Sleep Physiology Flashcards
What are the two main types of sleep?
The two main types of sleep are Non-Rapid Eye Movement (NREM) sleep and Rapid Eye Movement (REM) sleep. NREM sleep is divided into three stages, while REM sleep is associated with dreaming.
What happens during Stage 1 of NREM sleep?
Stage 1 is the lightest sleep stage, lasting 1-7 minutes. It’s the transition from wakefulness to sleep. Brain waves slow, muscle activity decreases, and the sleeper can be easily awakened.
What is the key characteristic of Stage 2 sleep?
Stage 2 is characterized by the appearance of sleep spindles and K-complexes. Sleep spindles are bursts of rapid brain activity, while K-complexes are sudden, high-amplitude waves. This stage is associated with memory consolidation.
What happens during REM sleep?
REM sleep is marked by rapid eye movements, vivid dreams, and heightened brain activity similar to wakefulness. It is crucial for emotional regulation and memory consolidation, particularly of procedural memory.
What are slow-wave sleep (SWS) and its role?
Slow-wave sleep (SWS) occurs during Stage 3 of NREM sleep. It is characterized by delta waves, the slowest brainwaves. SWS is essential for physical restoration, immune function, and memory consolidation.
How does the sleep cycle progress throughout the night?
The sleep cycle repeats approximately every 90 minutes, alternating between NREM and REM sleep. Early in the night, NREM stages dominate, with more REM sleep occurring in the second half of the night.
What is the role of the circadian rhythm in sleep?
The circadian rhythm is the body’s internal clock, which regulates sleep-wake cycles over a 24-hour period. It is influenced by light and controls the release of hormones like melatonin that promote sleep.
Which neurotransmitter is crucial for initiating sleep?
GABA (gamma-aminobutyric acid) is the primary inhibitory neurotransmitter that promotes sleep by reducing neuronal activity and inducing relaxation.
What hormone is primarily responsible for regulating sleep-wake cycles?
Melatonin, produced by the pineal gland in response to darkness, is responsible for regulating sleep-wake cycles. Its levels rise in the evening and fall in the morning.
What is sleep pressure, and how is it regulated?
Sleep pressure is the body’s drive to sleep, which increases the longer a person is awake. It is regulated by adenosine, a chemical that builds up in the brain during wakefulness and promotes sleep.
What brain region is essential for regulating sleep and wakefulness?
The hypothalamus, particularly the suprachiasmatic nucleus (SCN), regulates sleep and wakefulness by controlling circadian rhythms and hormone release.
What is the function of the reticular activating system (RAS) in sleep?
The reticular activating system (RAS) is involved in maintaining wakefulness and alertness. It is inhibited during sleep, particularly during NREM sleep, to reduce arousal.
What is sleep homeostasis?
Sleep homeostasis is the balance between sleep and wakefulness, governed by sleep need. The longer you’re awake, the stronger your need for sleep becomes, promoting recovery during rest.
What changes in brain wave activity occur during sleep?
During wakefulness, beta waves dominate. In Stage 1 sleep, alpha and theta waves emerge. In Stage 2, theta waves continue with sleep spindles. Slow-wave sleep features delta waves, and REM sleep resembles wakefulness with fast, low-amplitude beta waves.
How does REM sleep contribute to memory?
REM sleep is critical for consolidating procedural and emotional memories. It helps process and store experiences, supporting learning and emotional regulation.
