating the waking EEG from the basal forebrain?

Cholinergic cells Signup and view all the answers

Which brain region is associated with movement and contributes to a waking EEG?

Median raphe Signup and view all the answers

What is the primary function of the Period 1 and Period 2 genes in relation to biorhythms?

They determine chronotype, affecting sleep patterns. Signup and view all the answers

Which neurotransmitter is primarily involved in promoting wakefulness?

Dopamine Signup and view all the answers

What characterizes non-rapid eye movement (NREM) sleep stages?

Decreased heart rate and blood pressure. Signup and view all the answers

What is the role of GABA in the cellular basis of sleep?

Facilitates sleep by interacting with receptors. Signup and view all the answers

Which of the following best describes the function of sleep in relation to neural activity?

Sleep actively erases unnecessary synapses to help memory. Signup and view all the answers

How does adenosine affect wakefulness-promoting neurons?

It inhibits their function. Signup and view all the answers

What is the primary biological adaptation function of sleep?

To conserve energy during food scarcity. Signup and view all the answers

Which of the following describes the concept of a biorhythm?

An inherent biological cycle affecting physiological processes. Signup and view all the answers

What is the primary problem associated with obstructive sleep apnea?

There is a partial or complete blockage of the upper airway Signup and view all the answers

Which disorder is characterized by persistent daytime sleepiness and episodes of muscle weakness?

Narcolepsy Signup and view all the answers

What is the typical behavior exhibited by individuals during somnambulism?

Performing purposeful movements Signup and view all the answers

Which of the following conditions may be associated with REM sleep disorder?

Parkinson disease Signup and view all the answers

During what phase of sleep do individuals with narcolepsy tend to enter immediately?

REM sleep Signup and view all the answers

What causes the temporary atonia of REM sleep to be disturbed?

Neurodegenerative disorders Signup and view all the answers

What are biological rhythms primarily defined as?

Inherent timing mechanisms regulating biological processes Signup and view all the answers

What phase of sleep is somnambulism most commonly associated with?

N3 sleep Signup and view all the answers

What characterizes central sleep apnea?

The brain fails to signal respiratory muscles Signup and view all the answers

What is the primary role of the suprachiasmatic nucleus?

Acting as the main biological clock Signup and view all the answers

What do zeitgebers refer to in the context of sleep regulation?

Time-givers that help entrain biological rhythms Signup and view all the answers

What typical sleep problem occurs when the sleep cycle is still maturing in children?

Somnambulism Signup and view all the answers

What best describes cataplexy in narcolepsy?

Sudden brief loss of muscle strength Signup and view all the answers

What is a key component of the biological clock that allows organisms to anticipate events?

Cognitive and physiological preparation Signup and view all the answers

What does the core region of the suprachiasmatic nucleus primarily do?

Entrains the shell neurons Signup and view all the answers

What characterizes the N1 stage of sleep?

It is associated with theta rhythm and consists of light sleep. Signup and view all the answers

What physiological changes occur during the N3 stage of sleep?

Difficult to awaken, associated with deep sleep and delta rhythm. Signup and view all the answers

What is the primary characteristic of REM sleep?

Absence of muscle tone and occurrence of dreams. Signup and view all the answers

Which EEG pattern is associated with being awake and relaxed with closed eyes?

Alpha rhythm. Signup and view all the answers

What happens to REM sleep duration as the night progresses?

It becomes longer with each successive sleep cycle. Signup and view all the answers

What describes the changes in heart rate and body temperature during the N2 stage of sleep?

Both heart rate and body temperature decrease. Signup and view all the answers

What is an important characteristic of the sleep cycle?

It cycles between NREM and REM stages approximately 4 to 6 times a night. Signup and view all the answers

What occurs during the N3 stage of sleep?

Sleepwalking, night terrors, and bedwetting can occur. Signup and view all the answers

How much of total sleep time is typically spent in NREM sleep by adults?

75%. Signup and view all the answers

What type of rhythm is observed during the REM stage of sleep?

Beta rhythm. Signup and view all the answers

What is the role of the reticular activating system (RAS) in sleep regulation?

It is responsible for waking EEG patterns. Signup and view all the answers

What is the primary function of the basal forebrain in relation to sleep?

To promote a waking EEG via acetylcholine secretion. Signup and view all the answers

In which area of the brain is REM sleep primarily regulated?

Peribrachial area Signup and view all the answers

What commonly occurs to individuals with sleep apnea during sleep?

Frequent awakenings due to airway collapse. Signup and view all the answers

What neurotransmitter is predominantly involved in waking EEG activity related to movement?

Serotonin Signup and view all the answers

What effect does damage to the reticular activating system (RAS) have on EEG patterns?

It produces a slow-wave, sleep-like EEG. Signup and view all the answers

What characterizes the stage of sleep known as N1 sleep?

A transition phase from wakefulness to sleep. Signup and view all the answers

What is one result of increased daytime sleepiness during pregnancy?

Difficulty falling asleep at night. Signup and view all the answers

What does the term 'cholinergic' refer to in the context of sleep?

Associated with acetylcholine activity. Signup and view all the answers

What happens to sleep patterns as individuals age?

They experience reduced sleep efficiency. Signup and view all the answers

Study Notes

Molecular Basis of the Biological Clock

CB dimer activity leads to the expression of Per and Cry genes, restarting the 24-hour cycle.
Circadian rhythm is a result of gene turn-on and turn-off cycles, with mutations affecting rhythms.
Alleles of Period 1 and Period 2 genes influence an individual's chronotype, determining sleep patterns.

Physiology of Sleep

Sleep serves as a biological adaptation, conserving energy during food scarcity and enhancing alertness.
Facilitates neural maturation, learning, memory retention, and clearance of metabolic waste products.
Activities during sleep include resting, napping, and sleep-related events like snoring and dreaming.

Cellular Basis of Sleep

Sleep promotion involves GABA interactions with GABA-A receptors and adenosine inhibiting wakefulness-promoting neurons.
Key wakefulness-promoting neurotransmitters include acetylcholine, dopamine, norepinephrine, serotonin, histamine, and hypocretin.

Stages of Sleep

Sleep consists of multiple stages: waking, non-REM (N1, N2, N3), and REM sleep.
A complete sleep cycle lasts 90 to 110 minutes and typically occurs 4 to 6 times per night.

Sleep Apnea

Two types: central sleep apnea results from the brain failing to signal respiratory muscles; obstructive sleep apnea involves airway blockage during sleep.
Sleep apnea leads to excessive daytime drowsiness due to reduced time in deep sleep stages.

REM Sleep Disorder

Disruption of REM atonia can result in physically acting out dreams with vocalizations and movements.
Often associated with neurological conditions like Parkinson's disease.

Narcolepsy

Characterized by excessive daytime sleepiness and cataplexy, where individuals enter REM sleep directly.
Involves sudden loss of muscle strength and irregular sleep patterns, limiting restorative deep sleep.

Somnambulism

Sleepwalking, common in children, involves purposeful movements during N3 non-REM sleep.
Occurs due to maturing sleep cycles, resulting in unregulated sleep/wake transitions.

Evolution of Sleep through Aging

Aging affects sleep patterns: children experience irregular sleep, while older adults tend to experience less deep sleep.
Men typically spend more time in N1, while women maintain slow-wave sleep longer.

Neural Basis of Sleep

Reticular activating system (RAS) plays a crucial role in sleep regulation; stimulation produces desynchronized EEG patterns associated with waking.
Key regions include the basal forebrain, which secretes acetylcholine to enhance alertness, and the median raphe responsible for serotonin release.

Neural Basis of REM Sleep

The peribrachial area is essential for REM sleep regulation; damage here can abolish REM stages.
Activation during REM leads to muscle atonia, increased brain metabolism, and irregular breathing.

Stages of Sleep Overview

N1: Lightest sleep; lasts 1-5 minutes; EEG shows theta rhythm.
N2: Deeper sleep; makes up 45% of sleep; characterized by sleep spindles and K complexes.
N3: Deep sleep, essential for physical recovery; EEG shows delta rhythms; sleepwalking can occur.
REM: 25% of sleep; involved in dreaming; marked by high brain activity and muscle atonia.

Biological Rhythms and the Suprachiasmatic Nucleus

Biological rhythms regulate various processes linked to Earth's cycles, influencing feeding, sleeping, and metabolic activity.
The suprachiasmatic nucleus (SCN) is the main biological clock, responsible for generating circadian rhythms.
SCN neurons utilize GABA as their main neurotransmitter, ensuring synchronized rhythmic activity.
Zeitgebers, primarily light, help entrain SCN neurons to align with solar days, also influenced by factors like feeding and mobility.
Increased SCN activity during light periods is demonstrated by tracer studies in rodents.